CINXE.COM

<!DOCTYPE html> <html class="client-nojs vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available" lang="en" dir="ltr"> <head> <meta charset="UTF-8"> <title>History of atomic theory - Wikipedia</title> <script>(function(){var className="client-js vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available";var cookie=document.cookie.match(/(?:^|; )enwikimwclientpreferences=([^;]+)/);if(cookie){cookie[1].split('%2C').forEach(function(pref){className=className.replace(new RegExp('(^| )'+pref.replace(/-clientpref-\w+$|[^\w-]+/g,'')+'-clientpref-\\w+( |$)'),'$1'+pref+'$2');});}document.documentElement.className=className;}());RLCONF={"wgBreakFrames":false,"wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"dmy", "wgMonthNames":["","January","February","March","April","May","June","July","August","September","October","November","December"],"wgRequestId":"c1832679-34ed-40a3-b2e2-6114ecf23381","wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"History_of_atomic_theory","wgTitle":"History of atomic theory","wgCurRevisionId":1257505012,"wgRevisionId":1257505012,"wgArticleId":2844,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["Articles with short description","Short description is different from Wikidata","Wikipedia pages semi-protected against vandalism","Good articles","All articles with unsourced statements","Articles with unsourced statements from October 2024","Pages using multiple image with auto scaled images","Articles needing cleanup from November 2024","All pages needing cleanup","Articles with sections that need to be turned into prose from November 2024","Atomic physics", "Amount of substance","Chemistry theories","Foundational quantum physics","Statistical mechanics"],"wgPageViewLanguage":"en","wgPageContentLanguage":"en","wgPageContentModel":"wikitext","wgRelevantPageName":"History_of_atomic_theory","wgRelevantArticleId":2844,"wgIsProbablyEditable":false,"wgRelevantPageIsProbablyEditable":false,"wgRestrictionEdit":["autoconfirmed"],"wgRestrictionMove":[],"wgRedirectedFrom":"Atomic_theory","wgNoticeProject":"wikipedia","wgCiteReferencePreviewsActive":false,"wgFlaggedRevsParams":{"tags":{"status":{"levels":1}}},"wgMediaViewerOnClick":true,"wgMediaViewerEnabledByDefault":true,"wgPopupsFlags":0,"wgVisualEditor":{"pageLanguageCode":"en","pageLanguageDir":"ltr","pageVariantFallbacks":"en"},"wgMFDisplayWikibaseDescriptions":{"search":true,"watchlist":true,"tagline":false,"nearby":true},"wgWMESchemaEditAttemptStepOversample":false,"wgWMEPageLength":80000,"wgInternalRedirectTargetUrl":"/wiki/History_of_atomic_theory","wgRelatedArticlesCompat":[], "wgCentralAuthMobileDomain":false,"wgEditSubmitButtonLabelPublish":true,"wgULSPosition":"interlanguage","wgULSisCompactLinksEnabled":false,"wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q210553","wgCheckUserClientHintsHeadersJsApi":["brands","architecture","bitness","fullVersionList","mobile","model","platform","platformVersion"],"GEHomepageSuggestedEditsEnableTopics":true,"wgGETopicsMatchModeEnabled":false,"wgGEStructuredTaskRejectionReasonTextInputEnabled":false,"wgGELevelingUpEnabledForUser":false};RLSTATE={"ext.globalCssJs.user.styles":"ready","site.styles":"ready","user.styles":"ready","ext.globalCssJs.user":"ready","user":"ready","user.options":"loading","ext.cite.styles":"ready","skins.vector.search.codex.styles":"ready","skins.vector.styles":"ready","skins.vector.icons":"ready","jquery.makeCollapsible.styles":"ready","ext.wikimediamessages.styles":"ready","ext.visualEditor.desktopArticleTarget.noscript":"ready", "ext.uls.interlanguage":"ready","wikibase.client.init":"ready","ext.wikimediaBadges":"ready"};RLPAGEMODULES=["mediawiki.action.view.redirect","ext.cite.ux-enhancements","mediawiki.page.media","ext.scribunto.logs","site","mediawiki.page.ready","jquery.makeCollapsible","mediawiki.toc","skins.vector.js","ext.centralNotice.geoIP","ext.centralNotice.startUp","ext.gadget.ReferenceTooltips","ext.gadget.switcher","ext.urlShortener.toolbar","ext.centralauth.centralautologin","mmv.bootstrap","ext.popups","ext.visualEditor.desktopArticleTarget.init","ext.visualEditor.targetLoader","ext.echo.centralauth","ext.eventLogging","ext.wikimediaEvents","ext.navigationTiming","ext.uls.interface","ext.cx.eventlogging.campaigns","ext.cx.uls.quick.actions","wikibase.client.vector-2022","ext.checkUser.clientHints","ext.growthExperiments.SuggestedEditSession","wikibase.sidebar.tracking"];</script> <script>(RLQ=window.RLQ||[]).push(function(){mw.loader.impl(function(){return["user.options@12s5i",function($,jQuery,require,module){mw.user.tokens.set({"patrolToken":"+\\","watchToken":"+\\","csrfToken":"+\\"}); }];});});</script> <link rel="stylesheet" href="/w/load.php?lang=en&modules=ext.cite.styles%7Cext.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediaBadges%7Cext.wikimediamessages.styles%7Cjquery.makeCollapsible.styles%7Cskins.vector.icons%2Cstyles%7Cskins.vector.search.codex.styles%7Cwikibase.client.init&only=styles&skin=vector-2022"> <script async="" src="/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=vector-2022"></script> <meta name="ResourceLoaderDynamicStyles" content=""> <link rel="stylesheet" href="/w/load.php?lang=en&modules=site.styles&only=styles&skin=vector-2022"> <meta name="generator" content="MediaWiki 1.44.0-wmf.4"> <meta name="referrer" content="origin"> <meta name="referrer" content="origin-when-cross-origin"> <meta name="robots" content="max-image-preview:standard"> <meta name="format-detection" content="telephone=no"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/thumb/2/23/Helium_atom_QM.svg/1200px-Helium_atom_QM.svg.png"> <meta property="og:image:width" content="1200"> <meta property="og:image:height" content="1204"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/thumb/2/23/Helium_atom_QM.svg/800px-Helium_atom_QM.svg.png"> <meta property="og:image:width" content="800"> <meta property="og:image:height" content="802"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/thumb/2/23/Helium_atom_QM.svg/640px-Helium_atom_QM.svg.png"> <meta property="og:image:width" content="640"> <meta property="og:image:height" content="642"> <meta name="viewport" content="width=1120"> <meta property="og:title" content="History of atomic theory - Wikipedia"> <meta property="og:type" content="website"> <link rel="preconnect" href="//upload.wikimedia.org"> <link rel="alternate" media="only screen and (max-width: 640px)" href="//en.m.wikipedia.org/wiki/History_of_atomic_theory"> <link rel="apple-touch-icon" href="/static/apple-touch/wikipedia.png"> <link rel="icon" href="/static/favicon/wikipedia.ico"> <link rel="search" type="application/opensearchdescription+xml" href="/w/rest.php/v1/search" title="Wikipedia (en)"> <link rel="EditURI" type="application/rsd+xml" href="//en.wikipedia.org/w/api.php?action=rsd"> <link rel="canonical" href="https://en.wikipedia.org/wiki/History_of_atomic_theory"> <link rel="license" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en"> <link rel="alternate" type="application/atom+xml" title="Wikipedia Atom feed" href="/w/index.php?title=Special:RecentChanges&feed=atom"> <link rel="dns-prefetch" href="//meta.wikimedia.org" /> <link rel="dns-prefetch" href="//login.wikimedia.org"> </head> <body class="skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-History_of_atomic_theory rootpage-History_of_atomic_theory skin-vector-2022 action-view"><a class="mw-jump-link" href="#bodyContent">Jump to content</a> <div class="vector-header-container"> <header class="vector-header mw-header"> <div class="vector-header-start"> <nav class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-dropdown" class="vector-dropdown vector-main-menu-dropdown vector-button-flush-left vector-button-flush-right" > <input type="checkbox" id="vector-main-menu-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-main-menu-dropdown" class="vector-dropdown-checkbox " aria-label="Main menu" > <label id="vector-main-menu-dropdown-label" for="vector-main-menu-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-menu mw-ui-icon-wikimedia-menu"></span> <span class="vector-dropdown-label-text">Main menu</span> </label> <div class="vector-dropdown-content"> <div id="vector-main-menu-unpinned-container" class="vector-unpinned-container"> <div id="vector-main-menu" class="vector-main-menu vector-pinnable-element"> <div class="vector-pinnable-header vector-main-menu-pinnable-header vector-pinnable-header-unpinned" data-feature-name="main-menu-pinned" data-pinnable-element-id="vector-main-menu" data-pinned-container-id="vector-main-menu-pinned-container" data-unpinned-container-id="vector-main-menu-unpinned-container" > <div class="vector-pinnable-header-label">Main menu</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-main-menu.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-main-menu.unpin">hide</button> </div> <div id="p-navigation" class="vector-menu mw-portlet mw-portlet-navigation" > <div class="vector-menu-heading"> Navigation </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-mainpage-description" class="mw-list-item"><a href="/wiki/Main_Page" title="Visit the main page [z]" accesskey="z"><span>Main page</span></a></li><li id="n-contents" class="mw-list-item"><a href="/wiki/Wikipedia:Contents" title="Guides to browsing Wikipedia"><span>Contents</span></a></li><li id="n-currentevents" class="mw-list-item"><a href="/wiki/Portal:Current_events" title="Articles related to current events"><span>Current events</span></a></li><li id="n-randompage" class="mw-list-item"><a href="/wiki/Special:Random" title="Visit a randomly selected article [x]" accesskey="x"><span>Random article</span></a></li><li id="n-aboutsite" class="mw-list-item"><a href="/wiki/Wikipedia:About" title="Learn about Wikipedia and how it works"><span>About Wikipedia</span></a></li><li id="n-contactpage" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us" title="How to contact Wikipedia"><span>Contact us</span></a></li> </ul> </div> </div> <div id="p-interaction" class="vector-menu mw-portlet mw-portlet-interaction" > <div class="vector-menu-heading"> Contribute </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-help" class="mw-list-item"><a href="/wiki/Help:Contents" title="Guidance on how to use and edit Wikipedia"><span>Help</span></a></li><li id="n-introduction" class="mw-list-item"><a href="/wiki/Help:Introduction" title="Learn how to edit Wikipedia"><span>Learn to edit</span></a></li><li id="n-portal" class="mw-list-item"><a href="/wiki/Wikipedia:Community_portal" title="The hub for editors"><span>Community portal</span></a></li><li id="n-recentchanges" class="mw-list-item"><a href="/wiki/Special:RecentChanges" title="A list of recent changes to Wikipedia [r]" accesskey="r"><span>Recent changes</span></a></li><li id="n-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_upload_wizard" title="Add images or other media for use on Wikipedia"><span>Upload file</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> <a href="/wiki/Main_Page" class="mw-logo"> <img class="mw-logo-icon" src="/static/images/icons/wikipedia.png" alt="" aria-hidden="true" height="50" width="50"> <span class="mw-logo-container skin-invert"> <img class="mw-logo-wordmark" alt="Wikipedia" src="/static/images/mobile/copyright/wikipedia-wordmark-en.svg" style="width: 7.5em; height: 1.125em;"> <img class="mw-logo-tagline" alt="The Free Encyclopedia" src="/static/images/mobile/copyright/wikipedia-tagline-en.svg" width="117" height="13" style="width: 7.3125em; height: 0.8125em;"> </span> </a> </div> <div class="vector-header-end"> <div id="p-search" role="search" class="vector-search-box-vue vector-search-box-collapses vector-search-box-show-thumbnail vector-search-box-auto-expand-width vector-search-box"> <a href="/wiki/Special:Search" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only search-toggle" title="Search Wikipedia [f]" accesskey="f"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>Search</span> </a> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail cdx-typeahead-search--auto-expand-width"> <form action="/w/index.php" id="searchform" class="cdx-search-input cdx-search-input--has-end-button"> <div id="simpleSearch" class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia" aria-label="Search Wikipedia" autocapitalize="sentences" title="Search Wikipedia [f]" accesskey="f" id="searchInput" > <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <nav class="vector-user-links vector-user-links-wide" aria-label="Personal tools"> <div class="vector-user-links-main"> <div id="p-vector-user-menu-preferences" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-userpage" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-dropdown" class="vector-dropdown " title="Change the appearance of the page's font size, width, and color" > <input type="checkbox" id="vector-appearance-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-appearance-dropdown" class="vector-dropdown-checkbox " aria-label="Appearance" > <label id="vector-appearance-dropdown-label" for="vector-appearance-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-appearance mw-ui-icon-wikimedia-appearance"></span> <span class="vector-dropdown-label-text">Appearance</span> </label> <div class="vector-dropdown-content"> <div id="vector-appearance-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div id="p-vector-user-menu-notifications" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-overflow" class="vector-menu mw-portlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en" class=""><span>Donate</span></a> </li> <li id="pt-createaccount-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:CreateAccount&returnto=History+of+atomic+theory" title="You are encouraged to create an account and log in; however, it is not mandatory" class=""><span>Create account</span></a> </li> <li id="pt-login-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:UserLogin&returnto=History+of+atomic+theory" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o" class=""><span>Log in</span></a> </li> </ul> </div> </div> </div> <div id="vector-user-links-dropdown" class="vector-dropdown vector-user-menu vector-button-flush-right vector-user-menu-logged-out" title="Log in and more options" > <input type="checkbox" id="vector-user-links-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-user-links-dropdown" class="vector-dropdown-checkbox " aria-label="Personal tools" > <label id="vector-user-links-dropdown-label" for="vector-user-links-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-ellipsis mw-ui-icon-wikimedia-ellipsis"></span> <span class="vector-dropdown-label-text">Personal tools</span> </label> <div class="vector-dropdown-content"> <div id="p-personal" class="vector-menu mw-portlet mw-portlet-personal user-links-collapsible-item" title="User menu" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport" class="user-links-collapsible-item mw-list-item"><a href="https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en"><span>Donate</span></a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:CreateAccount&returnto=History+of+atomic+theory" title="You are encouraged to create an account and log in; however, it is not mandatory"><span class="vector-icon mw-ui-icon-userAdd mw-ui-icon-wikimedia-userAdd"></span> <span>Create account</span></a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:UserLogin&returnto=History+of+atomic+theory" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o"><span class="vector-icon mw-ui-icon-logIn mw-ui-icon-wikimedia-logIn"></span> <span>Log in</span></a></li> </ul> </div> </div> <div id="p-user-menu-anon-editor" class="vector-menu mw-portlet mw-portlet-user-menu-anon-editor" > <div class="vector-menu-heading"> Pages for logged out editors <a href="/wiki/Help:Introduction" aria-label="Learn more about editing"><span>learn more</span></a> </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-anoncontribs" class="mw-list-item"><a href="/wiki/Special:MyContributions" title="A list of edits made from this IP address [y]" accesskey="y"><span>Contributions</span></a></li><li id="pt-anontalk" class="mw-list-item"><a href="/wiki/Special:MyTalk" title="Discussion about edits from this IP address [n]" accesskey="n"><span>Talk</span></a></li> </ul> </div> </div> </div> </div> </nav> </div> </header> </div> <div class="mw-page-container"> <div class="mw-page-container-inner"> <div class="vector-sitenotice-container"> <div id="siteNotice"></div> </div> <div class="vector-column-start"> <div class="vector-main-menu-container"> <div id="mw-navigation"> <nav id="mw-panel" class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-pinned-container" class="vector-pinned-container"> </div> </nav> </div> </div> <div class="vector-sticky-pinned-container"> <nav id="mw-panel-toc" aria-label="Contents" data-event-name="ui.sidebar-toc" class="mw-table-of-contents-container vector-toc-landmark"> <div id="vector-toc-pinned-container" class="vector-pinned-container"> <div id="vector-toc" class="vector-toc vector-pinnable-element"> <div class="vector-pinnable-header vector-toc-pinnable-header vector-pinnable-header-pinned" data-feature-name="toc-pinned" data-pinnable-element-id="vector-toc" > <h2 class="vector-pinnable-header-label">Contents</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">hide</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">(Top)</div> </a> </li> <li id="toc-Philosophical_atomism" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Philosophical_atomism"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>Philosophical atomism</span> </div> </a> <ul id="toc-Philosophical_atomism-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Groundwork" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Groundwork"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Groundwork</span> </div> </a> <ul id="toc-Groundwork-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Dalton's_law_of_multiple_proportions" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Dalton's_law_of_multiple_proportions"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Dalton's law of multiple proportions</span> </div> </a> <ul id="toc-Dalton's_law_of_multiple_proportions-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Opposition_to_atomic_theory" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Opposition_to_atomic_theory"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Opposition to atomic theory</span> </div> </a> <ul id="toc-Opposition_to_atomic_theory-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Isomerism" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Isomerism"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Isomerism</span> </div> </a> <ul id="toc-Isomerism-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Mendeleev's_periodic_table" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Mendeleev's_periodic_table"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Mendeleev's periodic table</span> </div> </a> <ul id="toc-Mendeleev's_periodic_table-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Statistical_mechanics" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Statistical_mechanics"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Statistical mechanics</span> </div> </a> <button aria-controls="toc-Statistical_mechanics-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Statistical mechanics subsection</span> </button> <ul id="toc-Statistical_mechanics-sublist" class="vector-toc-list"> <li id="toc-Brownian_motion" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Brownian_motion"> <div class="vector-toc-text"> <span class="vector-toc-numb">7.1</span> <span>Brownian motion</span> </div> </a> <ul id="toc-Brownian_motion-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Discovery_of_the_electron" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Discovery_of_the_electron"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>Discovery of the electron</span> </div> </a> <ul id="toc-Discovery_of_the_electron-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Discovery_of_the_nucleus" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Discovery_of_the_nucleus"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</span> <span>Discovery of the nucleus</span> </div> </a> <ul id="toc-Discovery_of_the_nucleus-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Bohr_model" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Bohr_model"> <div class="vector-toc-text"> <span class="vector-toc-numb">10</span> <span>Bohr model</span> </div> </a> <ul id="toc-Bohr_model-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Discovery_of_isotopes" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Discovery_of_isotopes"> <div class="vector-toc-text"> <span class="vector-toc-numb">11</span> <span>Discovery of isotopes</span> </div> </a> <ul id="toc-Discovery_of_isotopes-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Discovery_of_the_proton" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Discovery_of_the_proton"> <div class="vector-toc-text"> <span class="vector-toc-numb">12</span> <span>Discovery of the proton</span> </div> </a> <ul id="toc-Discovery_of_the_proton-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Discovery_of_the_neutron" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Discovery_of_the_neutron"> <div class="vector-toc-text"> <span class="vector-toc-numb">13</span> <span>Discovery of the neutron</span> </div> </a> <ul id="toc-Discovery_of_the_neutron-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Modern_quantum_mechanical_models" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Modern_quantum_mechanical_models"> <div class="vector-toc-text"> <span class="vector-toc-numb">14</span> <span>Modern quantum mechanical models</span> </div> </a> <ul id="toc-Modern_quantum_mechanical_models-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">15</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Footnotes" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Footnotes"> <div class="vector-toc-text"> <span class="vector-toc-numb">16</span> <span>Footnotes</span> </div> </a> <ul id="toc-Footnotes-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Bibliography" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Bibliography"> <div class="vector-toc-text"> <span class="vector-toc-numb">17</span> <span>Bibliography</span> </div> </a> <ul id="toc-Bibliography-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Further_reading" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Further_reading"> <div class="vector-toc-text"> <span class="vector-toc-numb">18</span> <span>Further reading</span> </div> </a> <ul id="toc-Further_reading-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">19</span> <span>External links</span> </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">History of atomic theory</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 60 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-60" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">60 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-anp mw-list-item"><a href="https://anp.wikipedia.org/wiki/%E0%A4%AA%E0%A4%B0%E0%A4%AE%E0%A4%BE%E0%A4%A3%E0%A5%81_%E0%A4%B8%E0%A4%BF%E0%A4%A6%E0%A5%8D%E0%A4%A7%E0%A4%BE%E0%A4%82%E0%A4%A4" title="परमाणु सिद्धांत – Angika" lang="anp" hreflang="anp" data-title="परमाणु सिद्धांत" data-language-autonym="अंगिका" data-language-local-name="Angika" class="interlanguage-link-target"><span>अंगिका</span></a></li><li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D9%86%D8%B8%D8%B1%D9%8A%D8%A9_%D8%B0%D8%B1%D9%8A%D8%A9" title="نظرية ذرية – Arabic" lang="ar" hreflang="ar" data-title="نظرية ذرية" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-ast mw-list-item"><a href="https://ast.wikipedia.org/wiki/Teor%C3%ADa_at%C3%B3mica" title="Teoría atómica – Asturian" lang="ast" hreflang="ast" data-title="Teoría atómica" data-language-autonym="Asturianu" data-language-local-name="Asturian" class="interlanguage-link-target"><span>Asturianu</span></a></li><li class="interlanguage-link interwiki-bn mw-list-item"><a href="https://bn.wikipedia.org/wiki/%E0%A6%AA%E0%A6%BE%E0%A6%B0%E0%A6%AE%E0%A6%BE%E0%A6%A3%E0%A6%AC%E0%A6%BF%E0%A6%95_%E0%A6%A4%E0%A6%A4%E0%A7%8D%E0%A6%A4%E0%A7%8D%E0%A6%AC" title="পারমাণবিক তত্ত্ব – Bangla" lang="bn" hreflang="bn" data-title="পারমাণবিক তত্ত্ব" data-language-autonym="বাংলা" data-language-local-name="Bangla" class="interlanguage-link-target"><span>বাংলা</span></a></li><li class="interlanguage-link interwiki-be mw-list-item"><a href="https://be.wikipedia.org/wiki/%D0%90%D1%82%D0%B0%D0%BC%D0%BD%D0%B0%D1%8F_%D1%82%D1%8D%D0%BE%D1%80%D1%8B%D1%8F" title="Атамная тэорыя – Belarusian" lang="be" hreflang="be" data-title="Атамная тэорыя" data-language-autonym="Беларуская" data-language-local-name="Belarusian" class="interlanguage-link-target"><span>Беларуская</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%90%D1%82%D0%BE%D0%BC%D0%BD%D0%B0_%D1%82%D0%B5%D0%BE%D1%80%D0%B8%D1%8F" title="Атомна теория – Bulgarian" lang="bg" hreflang="bg" data-title="Атомна теория" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-bs mw-list-item"><a href="https://bs.wikipedia.org/wiki/Atomska_teorija" title="Atomska teorija – Bosnian" lang="bs" hreflang="bs" data-title="Atomska teorija" data-language-autonym="Bosanski" data-language-local-name="Bosnian" class="interlanguage-link-target"><span>Bosanski</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Teoria_at%C3%B2mica" title="Teoria atòmica – Catalan" lang="ca" hreflang="ca" data-title="Teoria atòmica" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cv mw-list-item"><a href="https://cv.wikipedia.org/wiki/%D0%90%D1%82%D0%BE%D0%BC_%D1%82%D0%B5%D0%BE%D1%80%D0%B8%D0%B9%C4%95" title="Атом теорийĕ – Chuvash" lang="cv" hreflang="cv" data-title="Атом теорийĕ" data-language-autonym="Чӑвашла" data-language-local-name="Chuvash" class="interlanguage-link-target"><span>Чӑвашла</span></a></li><li class="interlanguage-link interwiki-cs badge-Q70893996 mw-list-item" title=""><a href="https://cs.wikipedia.org/wiki/Atomov%C3%A1_teorie" title="Atomová teorie – Czech" lang="cs" hreflang="cs" data-title="Atomová teorie" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Atomteori" title="Atomteori – Danish" lang="da" hreflang="da" data-title="Atomteori" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Liste_der_Atommodelle" title="Liste der Atommodelle – German" lang="de" hreflang="de" data-title="Liste der Atommodelle" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/Aatomimudel" title="Aatomimudel – Estonian" lang="et" hreflang="et" data-title="Aatomimudel" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target"><span>Eesti</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%91%CF%84%CE%BF%CE%BC%CE%B9%CE%BA%CE%AE_%CE%B8%CE%B5%CF%89%CF%81%CE%AF%CE%B1" title="Ατομική θεωρία – Greek" lang="el" hreflang="el" data-title="Ατομική θεωρία" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Teor%C3%ADa_at%C3%B3mica" title="Teoría atómica – Spanish" lang="es" hreflang="es" data-title="Teoría atómica" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Teoria_atomiko" title="Teoria atomiko – Basque" lang="eu" hreflang="eu" data-title="Teoria atomiko" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D9%86%D8%B8%D8%B1%DB%8C%D9%87_%D8%A7%D8%AA%D9%85%DB%8C" title="نظریه اتمی – Persian" lang="fa" hreflang="fa" data-title="نظریه اتمی" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Th%C3%A9orie_atomique" title="Théorie atomique – French" lang="fr" hreflang="fr" data-title="Théorie atomique" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ga mw-list-item"><a href="https://ga.wikipedia.org/wiki/Teoiric_adamhach" title="Teoiric adamhach – Irish" lang="ga" hreflang="ga" data-title="Teoiric adamhach" data-language-autonym="Gaeilge" data-language-local-name="Irish" class="interlanguage-link-target"><span>Gaeilge</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EC%9B%90%EC%9E%90%EB%A1%A0" title="원자론 – Korean" lang="ko" hreflang="ko" data-title="원자론" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%AA%E0%A4%B0%E0%A4%AE%E0%A4%BE%E0%A4%A3%E0%A5%81%E0%A4%B5%E0%A4%BE%E0%A4%A6" title="परमाणुवाद – Hindi" lang="hi" hreflang="hi" data-title="परमाणुवाद" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Teori_atom" title="Teori atom – Indonesian" lang="id" hreflang="id" data-title="Teori atom" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%94%D7%AA%D7%95%D7%A8%D7%94_%D7%94%D7%90%D7%98%D7%95%D7%9E%D7%99%D7%AA" title="התורה האטומית – Hebrew" lang="he" hreflang="he" data-title="התורה האטומית" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-kbp mw-list-item"><a href="https://kbp.wikipedia.org/wiki/P%CA%8By%CA%8B_k%C9%94t%C9%A9%C9%A9%C9%A9_y%C9%94%C9%94_l%C9%A9ma%C9%A3z%C9%A9y%C9%9B" title="Pʋyʋ kɔtɩɩɩ yɔɔ lɩmaɣzɩyɛ – Kabiye" lang="kbp" hreflang="kbp" data-title="Pʋyʋ kɔtɩɩɩ yɔɔ lɩmaɣzɩyɛ" data-language-autonym="Kabɩyɛ" data-language-local-name="Kabiye" class="interlanguage-link-target"><span>Kabɩyɛ</span></a></li><li class="interlanguage-link interwiki-kn mw-list-item"><a href="https://kn.wikipedia.org/wiki/%E0%B2%AA%E0%B2%B0%E0%B2%AE%E0%B2%BE%E0%B2%A3%E0%B3%81_%E0%B2%B8%E0%B2%BF%E0%B2%A6%E0%B3%8D%E0%B2%A7%E0%B2%BE%E0%B2%82%E0%B2%A4" title="ಪರಮಾಣು ಸಿದ್ಧಾಂತ – Kannada" lang="kn" hreflang="kn" data-title="ಪರಮಾಣು ಸಿದ್ಧಾಂತ" data-language-autonym="ಕನ್ನಡ" data-language-local-name="Kannada" class="interlanguage-link-target"><span>ಕನ್ನಡ</span></a></li><li class="interlanguage-link interwiki-ka mw-list-item"><a href="https://ka.wikipedia.org/wiki/%E1%83%90%E1%83%A2%E1%83%9D%E1%83%9B%E1%83%A3%E1%83%A0%E1%83%98_%E1%83%97%E1%83%94%E1%83%9D%E1%83%A0%E1%83%98%E1%83%90" title="ატომური თეორია – Georgian" lang="ka" hreflang="ka" data-title="ატომური თეორია" data-language-autonym="ქართული" data-language-local-name="Georgian" class="interlanguage-link-target"><span>ქართული</span></a></li><li class="interlanguage-link interwiki-lfn mw-list-item"><a href="https://lfn.wikipedia.org/wiki/Teoria_atomal" title="Teoria atomal – Lingua Franca Nova" lang="lfn" hreflang="lfn" data-title="Teoria atomal" data-language-autonym="Lingua Franca Nova" data-language-local-name="Lingua Franca Nova" class="interlanguage-link-target"><span>Lingua Franca Nova</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/Atomelm%C3%A9let" title="Atomelmélet – Hungarian" lang="hu" hreflang="hu" data-title="Atomelmélet" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-ml mw-list-item"><a href="https://ml.wikipedia.org/wiki/%E0%B4%85%E0%B4%A3%E0%B5%81%E0%B4%B8%E0%B4%BF%E0%B4%A6%E0%B5%8D%E0%B4%A7%E0%B4%BE%E0%B4%A8%E0%B5%8D%E0%B4%A4%E0%B4%82" title="അണുസിദ്ധാന്തം – Malayalam" lang="ml" hreflang="ml" data-title="അണുസിദ്ധാന്തം" data-language-autonym="മലയാളം" data-language-local-name="Malayalam" class="interlanguage-link-target"><span>മലയാളം</span></a></li><li class="interlanguage-link interwiki-nl badge-Q70894304 mw-list-item" title=""><a href="https://nl.wikipedia.org/wiki/Atoomtheorie" title="Atoomtheorie – Dutch" lang="nl" hreflang="nl" data-title="Atoomtheorie" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E5%8E%9F%E5%AD%90%E6%A8%A1%E5%9E%8B" title="原子模型 – Japanese" lang="ja" hreflang="ja" data-title="原子模型" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Atomteori" title="Atomteori – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Atomteori" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Atomteori" title="Atomteori – Norwegian Nynorsk" lang="nn" hreflang="nn" data-title="Atomteori" data-language-autonym="Norsk nynorsk" data-language-local-name="Norwegian Nynorsk" class="interlanguage-link-target"><span>Norsk nynorsk</span></a></li><li class="interlanguage-link interwiki-uz mw-list-item"><a href="https://uz.wikipedia.org/wiki/Atom_nazariyasi" title="Atom nazariyasi – Uzbek" lang="uz" hreflang="uz" data-title="Atom nazariyasi" data-language-autonym="Oʻzbekcha / ўзбекча" data-language-local-name="Uzbek" class="interlanguage-link-target"><span>Oʻzbekcha / ўзбекча</span></a></li><li class="interlanguage-link interwiki-pa mw-list-item"><a href="https://pa.wikipedia.org/wiki/%E0%A8%AA%E0%A9%8D%E0%A8%B0%E0%A8%AE%E0%A8%BE%E0%A8%A3%E0%A9%82_%E0%A8%B8%E0%A8%BF%E0%A8%A7%E0%A8%BE%E0%A8%82%E0%A8%A4" title="ਪ੍ਰਮਾਣੂ ਸਿਧਾਂਤ – Punjabi" lang="pa" hreflang="pa" data-title="ਪ੍ਰਮਾਣੂ ਸਿਧਾਂਤ" data-language-autonym="ਪੰਜਾਬੀ" data-language-local-name="Punjabi" class="interlanguage-link-target"><span>ਪੰਜਾਬੀ</span></a></li><li class="interlanguage-link interwiki-pnb mw-list-item"><a href="https://pnb.wikipedia.org/wiki/%D8%A7%DB%8C%D9%B9%D9%85%DB%8C_%D9%86%D8%B8%D8%B1%DB%8C%DB%81" title="ایٹمی نظریہ – Western Punjabi" lang="pnb" hreflang="pnb" data-title="ایٹمی نظریہ" data-language-autonym="پنجابی" data-language-local-name="Western Punjabi" class="interlanguage-link-target"><span>پنجابی</span></a></li><li class="interlanguage-link interwiki-ps mw-list-item"><a href="https://ps.wikipedia.org/wiki/%D8%A7%D8%AA%D9%88%D9%85%D9%8A_%D8%AA%DB%8C%D9%88%D8%B1%D9%8A/%D9%86%D8%B8%D8%B1%DB%8C%D9%87" title="اتومي تیوري/نظریه – Pashto" lang="ps" hreflang="ps" data-title="اتومي تیوري/نظریه" data-language-autonym="پښتو" data-language-local-name="Pashto" class="interlanguage-link-target"><span>پښتو</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Teoria_at%C3%B4mica" title="Teoria atômica – Portuguese" lang="pt" hreflang="pt" data-title="Teoria atômica" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Teoria_atomic%C4%83" title="Teoria atomică – Romanian" lang="ro" hreflang="ro" data-title="Teoria atomică" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target"><span>Română</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%90%D1%82%D0%BE%D0%BC%D0%BD%D0%B0%D1%8F_%D1%82%D0%B5%D0%BE%D1%80%D0%B8%D1%8F" title="Атомная теория – Russian" lang="ru" hreflang="ru" data-title="Атомная теория" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-si mw-list-item"><a href="https://si.wikipedia.org/wiki/%E0%B6%B4%E0%B6%BB%E0%B6%B8%E0%B7%8F%E0%B6%AB%E0%B7%94%E0%B6%9A_%E0%B7%80%E0%B7%8F%E0%B6%AF%E0%B6%BA" title="පරමාණුක වාදය – Sinhala" lang="si" hreflang="si" data-title="පරමාණුක වාදය" data-language-autonym="සිංහල" data-language-local-name="Sinhala" class="interlanguage-link-target"><span>සිංහල</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Atomic_theory" title="Atomic theory – Simple English" lang="en-simple" hreflang="en-simple" data-title="Atomic theory" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-ckb mw-list-item"><a href="https://ckb.wikipedia.org/wiki/%D8%AA%DB%8C%DB%86%D8%B1%DB%8C%DB%8C_%D8%A6%DB%95%D8%AA%DB%86%D9%85%DB%8C" title="تیۆریی ئەتۆمی – Central Kurdish" lang="ckb" hreflang="ckb" data-title="تیۆریی ئەتۆمی" data-language-autonym="کوردی" data-language-local-name="Central Kurdish" class="interlanguage-link-target"><span>کوردی</span></a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/%D0%90%D1%82%D0%BE%D0%BC%D0%B8%D1%81%D1%82%D0%B8%D0%BA%D0%B0" title="Атомистика – Serbian" lang="sr" hreflang="sr" data-title="Атомистика" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-sh mw-list-item"><a href="https://sh.wikipedia.org/wiki/Atomska_teorija" title="Atomska teorija – Serbo-Croatian" lang="sh" hreflang="sh" data-title="Atomska teorija" data-language-autonym="Srpskohrvatski / српскохрватски" data-language-local-name="Serbo-Croatian" class="interlanguage-link-target"><span>Srpskohrvatski / српскохрватски</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/Atomiteoria" title="Atomiteoria – Finnish" lang="fi" hreflang="fi" data-title="Atomiteoria" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Atomteori" title="Atomteori – Swedish" lang="sv" hreflang="sv" data-title="Atomteori" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-tl mw-list-item"><a href="https://tl.wikipedia.org/wiki/Hinuhang_atomiko" title="Hinuhang atomiko – Tagalog" lang="tl" hreflang="tl" data-title="Hinuhang atomiko" data-language-autonym="Tagalog" data-language-local-name="Tagalog" class="interlanguage-link-target"><span>Tagalog</span></a></li><li class="interlanguage-link interwiki-ta mw-list-item"><a href="https://ta.wikipedia.org/wiki/%E0%AE%85%E0%AE%A3%E0%AF%81%E0%AE%95%E0%AF%8D_%E0%AE%95%E0%AF%8B%E0%AE%9F%E0%AF%8D%E0%AE%AA%E0%AE%BE%E0%AE%9F%E0%AF%81" title="அணுக் கோட்பாடு – Tamil" lang="ta" hreflang="ta" data-title="அணுக் கோட்பாடு" data-language-autonym="தமிழ்" data-language-local-name="Tamil" class="interlanguage-link-target"><span>தமிழ்</span></a></li><li class="interlanguage-link interwiki-te mw-list-item"><a href="https://te.wikipedia.org/wiki/%E0%B0%AA%E0%B0%B0%E0%B0%AE%E0%B0%BE%E0%B0%A3%E0%B1%81_%E0%B0%B8%E0%B0%BF%E0%B0%A6%E0%B1%8D%E0%B0%A7%E0%B0%BE%E0%B0%82%E0%B0%A4%E0%B0%82" title="పరమాణు సిద్ధాంతం – Telugu" lang="te" hreflang="te" data-title="పరమాణు సిద్ధాంతం" data-language-autonym="తెలుగు" data-language-local-name="Telugu" class="interlanguage-link-target"><span>తెలుగు</span></a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B8%97%E0%B8%A4%E0%B8%A9%E0%B8%8E%E0%B8%B5%E0%B8%AD%E0%B8%B0%E0%B8%95%E0%B8%AD%E0%B8%A1" title="ทฤษฎีอะตอม – Thai" lang="th" hreflang="th" data-title="ทฤษฎีอะตอม" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target"><span>ไทย</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Atom_teorisi" title="Atom teorisi – Turkish" lang="tr" hreflang="tr" data-title="Atom teorisi" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%90%D1%82%D0%BE%D0%BC%D0%BD%D0%B0_%D1%82%D0%B5%D0%BE%D1%80%D1%96%D1%8F" title="Атомна теорія – Ukrainian" lang="uk" hreflang="uk" data-title="Атомна теорія" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-ur mw-list-item"><a href="https://ur.wikipedia.org/wiki/%D9%86%D8%B8%D8%B1%DB%8C%DB%82_%D8%AC%D9%88%DB%81%D8%B1" title="نظریۂ جوہر – Urdu" lang="ur" hreflang="ur" data-title="نظریۂ جوہر" data-language-autonym="اردو" data-language-local-name="Urdu" class="interlanguage-link-target"><span>اردو</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/Thuy%E1%BA%BFt_nguy%C3%AAn_t%E1%BB%AD" title="Thuyết nguyên tử – Vietnamese" lang="vi" hreflang="vi" data-title="Thuyết nguyên tử" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-fiu-vro mw-list-item"><a href="https://fiu-vro.wikipedia.org/wiki/Aadomiteooria" title="Aadomiteooria – Võro" lang="vro" hreflang="vro" data-title="Aadomiteooria" data-language-autonym="Võro" data-language-local-name="Võro" class="interlanguage-link-target"><span>Võro</span></a></li><li class="interlanguage-link interwiki-war mw-list-item"><a href="https://war.wikipedia.org/wiki/Teyorya_atomika" title="Teyorya atomika – Waray" lang="war" hreflang="war" data-title="Teyorya atomika" data-language-autonym="Winaray" data-language-local-name="Waray" class="interlanguage-link-target"><span>Winaray</span></a></li><li class="interlanguage-link interwiki-wuu mw-list-item"><a href="https://wuu.wikipedia.org/wiki/%E5%8E%9F%E5%AD%90%E7%90%86%E8%AE%BA" title="原子理论 – Wu" lang="wuu" hreflang="wuu" data-title="原子理论" data-language-autonym="吴语" data-language-local-name="Wu" class="interlanguage-link-target"><span>吴语</span></a></li><li class="interlanguage-link interwiki-zh-yue mw-list-item"><a href="https://zh-yue.wikipedia.org/wiki/%E5%8E%9F%E5%AD%90%E8%AB%96" title="原子論 – Cantonese" lang="yue" hreflang="yue" data-title="原子論" data-language-autonym="粵語" data-language-local-name="Cantonese" class="interlanguage-link-target"><span>粵語</span></a></li><li class="interlanguage-link interwiki-zh badge-Q17437798 badge-goodarticle mw-list-item" title="good article badge"><a href="https://zh.wikipedia.org/wiki/%E5%8E%9F%E5%AD%90%E7%90%86%E8%AB%96" title="原子理論 – Chinese" lang="zh" hreflang="zh" data-title="原子理論" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q210553#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespaces"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-nstab-main" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/History_of_atomic_theory" title="View the content page [c]" accesskey="c"><span>Article</span></a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/Talk:History_of_atomic_theory" rel="discussion" title="Discuss improvements to the content page [t]" accesskey="t"><span>Talk</span></a></li> </ul> </div> </div> <div id="vector-variants-dropdown" class="vector-dropdown emptyPortlet" > <input type="checkbox" id="vector-variants-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-variants-dropdown" class="vector-dropdown-checkbox " aria-label="Change language variant" > <label id="vector-variants-dropdown-label" for="vector-variants-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">English</span> </label> <div class="vector-dropdown-content"> <div id="p-variants" class="vector-menu mw-portlet mw-portlet-variants emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> </div> </div> </nav> </div> <div id="right-navigation" class="vector-collapsible"> <nav aria-label="Views"> <div id="p-views" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-views" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-view" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/History_of_atomic_theory"><span>Read</span></a></li><li id="ca-viewsource" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=History_of_atomic_theory&action=edit" title="This page is protected.
You can view its source [e]" accesskey="e"><span>View source</span></a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=History_of_atomic_theory&action=history" title="Past revisions of this page [h]" accesskey="h"><span>View history</span></a></li> </ul> </div> </div> </nav> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-dropdown" class="vector-dropdown vector-page-tools-dropdown" > <input type="checkbox" id="vector-page-tools-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-tools-dropdown" class="vector-dropdown-checkbox " aria-label="Tools" > <label id="vector-page-tools-dropdown-label" for="vector-page-tools-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">Tools</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-tools-unpinned-container" class="vector-unpinned-container"> <div id="vector-page-tools" class="vector-page-tools vector-pinnable-element"> <div class="vector-pinnable-header vector-page-tools-pinnable-header vector-pinnable-header-unpinned" data-feature-name="page-tools-pinned" data-pinnable-element-id="vector-page-tools" data-pinned-container-id="vector-page-tools-pinned-container" data-unpinned-container-id="vector-page-tools-unpinned-container" > <div class="vector-pinnable-header-label">Tools</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-page-tools.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-page-tools.unpin">hide</button> </div> <div id="p-cactions" class="vector-menu mw-portlet mw-portlet-cactions emptyPortlet vector-has-collapsible-items" title="More options" > <div class="vector-menu-heading"> Actions </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-more-view" class="selected vector-more-collapsible-item mw-list-item"><a href="/wiki/History_of_atomic_theory"><span>Read</span></a></li><li id="ca-more-viewsource" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=History_of_atomic_theory&action=edit"><span>View source</span></a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=History_of_atomic_theory&action=history"><span>View history</span></a></li> </ul> </div> </div> <div id="p-tb" class="vector-menu mw-portlet mw-portlet-tb" > <div class="vector-menu-heading"> General </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-whatlinkshere" class="mw-list-item"><a href="/wiki/Special:WhatLinksHere/History_of_atomic_theory" title="List of all English Wikipedia pages containing links to this page [j]" accesskey="j"><span>What links here</span></a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/Special:RecentChangesLinked/History_of_atomic_theory" rel="nofollow" title="Recent changes in pages linked from this page [k]" accesskey="k"><span>Related changes</span></a></li><li id="t-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_Upload_Wizard" title="Upload files [u]" accesskey="u"><span>Upload file</span></a></li><li id="t-specialpages" class="mw-list-item"><a href="/wiki/Special:SpecialPages" title="A list of all special pages [q]" accesskey="q"><span>Special pages</span></a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=History_of_atomic_theory&oldid=1257505012" title="Permanent link to this revision of this page"><span>Permanent link</span></a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=History_of_atomic_theory&action=info" title="More information about this page"><span>Page information</span></a></li><li id="t-cite" class="mw-list-item"><a href="/w/index.php?title=Special:CiteThisPage&page=History_of_atomic_theory&id=1257505012&wpFormIdentifier=titleform" title="Information on how to cite this page"><span>Cite this page</span></a></li><li id="t-urlshortener" class="mw-list-item"><a href="/w/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FHistory_of_atomic_theory"><span>Get shortened URL</span></a></li><li id="t-urlshortener-qrcode" class="mw-list-item"><a href="/w/index.php?title=Special:QrCode&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FHistory_of_atomic_theory"><span>Download QR code</span></a></li> </ul> </div> </div> <div id="p-coll-print_export" class="vector-menu mw-portlet mw-portlet-coll-print_export" > <div class="vector-menu-heading"> Print/export </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="coll-download-as-rl" class="mw-list-item"><a href="/w/index.php?title=Special:DownloadAsPdf&page=History_of_atomic_theory&action=show-download-screen" title="Download this page as a PDF file"><span>Download as PDF</span></a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=History_of_atomic_theory&printable=yes" title="Printable version of this page [p]" accesskey="p"><span>Printable version</span></a></li> </ul> </div> </div> <div id="p-wikibase-otherprojects" class="vector-menu mw-portlet mw-portlet-wikibase-otherprojects" > <div class="vector-menu-heading"> In other projects </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="wb-otherproject-link wb-otherproject-wikiquote mw-list-item"><a href="https://en.wikiquote.org/wiki/Atomic_theory" hreflang="en"><span>Wikiquote</span></a></li><li id="t-wikibase" class="wb-otherproject-link wb-otherproject-wikibase-dataitem mw-list-item"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q210553" title="Structured data on this page hosted by Wikidata [g]" accesskey="g"><span>Wikidata item</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> </div> </div> </div> <div class="vector-column-end"> <div class="vector-sticky-pinned-container"> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-pinned-container" class="vector-pinned-container"> </div> </nav> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-pinned-container" class="vector-pinned-container"> <div id="vector-appearance" class="vector-appearance vector-pinnable-element"> <div class="vector-pinnable-header vector-appearance-pinnable-header vector-pinnable-header-pinned" data-feature-name="appearance-pinned" data-pinnable-element-id="vector-appearance" data-pinned-container-id="vector-appearance-pinned-container" data-unpinned-container-id="vector-appearance-unpinned-container" > <div class="vector-pinnable-header-label">Appearance</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-appearance.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-appearance.unpin">hide</button> </div> </div> </div> </nav> </div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> <div id="mw-indicator-good-star" class="mw-indicator"><div class="mw-parser-output"><span typeof="mw:File"><a href="/wiki/Wikipedia:Good_articles*" title="This is a good article. Click here for more information."><img alt="This is a good article. Click here for more information." src="//upload.wikimedia.org/wikipedia/en/thumb/9/94/Symbol_support_vote.svg/19px-Symbol_support_vote.svg.png" decoding="async" width="19" height="20" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/94/Symbol_support_vote.svg/29px-Symbol_support_vote.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/94/Symbol_support_vote.svg/39px-Symbol_support_vote.svg.png 2x" data-file-width="180" data-file-height="185" /></a></span></div></div> <div id="mw-indicator-pp-default" class="mw-indicator"><div class="mw-parser-output"><span typeof="mw:File"><a href="/wiki/Wikipedia:Protection_policy#semi" title="This article is semi-protected due to vandalism"><img alt="Page semi-protected" src="//upload.wikimedia.org/wikipedia/en/thumb/1/1b/Semi-protection-shackle.svg/20px-Semi-protection-shackle.svg.png" decoding="async" width="20" height="20" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/1/1b/Semi-protection-shackle.svg/30px-Semi-protection-shackle.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/1/1b/Semi-protection-shackle.svg/40px-Semi-protection-shackle.svg.png 2x" data-file-width="512" data-file-height="512" /></a></span></div></div> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"><span class="mw-redirectedfrom">(Redirected from <a href="/w/index.php?title=Atomic_theory&redirect=no" class="mw-redirect" title="Atomic theory">Atomic theory</a>)</span></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><p class="mw-empty-elt"> </p> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">"Atomic model" redirects here. For the unrelated term in mathematical logic, see <a href="/wiki/Atomic_model_(mathematical_logic)" title="Atomic model (mathematical logic)">atomic model (mathematical logic)</a>.</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">This article is about the historical development of understanding the existence and behavior of atoms. For a history of the study of how atoms combine to form molecules, see <a href="/wiki/History_of_molecular_theory" title="History of molecular theory">history of molecular theory</a>. For the modern view of the atom which developed from atomic theory, see <a href="/wiki/Atomic_physics" title="Atomic physics">atomic physics</a>.</div> <p class="mw-empty-elt"> </p> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Helium_atom_QM.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/2/23/Helium_atom_QM.svg/200px-Helium_atom_QM.svg.png" decoding="async" width="200" height="201" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/23/Helium_atom_QM.svg/300px-Helium_atom_QM.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/23/Helium_atom_QM.svg/400px-Helium_atom_QM.svg.png 2x" data-file-width="665" data-file-height="667" /></a><figcaption>The current theoretical model of the atom involves a dense nucleus surrounded by a probabilistic "cloud" of electrons</figcaption></figure> <p><b>Atomic theory</b> is the scientific theory that <a href="/wiki/Matter" title="Matter">matter</a> is composed of particles called <a href="/wiki/Atom" title="Atom">atoms</a>. The definition of the word "atom" has changed over the years in response to scientific discoveries. Initially, it referred to a hypothetical concept of there being some fundamental particle of matter, too small to be seen by the naked eye, that could not be divided. Then the definition was refined to being the basic particles of the chemical elements, when chemists observed that elements seemed to combine with each other in ratios of small whole numbers. Then physicists discovered that these particles had an internal structure of their own and therefore perhaps did not deserve to be called "atoms", but renaming atoms would have been impractical by that point. </p><p>Atomic theory is one of the most important scientific developments in history, crucial to all the physical sciences. At the start of <i><a href="/wiki/The_Feynman_Lectures_on_Physics" title="The Feynman Lectures on Physics">The Feynman Lectures on Physics</a></i>, physicist and Nobel laureate <a href="/wiki/Richard_Feynman" title="Richard Feynman">Richard Feynman</a> offers the atomic hypothesis as the single most prolific scientific concept.<sup id="cite_ref-feynmanleightonsands1963-atomic_1-0" class="reference"><a href="#cite_note-feynmanleightonsands1963-atomic-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Philosophical_atomism">Philosophical atomism</h2></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Atomism" title="Atomism">Atomism</a></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/Alchemy" title="Alchemy">Alchemy</a></div> <p>The basic idea that matter is made up of tiny indivisible particles is an old idea that appeared in many ancient cultures. The word <i>atom</i> is derived from the <a href="/wiki/Ancient_Greek" title="Ancient Greek">ancient Greek</a> word <i>atomos</i>,<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>a<span class="cite-bracket">]</span></a></sup> which means "uncuttable". This ancient idea was based in philosophical reasoning rather than scientific reasoning. Modern atomic theory is not based on these old concepts.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> In the early 19th century, the scientist <a href="/wiki/John_Dalton" title="John Dalton">John Dalton</a> noticed that <a href="/wiki/Chemical_substance" title="Chemical substance">chemical substances</a> seemed to combine with each other by discrete and consistent units of weight, and he decided to use the word <i>atom</i> to refer to these units.<sup id="cite_ref-Pullman_1998_p._201_5-0" class="reference"><a href="#cite_note-Pullman_1998_p._201-5"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Groundwork">Groundwork</h2></div> <p>Working in the late 17th century, <a href="/wiki/Robert_Boyle" title="Robert Boyle">Robert Boyle</a> developed the concept of a chemical element as substance different from a compound.<sup id="cite_ref-Whittaker_6-0" class="reference"><a href="#cite_note-Whittaker-6"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 293">: 293 </span></sup> Near the end of the 18th century, a number of important developments in chemistry emerged without referring to the notion of an atomic theory. The first was <a href="/wiki/Antoine_Lavoisier" title="Antoine Lavoisier">Antoine Lavoisier</a> who showed that compounds consist of elements in constant proportion, redefining an element as a substance which scientists could not decompose into simpler substances by experimentation. This brought an end to the ancient idea of the elements of matter being fire, earth, air, and water, which had no experimental support. Lavoisier showed that water can be decomposed into <a href="/wiki/Hydrogen" title="Hydrogen">hydrogen</a> and <a href="/wiki/Oxygen" title="Oxygen">oxygen</a>, which in turn he could not decompose into anything simpler, thereby proving these are elements.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> Lavoisier also defined the <a href="/wiki/Law_of_conservation_of_mass" class="mw-redirect" title="Law of conservation of mass">law of conservation of mass</a>, which states that in a chemical reaction, matter does not appear nor disappear into thin air; the total mass remains the same even if the substances involved were transformed.<sup id="cite_ref-Whittaker_6-1" class="reference"><a href="#cite_note-Whittaker-6"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 293">: 293 </span></sup> Finally, there was the <a href="/wiki/Law_of_definite_proportions" title="Law of definite proportions">law of definite proportions</a>, established by the French chemist <a href="/wiki/Joseph_Proust" title="Joseph Proust">Joseph Proust</a> in 1797, which states that if a compound is broken down into its constituent chemical elements, then the masses of those constituents will always have the same proportions by weight, regardless of the quantity or source of the original compound. This definition distinguished compounds from mixtures.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Dalton's_law_of_multiple_proportions"><span id="Dalton.27s_law_of_multiple_proportions"></span><span class="anchor" id="Dalton"></span>Dalton's law of multiple proportions</h2></div> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Daltons_symbols.gif" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/3/39/Daltons_symbols.gif/220px-Daltons_symbols.gif" decoding="async" width="220" height="191" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/39/Daltons_symbols.gif/330px-Daltons_symbols.gif 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/39/Daltons_symbols.gif/440px-Daltons_symbols.gif 2x" data-file-width="1067" data-file-height="928" /></a><figcaption>From <i>A New System of Chemical Philosophy</i> (John Dalton 1808).</figcaption></figure> <p><a href="/wiki/John_Dalton" title="John Dalton">John Dalton</a> studied data gathered by himself and by other scientists. He noticed a pattern that later came to be known as the <a href="/wiki/Law_of_multiple_proportions" title="Law of multiple proportions">law of multiple proportions</a>: in compounds which contain two particular elements, the amount of Element A per measure of Element B will differ across these compounds by ratios of small whole numbers. This suggested that each element combines with other elements in multiples of a basic quantity.<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> </p><p>In 1804, Dalton explained his atomic theory to his friend and fellow chemist <a href="/wiki/Thomas_Thomson_(chemist)" title="Thomas Thomson (chemist)">Thomas Thomson</a>, who published an explanation of Dalton's theory in his book <i>A System of Chemistry</i> in 1807. According to Thomson, Dalton's idea first occurred to him when experimenting with "olefiant gas" (<a href="/wiki/Ethylene" title="Ethylene">ethylene</a>) and "carburetted hydrogen gas" (<a href="/wiki/Methane" title="Methane">methane</a>). Dalton found that "carburetted hydrogen gas" contains twice as much hydrogen per measure of carbon as "olefiant gas", and concluded that a molecule of "olefiant gas" is one carbon atom and one hydrogen atom, and a molecule of "carburetted hydrogen gas" is one carbon atom and two hydrogen atoms.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> In reality, an <a href="/wiki/Ethylene" title="Ethylene">ethylene</a> molecule has two carbon atoms and four hydrogen atoms (C<sub>2</sub>H<sub>4</sub>), and a <a href="/wiki/Methane" title="Methane">methane</a> molecule has one carbon atom and four hydrogen atoms (CH<sub>4</sub>). In this particular case, Dalton was mistaken about the formulas of these compounds, and it wasn't his only mistake. But in other cases, he got their formulas right, as in the following examples: </p><p><i><b>Example 1 — tin oxides:</b></i> Dalton identified two types of <a href="/wiki/Tin_oxide_(disambiguation)" class="mw-redirect" title="Tin oxide (disambiguation)">tin oxide</a>. One is a grey powder that Dalton referred to as "the protoxide of tin", which is 88.1% tin and 11.9% oxygen. The other is a white powder which Dalton referred to as "the deutoxide of tin", which is 78.7% tin and 21.3% oxygen. Adjusting these figures, in the grey powder there is about 13.5 g of oxygen for every 100 g of tin, and in the white powder there is about 27 g of oxygen for every 100 g of tin. 13.5 and 27 form a ratio of 1:2. These compounds are known today as <a href="/wiki/Tin(II)_oxide" title="Tin(II) oxide">tin(II) oxide</a> (SnO) and <a href="/wiki/Tin(IV)_oxide" title="Tin(IV) oxide">tin(IV) oxide</a> (SnO<sub>2</sub>).<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> In Dalton's terminology, a "protoxide" is a molecule containing a single oxygen atom, and a "deutoxide" molecule has two. The modern equivalents of his terms would be <i>monoxide</i> and <i>dioxide</i>.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> </p><p><i><b>Example 2 — iron oxides:</b></i> Dalton identified two oxides of iron. There is one type of iron oxide that is a black powder which Dalton referred to as "the protoxide of iron", which is 78.1% iron and 21.9% oxygen. The other iron oxide is a red powder, which Dalton referred to as "the intermediate or red oxide of iron" which is 70.4% iron and 29.6% oxygen. Adjusting these figures, in the black powder there is about 28 g of oxygen for every 100 g of iron, and in the red powder there is about 42 g of oxygen for every 100 g of iron. 28 and 42 form a ratio of 2:3. These compounds are <a href="/wiki/Iron(II)_oxide" title="Iron(II) oxide">iron(II) oxide</a> and <a href="/wiki/Iron(III)_oxide" title="Iron(III) oxide">iron(III) oxide</a> and their formulas are Fe<sub>2</sub>O<sub>2</sub> and Fe<sub>2</sub>O<sub>3</sub> respectively (iron(II) oxide's formula is normally written as FeO, but here it is written as Fe<sub>2</sub>O<sub>2</sub> to contrast it with the other oxide). Dalton described the "intermediate oxide" as being "2 atoms protoxide and 1 of oxygen", which adds up to two atoms of iron and three of oxygen. That averages to one and a half atoms of oxygen for every iron atom, putting it midway between a "protoxide" and a "deutoxide".<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p><p><i><b>Example 3 — nitrogen oxides:</b></i> Dalton was aware of three oxides of nitrogen: "nitrous oxide", "nitrous gas", and "nitric acid".<sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> These compounds are known today as <a href="/wiki/Nitrous_oxide" title="Nitrous oxide">nitrous oxide</a>, <a href="/wiki/Nitric_oxide" title="Nitric oxide">nitric oxide</a>, and <a href="/wiki/Nitrogen_dioxide" title="Nitrogen dioxide">nitrogen dioxide</a> respectively. "Nitrous oxide" is 63.3% nitrogen and 36.7% oxygen, which means it has 80 g of oxygen for every 140 g of nitrogen. "Nitrous gas" is 44.05% nitrogen and 55.95% oxygen, which means there is 160 g of oxygen for every 140 g of nitrogen. "Nitric acid" is 29.5% nitrogen and 70.5% oxygen, which means it has 320 g of oxygen for every 140 g of nitrogen. 80 g, 160 g, and 320 g form a ratio of 1:2:4. The formulas for these compounds are N<sub>2</sub>O, NO, and NO<sub>2</sub>.<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-19" class="reference"><a href="#cite_note-19"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup> </p><p>Dalton defined an atom as being the "ultimate particle" of a chemical substance, and he used the term "compound atom" to refer to "ultimate particles" which contain two or more elements. This is inconsistent with the modern definition, wherein an atom is the basic particle of a <a href="/wiki/Chemical_element" title="Chemical element">chemical element</a> and a molecule is an agglomeration of atoms. The term "compound atom" was confusing to some of Dalton's contemporaries as the word "atom" implies indivisibility, but he responded that if a <a href="/wiki/Carbon_dioxide" title="Carbon dioxide">carbon dioxide</a> "atom" is divided, it ceases to be carbon dioxide. The carbon dioxide "atom" is indivisible in the sense that it cannot be divided into smaller carbon dioxide particles.<sup id="cite_ref-Pullman_1998_p._201_5-1" class="reference"><a href="#cite_note-Pullman_1998_p._201-5"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-20" class="reference"><a href="#cite_note-20"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> </p><p>Dalton made the following assumptions on how "elementary atoms" combined to form "compound atoms" (what we today refer to as <a href="/wiki/Molecule" title="Molecule">molecules</a>). When two elements can only form one compound, he assumed it was one atom of each, which he called a "binary compound". If two elements can form two compounds, the first compound is a binary compound and the second is a "ternary compound" consisting of one atom of the first element and two of the second. If two elements can form three compounds between them, then the third compound is a "quaternary" compound containing one atom of the first element and three of the second.<sup id="cite_ref-21" class="reference"><a href="#cite_note-21"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> Dalton thought that water was a "binary compound", i.e. one hydrogen atom and one oxygen atom. Dalton did not know that in their natural gaseous state, the ultimate particles of oxygen, nitrogen, and hydrogen exist in pairs (O<sub>2</sub>, N<sub>2</sub>, and H<sub>2</sub>). Nor was he aware of valencies. These properties of atoms were discovered later in the 19th century.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (October 2024)">citation needed</span></a></i>]</sup> </p><p>Because atoms were too small to be directly weighed using the methods of the 19th century, Dalton instead expressed the weights of the myriad atoms as multiples of the hydrogen atom's weight, which Dalton knew was the lightest element. By his measurements, 7 grams of oxygen will combine with 1 gram of hydrogen to make 8 grams of water with nothing left over, and assuming a water molecule to be one oxygen atom and one hydrogen atom, he concluded that oxygen's atomic weight is 7. In reality it is 16. Aside from the crudity of early 19th century measurement tools, the main reason for this error was that Dalton didn't know that the water molecule in fact has two hydrogen atoms, not one. Had he known, he would have doubled his estimate to a more accurate 14. This error was corrected in 1811 by <a href="/wiki/Amedeo_Avogadro" title="Amedeo Avogadro">Amedeo Avogadro</a>. Avogadro proposed that equal volumes of any two gases, at equal temperature and pressure, contain equal numbers of molecules (in other words, the mass of a gas's particles does not affect the volume that it occupies).<sup id="cite_ref-avogadro_22-0" class="reference"><a href="#cite_note-avogadro-22"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> Avogadro's hypothesis, now usually called <a href="/wiki/Avogadro%27s_law" title="Avogadro's law">Avogadro's law</a>, provided a method for deducing the relative weights of the molecules of gaseous elements, for if the hypothesis is correct relative gas densities directly indicate the relative weights of the particles that compose the gases. This way of thinking led directly to a second hypothesis: the particles of certain elemental gases were pairs of atoms, and when reacting chemically these molecules often split in two. For instance, the fact that two liters of hydrogen will react with just one liter of oxygen to produce two liters of water vapor (at constant pressure and temperature) suggested that a single oxygen molecule splits in two in order to form two molecules of water. The formula of water is H<sub>2</sub>O, not HO. Avogadro measured oxygen's atomic weight to be 15.074.<sup id="cite_ref-23" class="reference"><a href="#cite_note-23"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Opposition_to_atomic_theory">Opposition to atomic theory</h2></div> <p>Dalton's atomic theory attracted widespread interest but not everyone accepted it at first. The law of multiple proportions was shown not to be a universal law when it came to organic substances, whose molecules can be quite large. For instance, in <a href="/wiki/Oleic_acid" title="Oleic acid">oleic acid</a> there is 34 g of hydrogen for every 216 g of carbon, and in <a href="/wiki/Methane" title="Methane">methane</a> there is 72 g of hydrogen for every 216 g of carbon. 34 and 72 form a ratio of 17:36, which is not a ratio of small whole numbers. We know now that carbon-based substances can have very large molecules, larger than any the other elements can form. Oleic acid's formula is C<sub>18</sub>H<sub>34</sub>O<sub>2</sub> and methane's is CH<sub>4</sub>.<sup id="cite_ref-24" class="reference"><a href="#cite_note-24"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup> The law of multiple proportions by itself was not complete proof, and atomic theory was not universally accepted until the end of the 19th century.<sup id="cite_ref-25" class="reference"><a href="#cite_note-25"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup> </p><p>One problem was the lack of uniform nomenclature. The word "atom" implied indivisibility, but Dalton defined an atom as being the ultimate particle of any <a href="/wiki/Chemical_substance" title="Chemical substance">chemical substance</a>, not just the elements or even matter per se. This meant that "compound atoms" such as carbon dioxide could be divided, as opposed to "elementary atoms". Dalton disliked the word "molecule", regarding it as "diminutive".<sup id="cite_ref-Pullman_1998_p._201_5-2" class="reference"><a href="#cite_note-Pullman_1998_p._201-5"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-26" class="reference"><a href="#cite_note-26"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup> <a href="/wiki/Amedeo_Avogadro" title="Amedeo Avogadro">Amedeo Avogadro</a> did the opposite: he exclusively used the word "molecule" in his writings, eschewing the word "atom", instead using the term "elementary molecule".<sup id="cite_ref-27" class="reference"><a href="#cite_note-27"><span class="cite-bracket">[</span>26<span class="cite-bracket">]</span></a></sup> <a href="/wiki/J%C3%B6ns_Jacob_Berzelius" title="Jöns Jacob Berzelius">Jöns Jacob Berzelius</a> used the term "organic atoms" to refer to particles containing three or more elements, because he thought this only existed in organic compounds. <a href="/wiki/Jean-Baptiste_Dumas" title="Jean-Baptiste Dumas">Jean-Baptiste Dumas</a> used the terms "physical atoms" and "chemical atoms"; a "physical atom" was a particle that cannot be divided by physical means such as temperature and pressure, and a "chemical atom" was a particle that could not be divided by chemical reactions.<sup id="cite_ref-28" class="reference"><a href="#cite_note-28"><span class="cite-bracket">[</span>27<span class="cite-bracket">]</span></a></sup> </p><p>The modern definitions of <i>atom</i> and <i>molecule</i>—an atom being the basic particle of an element, and a molecule being an agglomeration of atoms—were established in the late half of the 19th century. A key event was the <a href="/wiki/Karlsruhe_Congress" title="Karlsruhe Congress">Karlsruhe Congress</a> in Germany in 1860. As the first international congress of chemists, its goal was to establish some standards in the community. A major proponent of the modern distinction between atoms and molecules was <a href="/wiki/Stanislao_Cannizzaro" title="Stanislao Cannizzaro">Stanislao Cannizzaro</a>. </p> <style data-mw-deduplicate="TemplateStyles:r1244412712">.mw-parser-output .templatequote{overflow:hidden;margin:1em 0;padding:0 32px}.mw-parser-output .templatequotecite{line-height:1.5em;text-align:left;margin-top:0}@media(min-width:500px){.mw-parser-output .templatequotecite{padding-left:1.6em}}</style><blockquote class="templatequote"><p>The various quantities of a particular element involved in the constitution of different molecules are integral multiples of a fundamental quantity that always manifests itself as an indivisible entity and which must properly be named atom.</p><div class="templatequotecite">— <cite><a href="/wiki/Stanislao_Cannizzaro" title="Stanislao Cannizzaro">Stanislao Cannizzaro</a>, 1860<sup id="cite_ref-29" class="reference"><a href="#cite_note-29"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup></cite></div></blockquote> <p>Cannizzaro criticized past chemists such as <a href="/wiki/J%C3%B6ns_Jacob_Berzelius" title="Jöns Jacob Berzelius">Berzelius</a> for not accepting that the particles of certain gaseous elements are actually pairs of atoms, which led to mistakes in their formulation of certain compounds. Berzelius believed that hydrogen gas and chlorine gas particles are solitary atoms. But he observed that when one liter of hydrogen reacts with one liter of chlorine, they form two liters of <a href="/wiki/Hydrogen_chloride" title="Hydrogen chloride">hydrogen chloride</a> instead of one. Berzelius decided that Avogadro's law does not apply to compounds. Cannizzaro preached that if scientists just accepted the existence of single-element molecules, such discrepancies in their findings would be easily resolved. But Berzelius did not even have a word for that. Berzelius used the term "elementary atom" for a gas particle which contained just one element and "compound atom" for particles which contained two or more elements, but there was nothing to distinguish H<sub>2</sub> from H since Berzelius did not believe in H<sub>2</sub>. So Cannizzaro called for a redefinition so that scientists could understand that a hydrogen <i>molecule</i> can split into two <i>atoms</i> in the course of a chemical reaction.<sup id="cite_ref-30" class="reference"><a href="#cite_note-30"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup> </p><p>A second objection to atomic theory was philosophical. Scientists in the 19th century had no way of directly observing atoms. They inferred the existence of atoms through indirect observations, such as Dalton's law of multiple proportions. Some scientists, notably those who ascribed to the school of <a href="/wiki/Positivism" title="Positivism">positivism</a>, argued that scientists should not attempt to deduce the deeper reality of the universe, but only systemize what patterns they could directly observe. The anti-atomists argued that while atoms might be a useful abstraction for predicting how elements react, they do not reflect concrete reality.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (October 2024)">citation needed</span></a></i>]</sup> </p><p>Such scientists were sometimes known as "equivalentists", because they preferred the theory of <a href="/wiki/Equivalent_weight" title="Equivalent weight">equivalent weights</a>, which is a generalization of Proust's law of definite proportions. For example, 1 gram of hydrogen will combine with 8 grams of oxygen to form 9 grams of water, therefore the "equivalent weight" of oxygen is 8 grams. This position was eventually quashed by two important advancements that happened later in the 19th century: the development of the <a href="/wiki/Periodic_table" title="Periodic table">periodic table</a> and the discovery that molecules have an internal architecture that determines their properties.<sup id="cite_ref-31" class="reference"><a href="#cite_note-31"><span class="cite-bracket">[</span>30<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Isomerism">Isomerism</h2></div> <p>Scientists discovered some substances have the exact same chemical content but different properties. For instance, in 1827, <a href="/wiki/Friedrich_W%C3%B6hler" title="Friedrich Wöhler">Friedrich Wöhler</a> discovered that <a href="/wiki/Silver_fulminate" title="Silver fulminate">silver fulminate</a> and <a href="/wiki/Silver_cyanate" title="Silver cyanate">silver cyanate</a> are both 107 parts silver, 12 parts carbon, 14 parts nitrogen, and 16 parts oxygen (we now know their formulas as both AgCNO). In 1830 <a href="/wiki/J%C3%B6ns_Jacob_Berzelius" title="Jöns Jacob Berzelius">Jöns Jacob Berzelius</a> introduced the term <i>isomerism</i> to describe the phenomenon. In 1860, <a href="/wiki/Louis_Pasteur" title="Louis Pasteur">Louis Pasteur</a> hypothesized that the molecules of isomers might have the same set of atoms but in different arrangements.<sup id="cite_ref-32" class="reference"><a href="#cite_note-32"><span class="cite-bracket">[</span>31<span class="cite-bracket">]</span></a></sup> </p><p>In 1874, <a href="/wiki/Jacobus_Henricus_van_%27t_Hoff" title="Jacobus Henricus van 't Hoff">Jacobus Henricus van 't Hoff</a> proposed that the carbon atom bonds to other atoms in a tetrahedral arrangement. Working from this, he explained the structures of organic molecules in such a way that he could predict how many isomers a compound could have. Consider, for example, <a href="/wiki/Pentane" title="Pentane">pentane</a> (C<sub>5</sub>H<sub>12</sub>). In van 't Hoff's way of modelling molecules, there are three possible configurations for pentane, and scientists did go on to discover three and only three isomers of pentane.<sup id="cite_ref-33" class="reference"><a href="#cite_note-33"><span class="cite-bracket">[</span>32<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-34" class="reference"><a href="#cite_note-34"><span class="cite-bracket">[</span>33<span class="cite-bracket">]</span></a></sup> </p> <style data-mw-deduplicate="TemplateStyles:r1237032888/mw-parser-output/.tmulti">.mw-parser-output .tmulti .multiimageinner{display:flex;flex-direction:column}.mw-parser-output .tmulti .trow{display:flex;flex-direction:row;clear:left;flex-wrap:wrap;width:100%;box-sizing:border-box}.mw-parser-output .tmulti .tsingle{margin:1px;float:left}.mw-parser-output .tmulti .theader{clear:both;font-weight:bold;text-align:center;align-self:center;background-color:transparent;width:100%}.mw-parser-output .tmulti .thumbcaption{background-color:transparent}.mw-parser-output .tmulti .text-align-left{text-align:left}.mw-parser-output .tmulti .text-align-right{text-align:right}.mw-parser-output .tmulti .text-align-center{text-align:center}@media all and (max-width:720px){.mw-parser-output .tmulti .thumbinner{width:100%!important;box-sizing:border-box;max-width:none!important;align-items:center}.mw-parser-output .tmulti .trow{justify-content:center}.mw-parser-output .tmulti .tsingle{float:none!important;max-width:100%!important;box-sizing:border-box;text-align:center}.mw-parser-output .tmulti .tsingle .thumbcaption{text-align:left}.mw-parser-output .tmulti .trow>.thumbcaption{text-align:center}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .tmulti .multiimageinner img{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .tmulti .multiimageinner img{background-color:white}}</style><div class="thumb tmulti tnone center"><div class="thumbinner multiimageinner" style="width:592px;max-width:592px"><div class="trow"><div class="tsingle" style="width:278px;max-width:278px"><div class="thumbimage" style="height:132px;overflow:hidden"><span typeof="mw:File"><a href="/wiki/File:Pentane-3D-balls.png" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/8/8a/Pentane-3D-balls.png/276px-Pentane-3D-balls.png" decoding="async" width="276" height="132" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/8a/Pentane-3D-balls.png/414px-Pentane-3D-balls.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/8a/Pentane-3D-balls.png/552px-Pentane-3D-balls.png 2x" data-file-width="1125" data-file-height="538" /></a></span></div><div class="thumbcaption"><a href="/wiki/N-pentane" class="mw-redirect" title="N-pentane">n-pentane</a></div></div><div class="tsingle" style="width:173px;max-width:173px"><div class="thumbimage" style="height:132px;overflow:hidden"><span typeof="mw:File"><a href="/wiki/File:Isopentane-3D-balls.png" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/3/35/Isopentane-3D-balls.png/171px-Isopentane-3D-balls.png" decoding="async" width="171" height="132" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/35/Isopentane-3D-balls.png/257px-Isopentane-3D-balls.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/35/Isopentane-3D-balls.png/342px-Isopentane-3D-balls.png 2x" data-file-width="1100" data-file-height="849" /></a></span></div><div class="thumbcaption"><a href="/wiki/Isopentane" title="Isopentane">isopentane</a></div></div><div class="tsingle" style="width:135px;max-width:135px"><div class="thumbimage" style="height:132px;overflow:hidden"><span typeof="mw:File"><a href="/wiki/File:Neopentane-3D-balls.png" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b4/Neopentane-3D-balls.png/133px-Neopentane-3D-balls.png" decoding="async" width="133" height="132" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b4/Neopentane-3D-balls.png/200px-Neopentane-3D-balls.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b4/Neopentane-3D-balls.png/266px-Neopentane-3D-balls.png 2x" data-file-width="1100" data-file-height="1094" /></a></span></div><div class="thumbcaption"><a href="/wiki/Neopentane" title="Neopentane">neopentane</a></div></div></div><div class="trow" style="display:flex"><div class="thumbcaption"><a href="/wiki/Jacobus_Henricus_van_%27t_Hoff" title="Jacobus Henricus van 't Hoff">Jacobus Henricus van 't Hoff</a>'s way of modelling molecular structures correctly predicted the three isomers of <a href="/wiki/Pentane" title="Pentane">pentane</a> (C<sub>5</sub>H<sub>12</sub>).</div></div></div></div> <p>Isomerism was not something that could be fully explained by alternative theories to atomic theory, such as <a href="/wiki/Radical_theory" title="Radical theory">radical theory</a> and the theory of types.<sup id="cite_ref-35" class="reference"><a href="#cite_note-35"><span class="cite-bracket">[</span>34<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-36" class="reference"><a href="#cite_note-36"><span class="cite-bracket">[</span>35<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Mendeleev's_periodic_table"><span id="Mendeleev.27s_periodic_table"></span>Mendeleev's periodic table</h2></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Periodic_table" title="Periodic table">Periodic table</a></div> <p><a href="/wiki/Dmitrii_Mendeleev" class="mw-redirect" title="Dmitrii Mendeleev">Dmitrii Mendeleev</a> noticed that when he arranged the elements in a row according to their atomic weights, there was a certain periodicity to them.<sup id="cite_ref-Scerri_37-0" class="reference"><a href="#cite_note-Scerri-37"><span class="cite-bracket">[</span>36<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 117">: 117 </span></sup> For instance, the second element, <a href="/wiki/Lithium" title="Lithium">lithium</a>, had similar properties to the ninth element, <a href="/wiki/Sodium" title="Sodium">sodium</a>, and the sixteenth element, <a href="/wiki/Potassium" title="Potassium">potassium</a> — a period of seven. Likewise, <a href="/wiki/Beryllium" title="Beryllium">beryllium</a>, <a href="/wiki/Magnesium" title="Magnesium">magnesium</a>, and <a href="/wiki/Calcium" title="Calcium">calcium</a> were similar and all were seven places apart from each other on Mendeleev's table. Using these patterns, Mendeleev predicted the existence and properties of new elements, which were later discovered in nature: <a href="/wiki/Scandium" title="Scandium">scandium</a>, <a href="/wiki/Gallium" title="Gallium">gallium</a>, and <a href="/wiki/Germanium" title="Germanium">germanium</a>.<sup id="cite_ref-Scerri_37-1" class="reference"><a href="#cite_note-Scerri-37"><span class="cite-bracket">[</span>36<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 118">: 118 </span></sup> Moreover, the <a href="/wiki/Periodic_table" title="Periodic table">periodic table</a> could predict how many atoms of other elements that an atom could bond with — e.g., germanium and carbon are in <a href="/wiki/Carbon_group" title="Carbon group">the same group on the table</a> and their atoms both combine with two oxygen atoms each (GeO<sub>2</sub> and CO<sub>2</sub>). Mendeleev found these patterns validated atomic theory because it showed that the elements could be categorized by their atomic weight. Inserting a new element into the middle of a period would break the parallel between that period and the next, and would also violate Dalton's law of multiple proportions.<sup id="cite_ref-38" class="reference"><a href="#cite_note-38"><span class="cite-bracket">[</span>37<span class="cite-bracket">]</span></a></sup> </p> <figure class="mw-default-size mw-halign-center" typeof="mw:File/Thumb"><a href="/wiki/File:Mendelejevs_periodiska_system_1871.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/5/55/Mendelejevs_periodiska_system_1871.png" decoding="async" width="684" height="341" class="mw-file-element" data-file-width="684" data-file-height="341" /></a><figcaption>Mendeleev's <a href="/wiki/Periodic_table" title="Periodic table">periodic table</a> from 1871.</figcaption></figure> <p>In the modern periodic table, the periodicity of the elements mentioned above is eight rather than seven because the <a href="/wiki/Noble_gas" title="Noble gas">noble gases</a> were not known back when Mendeleev devised his table. The rows also now have different lengths (2, 8, 18, and 32) which fits with quantum theory.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (October 2024)">citation needed</span></a></i>]</sup> </p><p>The elements on the <a href="/wiki/Periodic_table" title="Periodic table">periodic table</a> were generally arranged in order of increasing atomic weight. However, in a number of places chemists chose to swap the positions of certain adjacent elements so that they appeared in a group with other elements with similar properties. For instance, <a href="/wiki/Tellurium" title="Tellurium">tellurium</a> is placed before <a href="/wiki/Iodine" title="Iodine">iodine</a> even though tellurium is heavier (127.6 vs 126.9) so that iodine can be in the same column as the other <a href="/wiki/Halogens" class="mw-redirect" title="Halogens">halogens</a>. </p> <div class="mw-heading mw-heading2"><h2 id="Statistical_mechanics">Statistical mechanics</h2></div> <p>In order to introduce the <a href="/wiki/Ideal_gas_law" title="Ideal gas law">ideal gas law</a> and statistical forms of physics, it was necessary to postulate the existence of atoms. In 1738, Swiss physicist and mathematician <a href="/wiki/Daniel_Bernoulli" title="Daniel Bernoulli">Daniel Bernoulli</a> postulated that the pressure of gases and heat were both caused by the underlying motion of molecules.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (October 2024)">citation needed</span></a></i>]</sup> </p><p>In 1860, <a href="/wiki/James_Clerk_Maxwell" title="James Clerk Maxwell">James Clerk Maxwell</a>, who was a vocal proponent of atomism, was the first to use <a href="/wiki/Statistical_mechanics" title="Statistical mechanics">statistical mechanics</a> in physics.<sup id="cite_ref-39" class="reference"><a href="#cite_note-39"><span class="cite-bracket">[</span>38<span class="cite-bracket">]</span></a></sup> <a href="/wiki/Ludwig_Boltzmann" title="Ludwig Boltzmann">Ludwig Boltzmann</a> and <a href="/wiki/Rudolf_Clausius" title="Rudolf Clausius">Rudolf Clausius</a> expanded his work on gases and the laws of <a href="/wiki/Thermodynamics" title="Thermodynamics">thermodynamics</a> especially the second law relating to entropy. In the 1870s, <a href="/wiki/Josiah_Willard_Gibbs" title="Josiah Willard Gibbs">Josiah Willard Gibbs</a> extended the laws of entropy and thermodynamics and coined the term "statistical mechanics."<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (October 2024)">citation needed</span></a></i>]</sup> </p><p>Boltzmann defended the atomistic hypothesis against major detractors from the time like <a href="/wiki/Ernst_Mach" title="Ernst Mach">Ernst Mach</a> or <a href="/wiki/Energeticism" title="Energeticism">energeticists</a> like <a href="/wiki/Wilhelm_Ostwald" title="Wilhelm Ostwald">Wilhelm Ostwald</a>, who considered that energy was the elementary quantity of reality.<sup id="cite_ref-40" class="reference"><a href="#cite_note-40"><span class="cite-bracket">[</span>39<span class="cite-bracket">]</span></a></sup> </p><p>At the beginning of the 20th century, <a href="/wiki/Albert_Einstein" title="Albert Einstein">Albert Einstein</a> independently reinvented Gibbs' laws, because they had only been printed in an obscure American journal.<sup id="cite_ref-41" class="reference"><a href="#cite_note-41"><span class="cite-bracket">[</span>40<span class="cite-bracket">]</span></a></sup> Einstein later commented that had he known of Gibbs' work, he would "not have published those papers at all, but confined myself to the treatment of some few points [that were distinct]."<sup id="cite_ref-42" class="reference"><a href="#cite_note-42"><span class="cite-bracket">[</span>41<span class="cite-bracket">]</span></a></sup> All of statistical mechanics and the laws of heat, gas, and entropy took the existence of atoms as a necessary postulate.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (October 2024)">citation needed</span></a></i>]</sup> </p> <div class="mw-heading mw-heading3"><h3 id="Brownian_motion">Brownian motion</h3></div> <p>In 1827, the British botanist <a href="/wiki/Robert_Brown_(botanist,_born_1773)" title="Robert Brown (botanist, born 1773)">Robert Brown</a> observed that dust particles inside pollen grains floating in water constantly jiggled about for no apparent reason. In 1905, Einstein theorized that this <a href="/wiki/Brownian_motion" title="Brownian motion">Brownian motion</a> was caused by the water molecules continuously knocking the grains about, and developed a mathematical model to describe it. This model was validated experimentally in 1908 by French physicist <a href="/wiki/Jean_Perrin" class="mw-redirect" title="Jean Perrin">Jean Perrin</a>, who used Einstein's equations to measure the size of atoms.<sup id="cite_ref-43" class="reference"><a href="#cite_note-43"><span class="cite-bracket">[</span>42<span class="cite-bracket">]</span></a></sup> </p> <table class="wikitable"> <caption>Kinetic diameters of various simple molecules </caption> <tbody><tr> <th>Molecule</th> <th>Perrin's measurements<sup id="cite_ref-44" class="reference"><a href="#cite_note-44"><span class="cite-bracket">[</span>43<span class="cite-bracket">]</span></a></sup></th> <th>Modern measurements </th></tr> <tr> <td>Helium</td> <td>1.7 × 10<sup>−10</sup> m</td> <td>2.6 × 10<sup>−10</sup> m </td></tr> <tr> <td>Argon</td> <td>2.7 × 10<sup>−10</sup> m</td> <td>3.4 × 10<sup>−10</sup> m </td></tr> <tr> <td>Mercury</td> <td>2.8 × 10<sup>−10</sup> m</td> <td>3 × 10<sup>−10</sup> m </td></tr> <tr> <td>Hydrogen</td> <td>2 × 10<sup>−10</sup> m</td> <td>2.89 × 10<sup>−10</sup> m </td></tr> <tr> <td>Oxygen</td> <td>2.6 × 10<sup>−10</sup> m</td> <td>3.46 × 10<sup>−10</sup> m </td></tr> <tr> <td>Nitrogen</td> <td>2.7 × 10<sup>−10</sup> m</td> <td>3.64 × 10<sup>−10</sup> m </td></tr> <tr> <td>Chlorine</td> <td>4 × 10<sup>−10</sup> m</td> <td>3.20 × 10<sup>−10</sup> m </td></tr></tbody></table> <table class="wikitable"> <caption>Atomic masses in kilograms </caption> <tbody><tr> <th>Molecule</th> <th>Perrin's measurements<sup id="cite_ref-45" class="reference"><a href="#cite_note-45"><span class="cite-bracket">[</span>44<span class="cite-bracket">]</span></a></sup></th> <th>Modern measurements </th></tr> <tr> <td>Hydrogen</td> <td>1.43 × 10<sup>−27</sup> kg</td> <td>1.66 × 10<sup>−27</sup> kg </td></tr> <tr> <td>Oxygen</td> <td>22.7 × 10<sup>−27</sup> kg</td> <td>22.8 × 10<sup>−27</sup> kg </td></tr></tbody></table> <div class="mw-heading mw-heading2"><h2 id="Discovery_of_the_electron">Discovery of the electron</h2></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main articles: <a href="/wiki/Electron" title="Electron">Electron</a> and <a href="/wiki/Plum_pudding_model" title="Plum pudding model">Plum pudding model</a></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1237032888/mw-parser-output/.tmulti"><div class="thumb tmulti tright"><div class="thumbinner multiimageinner" style="width:392px;max-width:392px"><div class="trow"><div class="tsingle" style="width:195px;max-width:195px"><div class="thumbimage" style="height:190px;overflow:hidden"><span typeof="mw:File"><a href="/wiki/File:Thomson_atom_electron_arrangements.jpg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/d/d4/Thomson_atom_electron_arrangements.jpg/193px-Thomson_atom_electron_arrangements.jpg" decoding="async" width="193" height="190" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/d4/Thomson_atom_electron_arrangements.jpg/290px-Thomson_atom_electron_arrangements.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/d4/Thomson_atom_electron_arrangements.jpg/386px-Thomson_atom_electron_arrangements.jpg 2x" data-file-width="567" data-file-height="559" /></a></span></div><div class="thumbcaption">A 1905 diagram by <a href="/wiki/J._J._Thomson" title="J. J. Thomson">J. J. Thomson</a> illustrating his hypothesized arrangements of electrons in an atom, ranging from one to eight electrons.</div></div><div class="tsingle" style="width:193px;max-width:193px"><div class="thumbimage" style="height:190px;overflow:hidden"><span typeof="mw:File"><a href="/wiki/File:Thomson_atom_seven_electrons.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b3/Thomson_atom_seven_electrons.svg/191px-Thomson_atom_seven_electrons.svg.png" decoding="async" width="191" height="191" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b3/Thomson_atom_seven_electrons.svg/287px-Thomson_atom_seven_electrons.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b3/Thomson_atom_seven_electrons.svg/382px-Thomson_atom_seven_electrons.svg.png 2x" data-file-width="297" data-file-height="297" /></a></span></div><div class="thumbcaption">The arrangement of seven electrons in a pentagonal dipyramid.</div></div></div></div></div> <p>Atoms were thought to be the smallest possible division of matter until 1899 when <a href="/wiki/J._J._Thomson" title="J. J. Thomson">J. J. Thomson</a> discovered the <a href="/wiki/Electron" title="Electron">electron</a> through his work on <a href="/wiki/Cathode_ray" title="Cathode ray">cathode rays</a>.<sup id="cite_ref-PaisInwardBound_46-0" class="reference"><a href="#cite_note-PaisInwardBound-46"><span class="cite-bracket">[</span>45<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 86">: 86 </span></sup><sup id="cite_ref-Whittaker_6-2" class="reference"><a href="#cite_note-Whittaker-6"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 364">: 364 </span></sup> </p><p>A <a href="/wiki/Crookes_tube" title="Crookes tube">Crookes tube</a> is a sealed glass container in which two <a href="/wiki/Electrode" title="Electrode">electrodes</a> are separated by a vacuum. When a <a href="/wiki/Voltage" title="Voltage">voltage</a> is applied across the electrodes, cathode rays are generated, creating a glowing patch where they strike the glass at the opposite end of the tube. Through experimentation, Thomson discovered that the rays could be deflected by <a href="/wiki/Electric_field" title="Electric field">electric fields</a> and <a href="/wiki/Magnetic_field" title="Magnetic field">magnetic fields</a>, which meant that these rays were not a form of light but were composed of very light charged particles, and their charge was negative. Thomson called these particles "corpuscles". He measured their mass-to-charge ratio to be several orders of magnitude smaller than that of the hydrogen atom, the smallest atom. This ratio was the same regardless of what the electrodes were made of and what the trace gas in the tube was.<sup id="cite_ref-thomson_47-0" class="reference"><a href="#cite_note-thomson-47"><span class="cite-bracket">[</span>46<span class="cite-bracket">]</span></a></sup> </p><p>In contrast to those corpuscles, positive ions created by electrolysis or X-ray radiation had mass-to-charge ratios that varied depending on the material of the electrodes and the type of gas in the reaction chamber, indicating they were different kinds of particles.<sup id="cite_ref-Whittaker_6-3" class="reference"><a href="#cite_note-Whittaker-6"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 363">: 363 </span></sup> </p><p>In 1898, Thomson measured the charge on ions to be roughly 6 × 10<sup>-10</sup> <a href="/wiki/Electrostatic_units" class="mw-redirect" title="Electrostatic units">electrostatic units</a> (2 × 10<sup>-19</sup> Coulombs).<sup id="cite_ref-PaisInwardBound_46-1" class="reference"><a href="#cite_note-PaisInwardBound-46"><span class="cite-bracket">[</span>45<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 85">: 85 </span></sup><sup id="cite_ref-48" class="reference"><a href="#cite_note-48"><span class="cite-bracket">[</span>47<span class="cite-bracket">]</span></a></sup> In 1899, he showed that negative electricity created by ultraviolet light landing on a metal (known now as the <a href="/wiki/Photoelectric_effect" title="Photoelectric effect">photoelectric effect</a>) has the same mass-to-charge ratio as cathode rays; then he applied his previous method for determining the charge on ions to the negative electric particles created by ultraviolet light.<sup id="cite_ref-PaisInwardBound_46-2" class="reference"><a href="#cite_note-PaisInwardBound-46"><span class="cite-bracket">[</span>45<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 86">: 86 </span></sup> By this combination he showed that electron's mass was 0.0014 times that of hydrogen ions.<sup id="cite_ref-49" class="reference"><a href="#cite_note-49"><span class="cite-bracket">[</span>48<span class="cite-bracket">]</span></a></sup> These "corpuscles" were so light yet carried so much charge that Thomson concluded they must be the basic particles of electricity, and for that reason other scientists decided that these "corpuscles" should instead be called <a href="/wiki/Electron" title="Electron">electrons</a> following an 1894 suggestion by <a href="/wiki/George_Johnstone_Stoney" title="George Johnstone Stoney">George Johnstone Stoney</a> for naming the basic unit of electrical charge.<sup id="cite_ref-50" class="reference"><a href="#cite_note-50"><span class="cite-bracket">[</span>49<span class="cite-bracket">]</span></a></sup> </p><p>In 1904, Thomson published a paper describing a new model of the atom.<sup id="cite_ref-51" class="reference"><a href="#cite_note-51"><span class="cite-bracket">[</span>50<span class="cite-bracket">]</span></a></sup> Electrons reside within atoms, and they transplant themselves from one atom to the next in a chain in the action of an electrical current. When electrons do not flow, their negative charge logically must be balanced out by some source of positive charge within the atom so as to render the atom electrically neutral. Having no clue as to the source of this positive charge, Thomson tentatively proposed that the positive charge was everywhere in the atom, the atom being shaped like a sphere—this was the mathematically simplest model to fit the available evidence (or lack of it).<sup id="cite_ref-52" class="reference"><a href="#cite_note-52"><span class="cite-bracket">[</span>51<span class="cite-bracket">]</span></a></sup> The balance of electrostatic forces would distribute the electrons throughout this sphere in a more or less even manner. Thomson further explained that <a href="/wiki/Ion" title="Ion">ions</a> are atoms that have a surplus or shortage of electrons.<sup id="cite_ref-53" class="reference"><a href="#cite_note-53"><span class="cite-bracket">[</span>52<span class="cite-bracket">]</span></a></sup> </p><p>Thomson's model is popularly known as the <a href="/wiki/Plum_pudding_model" title="Plum pudding model">plum pudding model</a>, based on the idea that the electrons are distributed throughout the sphere of positive charge with the same density as raisins in a <a href="/wiki/Plum_pudding" class="mw-redirect" title="Plum pudding">plum pudding</a>. Neither Thomson nor his colleagues ever used this analogy. It seems to have been a conceit of popular science writers.<sup id="cite_ref-54" class="reference"><a href="#cite_note-54"><span class="cite-bracket">[</span>53<span class="cite-bracket">]</span></a></sup> The analogy suggests that the positive sphere is like a solid, but Thomson likened it to a liquid, as he proposed that the electrons moved around in it in patterns governed by the electrostatic forces.<sup id="cite_ref-55" class="reference"><a href="#cite_note-55"><span class="cite-bracket">[</span>54<span class="cite-bracket">]</span></a></sup> More to the point, the positive electrification in Thomson's model was an abstraction, he did not propose anything concrete like a particle. Thomson's model was incomplete, it could not predict any of the known properties of the atom such as emission spectra or valencies. </p><p>In 1906, <a href="/wiki/Robert_A._Millikan" class="mw-redirect" title="Robert A. Millikan">Robert A. Millikan</a> and <a href="/wiki/Harvey_Fletcher" title="Harvey Fletcher">Harvey Fletcher</a> performed the <a href="/wiki/Oil_drop_experiment" title="Oil drop experiment">oil drop experiment</a> in which they measured the charge of an electron to be about -1.6 × 10<sup>-19</sup>, a value now defined as <a href="/wiki/Elementary_charge" title="Elementary charge">-1 <i>e</i></a>. Since the hydrogen ion and the electron were known to be indivisible and a hydrogen atom is neutral in charge, it followed that the positive charge in hydrogen was equal to this value, i.e. 1 <i>e</i>.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (October 2024)">citation needed</span></a></i>]</sup> </p> <div style="clear:both;" class=""></div> <div class="mw-heading mw-heading2"><h2 id="Discovery_of_the_nucleus">Discovery of the nucleus</h2></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Rutherford_scattering_experiments" title="Rutherford scattering experiments">Rutherford scattering experiments</a></div> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Geiger-Marsden_experiment_expectation_and_result.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/f/f9/Geiger-Marsden_experiment_expectation_and_result.svg/400px-Geiger-Marsden_experiment_expectation_and_result.svg.png" decoding="async" width="400" height="345" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/f9/Geiger-Marsden_experiment_expectation_and_result.svg/600px-Geiger-Marsden_experiment_expectation_and_result.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/f9/Geiger-Marsden_experiment_expectation_and_result.svg/800px-Geiger-Marsden_experiment_expectation_and_result.svg.png 2x" data-file-width="1196" data-file-height="1033" /></a><figcaption><b>The <a href="/wiki/Rutherford_scattering_experiments" title="Rutherford scattering experiments">Rutherford scattering experiments</a></b><br /> <i>Left:</i> Expected results: alpha particles passing through the plum pudding model of the atom with negligible deflection.<br /> <i>Right:</i> Observed results: a small portion of the particles were deflected by the concentrated positive charge of the nucleus.</figcaption></figure> <p>Thomson's <a href="/wiki/Plum_pudding_model" title="Plum pudding model">plum pudding model</a> was challenged in 1911 by one of his former students, <a href="/wiki/Ernest_Rutherford" title="Ernest Rutherford">Ernest Rutherford</a>, who presented a new model to explain new experimental data. The new model proposed a concentrated center of charge and mass that was later dubbed the <a href="/wiki/Atomic_nucleus" title="Atomic nucleus">atomic nucleus</a>.<sup id="cite_ref-Heilbron1968_56-0" class="reference"><a href="#cite_note-Heilbron1968-56"><span class="cite-bracket">[</span>55<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 296">: 296 </span></sup> </p><p><a href="/wiki/Ernest_Rutherford" title="Ernest Rutherford">Ernest Rutherford</a> and his colleagues <a href="/wiki/Hans_Geiger" title="Hans Geiger">Hans Geiger</a> and <a href="/wiki/Ernest_Marsden" title="Ernest Marsden">Ernest Marsden</a> came to have doubts about the Thomson model after they encountered difficulties when they tried to build an instrument to measure the charge-to-mass ratio of <a href="/wiki/Alpha_particles" class="mw-redirect" title="Alpha particles">alpha particles</a> (these are positively-charged particles emitted by certain radioactive substances such as <a href="/wiki/Radium" title="Radium">radium</a>). The alpha particles were being scattered by the air in the detection chamber, which made the measurements unreliable. Thomson had encountered a similar problem in his work on cathode rays, which he solved by creating a near-perfect vacuum in his instruments. Rutherford didn't think he'd run into this same problem because alpha particles usually have much more momentum than electrons. According to Thomson's model of the atom, the positive charge in the atom is not concentrated enough to produce an electric field strong enough to deflect an alpha particle. Yet there was scattering, so Rutherford and his colleagues decided to investigate this scattering carefully.<sup id="cite_ref-Heilbron2003p64-68_57-0" class="reference"><a href="#cite_note-Heilbron2003p64-68-57"><span class="cite-bracket">[</span>56<span class="cite-bracket">]</span></a></sup> </p><p>Between 1908 and 1913, Rutherford and his colleagues performed a series of experiments in which they bombarded thin foils of metal with a beam of alpha particles. They spotted alpha particles being deflected by angles greater than 90°. According to Thomson's model, all of the alpha particles should have passed through with negligible deflection. Rutherford deduced that the positive charge of the atom is not distributed throughout the atom's volume as Thomson believed, but is concentrated in a tiny nucleus at the center. This nucleus also carries most of the atom's mass. Only such an intense concentration of charge, anchored by its high mass, could produce an electric field strong enough to deflect the alpha particles as observed.<sup id="cite_ref-Heilbron2003p64-68_57-1" class="reference"><a href="#cite_note-Heilbron2003p64-68-57"><span class="cite-bracket">[</span>56<span class="cite-bracket">]</span></a></sup> Rutherford's model, being supported primarily by scattering data unfamiliar to many scientists, did not catch on until Niels Bohr joined Rutherford's lab and developed a new model for the electrons.<sup id="cite_ref-Heilbron1968_56-1" class="reference"><a href="#cite_note-Heilbron1968-56"><span class="cite-bracket">[</span>55<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 304">: 304 </span></sup> </p><p>Rutherford found that the scattering of alpha particles was roughly related to half of the atomic weight of the foil's material (gold, aluminium, etc.). Amateur physicist <a href="/wiki/Antonius_van_den_Broek" title="Antonius van den Broek">Antonius van den Broek</a> noted that there was a more precise relation between the scattering and the element's position the <a href="/wiki/Periodic_table" title="Periodic table">periodic table</a>.<sup id="cite_ref-58" class="reference"><a href="#cite_note-58"><span class="cite-bracket">[</span>57<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-59" class="reference"><a href="#cite_note-59"><span class="cite-bracket">[</span>58<span class="cite-bracket">]</span></a></sup> </p> <div style="clear:both;" class=""></div> <div class="mw-heading mw-heading2"><h2 id="Bohr_model">Bohr model</h2></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Bohr_model" title="Bohr model">Bohr model</a></div> <p>Rutherford deduced the existence of the atomic nucleus through his experiments but he had nothing to say about how the electrons were arranged around it, and this presented some issues. The first is that electrons are charged particles. An accelerating <a href="/wiki/Electric_charge" title="Electric charge">electric charge</a> is known to emit <a href="/wiki/Electromagnetic_wave" class="mw-redirect" title="Electromagnetic wave">electromagnetic waves</a> according to the <a href="/wiki/Larmor_formula" title="Larmor formula">Larmor formula</a> in <a href="/wiki/Classical_electromagnetism" title="Classical electromagnetism">classical electromagnetism</a>. Although Rutherford did not explicitly suggest that the electrons orbit the nucleus like planets, they must have some circular motion, and circular motion is acceleration. Therefore, the electrons should keep losing energy until they spiral into the nucleus. This was obviously not happening. A second issue was to find something that could explain the <a href="/wiki/Emission_spectrum" title="Emission spectrum">emission</a> and <a href="/wiki/Absorption_spectrum" class="mw-redirect" title="Absorption spectrum">absorption spectra</a> of atoms.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (October 2024)">citation needed</span></a></i>]</sup> </p> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Bohr_atom_animation_2.gif" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/1/17/Bohr_atom_animation_2.gif/220px-Bohr_atom_animation_2.gif" decoding="async" width="220" height="160" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/1/17/Bohr_atom_animation_2.gif 1.5x" data-file-width="275" data-file-height="200" /></a><figcaption>The <a href="/wiki/Bohr_model" title="Bohr model">Bohr model</a> of the atom</figcaption></figure> <p><a href="/wiki/Quantum_mechanics" title="Quantum mechanics">Quantum theory</a> revolutionized physics at the beginning of the 20th century, when <a href="/wiki/Max_Planck" title="Max Planck">Max Planck</a> and <a href="/wiki/Albert_Einstein" title="Albert Einstein">Albert Einstein</a> postulated that light energy is emitted or absorbed in discrete amounts known as <a href="/wiki/Quantum" title="Quantum">quanta</a> (singular, <i>quantum</i>). This led to a series of quantum atomic models such as the quantum model of <a href="/wiki/Arthur_Erich_Haas" title="Arthur Erich Haas">Arthur Erich Haas</a> in 1910 and the 1912 <a href="/wiki/John_William_Nicholson" title="John William Nicholson">John William Nicholson</a> quantum atomic model that quantized angular momentum as <i>h</i>/2<span class="texhtml mvar" style="font-style:italic;">π</span>.<sup id="cite_ref-60" class="reference"><a href="#cite_note-60"><span class="cite-bracket">[</span>59<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-61" class="reference"><a href="#cite_note-61"><span class="cite-bracket">[</span>60<span class="cite-bracket">]</span></a></sup> In 1913, <a href="/wiki/Niels_Bohr" title="Niels Bohr">Niels Bohr</a> incorporated this idea into his <a href="/wiki/Bohr_model" title="Bohr model">Bohr model</a> of the atom, in which an electron could only orbit the nucleus in particular circular orbits with fixed <a href="/wiki/Angular_momentum" title="Angular momentum">angular momentum</a> and energy, its distance from the nucleus (i.e., their radii) being proportional to its energy.<sup id="cite_ref-NBohr_62-0" class="reference"><a href="#cite_note-NBohr-62"><span class="cite-bracket">[</span>61<span class="cite-bracket">]</span></a></sup> Under this model an electron could not spiral into the nucleus because it could not lose energy in a continuous manner; instead, it could only make instantaneous "<a href="/wiki/Atomic_electron_transition" title="Atomic electron transition">quantum leaps</a>" between the fixed <a href="/wiki/Energy_level" title="Energy level">energy levels</a>.<sup id="cite_ref-NBohr_62-1" class="reference"><a href="#cite_note-NBohr-62"><span class="cite-bracket">[</span>61<span class="cite-bracket">]</span></a></sup> When this occurred, light was emitted or absorbed at a frequency proportional to the change in energy (hence the absorption and emission of light in discrete spectra).<sup id="cite_ref-NBohr_62-2" class="reference"><a href="#cite_note-NBohr-62"><span class="cite-bracket">[</span>61<span class="cite-bracket">]</span></a></sup> </p><p>Bohr's model was not perfect. It could only predict the <a href="/wiki/Spectral_line" title="Spectral line">spectral lines</a> of hydrogen, not those of multielectron atoms.<sup id="cite_ref-63" class="reference"><a href="#cite_note-63"><span class="cite-bracket">[</span>62<span class="cite-bracket">]</span></a></sup> Worse still, it could not even account for all features of the hydrogen spectrum: as <a href="/wiki/Spectrophotometry" title="Spectrophotometry">spectrographic technology</a> improved, it was discovered that applying a magnetic field <a href="/wiki/Zeeman_effect" title="Zeeman effect">caused spectral lines to multiply</a> in a way that Bohr's model couldn't explain. In 1916, <a href="/wiki/Arnold_Sommerfeld" title="Arnold Sommerfeld">Arnold Sommerfeld</a> added elliptical orbits to the Bohr model to explain the extra emission lines, but this made the model very difficult to use, and it still couldn't explain more complex atoms.<sup id="cite_ref-64" class="reference"><a href="#cite_note-64"><span class="cite-bracket">[</span>63<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-65" class="reference"><a href="#cite_note-65"><span class="cite-bracket">[</span>64<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Discovery_of_isotopes">Discovery of isotopes</h2></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Isotope" title="Isotope">Isotope</a></div> <p>While experimenting with the products of <a href="/wiki/Radioactive_decay" title="Radioactive decay">radioactive decay</a>, in 1913 <a href="/wiki/Radiochemistry" title="Radiochemistry">radiochemist</a> <a href="/wiki/Frederick_Soddy" title="Frederick Soddy">Frederick Soddy</a> discovered that there appeared to be more than one variety of some elements.<sup id="cite_ref-66" class="reference"><a href="#cite_note-66"><span class="cite-bracket">[</span>65<span class="cite-bracket">]</span></a></sup> The term <a href="/wiki/Isotope" title="Isotope">isotope</a> was coined by <a href="/wiki/Margaret_Todd_(doctor)" title="Margaret Todd (doctor)">Margaret Todd</a> as a suitable name for these varieties.<sup id="cite_ref-67" class="reference"><a href="#cite_note-67"><span class="cite-bracket">[</span>66<span class="cite-bracket">]</span></a></sup> </p><p>That same year, <a href="/wiki/J._J._Thomson" title="J. J. Thomson">J. J. Thomson</a> conducted an experiment in which he channeled a stream of <a href="/wiki/Neon" title="Neon">neon</a> <a href="/wiki/Ion" title="Ion">ions</a> through magnetic and electric fields, striking a photographic plate at the other end. He observed two glowing patches on the plate, which suggested two different deflection trajectories. Thomson concluded this was because some of the neon ions had a different mass.<sup id="cite_ref-thompson3_68-0" class="reference"><a href="#cite_note-thompson3-68"><span class="cite-bracket">[</span>67<span class="cite-bracket">]</span></a></sup> The nature of this differing mass would later be explained by the discovery of <a href="/wiki/Neutron" title="Neutron">neutrons</a> in 1932: all atoms of the same element contain the same number of protons, while different isotopes have different numbers of neutrons.<sup id="cite_ref-69" class="reference"><a href="#cite_note-69"><span class="cite-bracket">[</span>68<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Discovery_of_the_proton">Discovery of the proton</h2></div> <style data-mw-deduplicate="TemplateStyles:r1251242444">.mw-parser-output .ambox{border:1px solid #a2a9b1;border-left:10px solid #36c;background-color:#fbfbfb;box-sizing:border-box}.mw-parser-output .ambox+link+.ambox,.mw-parser-output .ambox+link+style+.ambox,.mw-parser-output .ambox+link+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+style+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+link+.ambox{margin-top:-1px}html body.mediawiki .mw-parser-output .ambox.mbox-small-left{margin:4px 1em 4px 0;overflow:hidden;width:238px;border-collapse:collapse;font-size:88%;line-height:1.25em}.mw-parser-output .ambox-speedy{border-left:10px solid #b32424;background-color:#fee7e6}.mw-parser-output .ambox-delete{border-left:10px solid #b32424}.mw-parser-output .ambox-content{border-left:10px solid #f28500}.mw-parser-output .ambox-style{border-left:10px solid #fc3}.mw-parser-output .ambox-move{border-left:10px solid #9932cc}.mw-parser-output .ambox-protection{border-left:10px solid #a2a9b1}.mw-parser-output .ambox .mbox-text{border:none;padding:0.25em 0.5em;width:100%}.mw-parser-output .ambox .mbox-image{border:none;padding:2px 0 2px 0.5em;text-align:center}.mw-parser-output .ambox .mbox-imageright{border:none;padding:2px 0.5em 2px 0;text-align:center}.mw-parser-output .ambox .mbox-empty-cell{border:none;padding:0;width:1px}.mw-parser-output .ambox .mbox-image-div{width:52px}@media(min-width:720px){.mw-parser-output .ambox{margin:0 10%}}@media print{body.ns-0 .mw-parser-output .ambox{display:none!important}}</style><table class="box-Prose plainlinks metadata ambox ambox-style ambox-Prose" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/f/f2/Edit-clear.svg/40px-Edit-clear.svg.png" decoding="async" width="40" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/f/f2/Edit-clear.svg/60px-Edit-clear.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/f/f2/Edit-clear.svg/80px-Edit-clear.svg.png 2x" data-file-width="48" data-file-height="48" /></span></span></div></td><td class="mbox-text"><div class="mbox-text-span">This section <b>is in <a href="/wiki/MOS:LIST" class="mw-redirect" title="MOS:LIST">list</a> format but may read better as <a href="/wiki/MOS:PROSE" class="mw-redirect" title="MOS:PROSE">prose</a></b>.<span class="hide-when-compact"> You can help by <a class="external text" href="https://en.wikipedia.org/w/index.php?title=History_of_atomic_theory&action=edit">converting this section</a>, if appropriate. <a href="/wiki/Help:Editing" title="Help:Editing">Editing help</a> is available.</span> <span class="date-container"><i>(<span class="date">November 2024</span>)</i></span></div></td></tr></tbody></table> <p>Back in 1815, <a href="/wiki/William_Prout" title="William Prout">William Prout</a> observed that the atomic weights of the known elements were multiples of hydrogen's atomic weight, so he hypothesized that all atoms are agglomerations of hydrogen, a particle which he dubbed "the protyle". <a href="/wiki/Prout%27s_hypothesis" title="Prout's hypothesis">Prout's hypothesis</a> was put into doubt when some elements were found to deviate from this pattern—e.g. chlorine atoms on average weigh 35.45 <a href="/wiki/Dalton_(unit)" title="Dalton (unit)">daltons</a>—but when <a href="/wiki/Isotopes" class="mw-redirect" title="Isotopes">isotopes</a> were discovered in 1913, Prout's observation gained renewed attention.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (October 2024)">citation needed</span></a></i>]</sup> </p><p>In 1898, J. J. Thomson found that the positive charge of a hydrogen ion was equal to the negative charge of a single electron.<sup id="cite_ref-70" class="reference"><a href="#cite_note-70"><span class="cite-bracket">[</span>69<span class="cite-bracket">]</span></a></sup> </p><p>In an April 1911 paper concerning his studies on <a href="/wiki/Alpha_particle" title="Alpha particle">alpha particle</a> scattering, <a href="/wiki/Ernest_Rutherford" title="Ernest Rutherford">Ernest Rutherford</a> estimated that the charge of an atomic nucleus, expressed as a multiplier of hydrogen's nuclear charge (<i>q</i><sub>e</sub>), is roughly half the atom's <a href="/wiki/Atomic_weight" class="mw-redirect" title="Atomic weight">atomic weight</a>.<sup id="cite_ref-71" class="reference"><a href="#cite_note-71"><span class="cite-bracket">[</span>70<span class="cite-bracket">]</span></a></sup> </p><p>In June 1911, Van den Broek noted that on the <a href="/wiki/Periodic_table" title="Periodic table">periodic table</a>, each successive chemical element increased in atomic weight on average by 2, which in turn suggested that each successive element's nuclear charge increased by 1 <i>q</i><sub>e</sub>.<sup id="cite_ref-72" class="reference"><a href="#cite_note-72"><span class="cite-bracket">[</span>71<span class="cite-bracket">]</span></a></sup> In 1913, van den Broek further proposed that the electric charge of an atom's nucleus, expressed as a multiplier of the <a href="/wiki/Elementary_charge" title="Elementary charge">elementary charge</a>, is equal to the element's sequential position on the periodic table. Rutherford defined this position as being the element's <a href="/wiki/Atomic_number" title="Atomic number">atomic number</a>.<sup id="cite_ref-73" class="reference"><a href="#cite_note-73"><span class="cite-bracket">[</span>72<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-74" class="reference"><a href="#cite_note-74"><span class="cite-bracket">[</span>73<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-75" class="reference"><a href="#cite_note-75"><span class="cite-bracket">[</span>74<span class="cite-bracket">]</span></a></sup> </p><p>In 1913, <a href="/wiki/Henry_Moseley" title="Henry Moseley">Henry Moseley</a> measured the X-ray emissions of all the elements on the periodic table and found that the frequency of the X-ray emissions was a mathematical function of the element's atomic number and the charge of a hydrogen nucleus <style data-mw-deduplicate="TemplateStyles:r1033199720">.mw-parser-output div.crossreference{padding-left:0}</style><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><span role="note" class="hatnote navigation-not-searchable crossreference">(see <a href="/wiki/Moseley%27s_law" title="Moseley's law">Moseley's law</a>)</span>.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (October 2024)">citation needed</span></a></i>]</sup> </p><p>In 1917 <a href="/wiki/Ernest_Rutherford" title="Ernest Rutherford">Rutherford</a> bombarded <a href="/wiki/Nitrogen" title="Nitrogen">nitrogen</a> gas with <a href="/wiki/Alpha_particle" title="Alpha particle">alpha particles</a> and observed <a href="/wiki/Hydrogen" title="Hydrogen">hydrogen</a> ions being emitted from the gas. Rutherford concluded that the alpha particles struck the nuclei of the nitrogen atoms, causing hydrogen ions to split off.<sup id="cite_ref-76" class="reference"><a href="#cite_note-76"><span class="cite-bracket">[</span>75<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-77" class="reference"><a href="#cite_note-77"><span class="cite-bracket">[</span>76<span class="cite-bracket">]</span></a></sup> </p><p>These observations led Rutherford to conclude that the hydrogen nucleus was a singular particle with a positive charge equal to that of the electron's negative charge. The name "proton" was suggested by Rutherford at an informal meeting of fellow physicists in Cardiff in 1920.<sup id="cite_ref-78" class="reference"><a href="#cite_note-78"><span class="cite-bracket">[</span>77<span class="cite-bracket">]</span></a></sup> </p><p>The charge number of an atomic nucleus was found to be equal to the element's ordinal position on the periodic table. The nuclear charge number thus provided a simple and clear-cut way of distinguishing the <a href="/wiki/Chemical_element" title="Chemical element">chemical elements</a> from each other, as opposed to <a href="/wiki/Antoine_Lavoisier" title="Antoine Lavoisier">Lavoisier's</a> classic definition of a chemical element being a substance that cannot be broken down into simpler substances by chemical reactions. The charge number or proton number was thereafter referred to as the <a href="/wiki/Atomic_number" title="Atomic number">atomic number</a> of the element. In 1923, the International Committee on Chemical Elements officially declared the atomic number to be the distinguishing quality of a chemical element.<sup id="cite_ref-79" class="reference"><a href="#cite_note-79"><span class="cite-bracket">[</span>78<span class="cite-bracket">]</span></a></sup> </p><p>During the 1920s, some writers defined the atomic number as being the number of "excess protons" in a nucleus. Before the discovery of the <a href="/wiki/Neutron" title="Neutron">neutron</a>, scientists believed that the atomic nucleus contained a number of "nuclear electrons" which cancelled out the positive charge of some of its protons. This explained why the atomic weights of most atoms were higher than their atomic numbers. Helium, for instance, was thought to have four protons and two nuclear electrons in the nucleus, leaving two excess protons and a net nuclear charge of 2+. After the neutron was discovered, scientists realized the helium nucleus in fact contained two protons and two neutrons. </p> <div class="mw-heading mw-heading2"><h2 id="Discovery_of_the_neutron">Discovery of the neutron</h2></div> <p>Physicists in the 1920s believed that the atomic nucleus contained protons plus a number of "nuclear electrons" that reduced the overall charge. These "nuclear electrons" were distinct from the electrons that orbited the nucleus. This incorrect hypothesis would have explained why the atomic numbers of the elements were less than their atomic weights, and why radioactive elements emit electrons (<a href="/wiki/Beta_radiation" class="mw-redirect" title="Beta radiation">beta radiation</a>) in the process of nuclear decay. Rutherford even hypothesized that a proton and an electron could bind tightly together into a "neutral doublet". Rutherford wrote that the existence of such "neutral doublets" moving freely through space would provide a more plausible explanation for how the heavier elements could have formed in the genesis of the Universe, given that it is hard for a lone proton to fuse with a large atomic nucleus because of the repulsive electric field.<sup id="cite_ref-80" class="reference"><a href="#cite_note-80"><span class="cite-bracket">[</span>79<span class="cite-bracket">]</span></a></sup> </p><p>In 1928, <a href="/wiki/Walter_Bothe" class="mw-redirect" title="Walter Bothe">Walter Bothe</a> observed that <a href="/wiki/Beryllium" title="Beryllium">beryllium</a> emitted a highly penetrating, electrically neutral radiation when bombarded with alpha particles. It was later discovered that this radiation could knock hydrogen atoms out of <a href="/wiki/Paraffin_wax" title="Paraffin wax">paraffin wax</a>. Initially it was thought to be high-energy <a href="/wiki/Gamma_radiation" class="mw-redirect" title="Gamma radiation">gamma radiation</a>, since gamma radiation had a similar effect on electrons in metals, but <a href="/wiki/James_Chadwick" title="James Chadwick">James Chadwick</a> found that the <a href="/wiki/Ionization" title="Ionization">ionization</a> effect was too strong for it to be due to electromagnetic radiation, so long as energy and momentum were conserved in the interaction. In 1932, Chadwick exposed various elements, such as hydrogen and nitrogen, to the mysterious "beryllium radiation", and by measuring the energies of the recoiling charged particles, he deduced that the radiation was actually composed of electrically neutral particles which could not be massless like the gamma ray, but instead were required to have a mass similar to that of a proton. Chadwick called this new particle "the neutron" and believed that it to be a proton and electron fused together because the neutron had about the same mass as a proton and an electron's mass is negligible by comparison.<sup id="cite_ref-81" class="reference"><a href="#cite_note-81"><span class="cite-bracket">[</span>80<span class="cite-bracket">]</span></a></sup> Neutrons are not in fact a fusion of a proton and an electron. </p> <div class="mw-heading mw-heading2"><h2 id="Modern_quantum_mechanical_models">Modern quantum mechanical models</h2></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/History_of_quantum_mechanics" title="History of quantum mechanics">History of quantum mechanics</a></div> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:S-p-Orbitals.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/0/0f/S-p-Orbitals.svg/220px-S-p-Orbitals.svg.png" decoding="async" width="220" height="73" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/0f/S-p-Orbitals.svg/330px-S-p-Orbitals.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/0f/S-p-Orbitals.svg/440px-S-p-Orbitals.svg.png 2x" data-file-width="1813" data-file-height="600" /></a><figcaption>The five filled atomic orbitals of a neon atom separated and arranged in order of increasing energy from left to right, with the last three orbitals being <a href="/wiki/Degenerate_energy_levels" title="Degenerate energy levels">equal in energy</a>. Each orbital holds up to two electrons, which most probably exist in the zones represented by the colored bubbles. Each electron is equally present in both orbital zones, shown here by color only to highlight the different wave phase.</figcaption></figure> <p>In 1924, <a href="/wiki/Louis_de_Broglie" title="Louis de Broglie">Louis de Broglie</a> proposed that all particles—particularly subatomic particles such as electrons—have an associated wave. <a href="/wiki/Erwin_Schr%C3%B6dinger" title="Erwin Schrödinger">Erwin Schrödinger</a>, fascinated by this idea, developed an equation<sup id="cite_ref-schrodinger_82-0" class="reference"><a href="#cite_note-schrodinger-82"><span class="cite-bracket">[</span>81<span class="cite-bracket">]</span></a></sup> that describes an electron as a <a href="/wiki/Wave_function" title="Wave function">wave function</a> instead of a point. This approach predicted many of the spectral phenomena that Bohr's model failed to explain, but it was difficult to visualize, and faced opposition.<sup id="cite_ref-Mahanti_83-0" class="reference"><a href="#cite_note-Mahanti-83"><span class="cite-bracket">[</span>82<span class="cite-bracket">]</span></a></sup> One of its critics, <a href="/wiki/Max_Born" title="Max Born">Max Born</a>, proposed instead that Schrödinger's wave function did not describe the physical extent of an electron (like a charge distribution in classical electromagnetism), but rather gave the probability that an electron would, when measured, be found at a particular point.<sup id="cite_ref-84" class="reference"><a href="#cite_note-84"><span class="cite-bracket">[</span>83<span class="cite-bracket">]</span></a></sup> This reconciled the ideas of wave-like and particle-like electrons: the behavior of an electron, or of any other subatomic entity, has <a href="/wiki/Wave%E2%80%93particle_duality" title="Wave–particle duality">both wave-like and particle-like aspects</a>, and whether one aspect or the other is observed depend upon the experiment.<sup id="cite_ref-85" class="reference"><a href="#cite_note-85"><span class="cite-bracket">[</span>84<span class="cite-bracket">]</span></a></sup> </p><p>A consequence of describing particles as waveforms rather than points is that it is mathematically impossible to calculate with precision both the position and momentum of a particle at a given point in time. This became known as the <a href="/wiki/Uncertainty_principle" title="Uncertainty principle">uncertainty principle</a>, a concept first introduced by <a href="/wiki/Werner_Heisenberg" title="Werner Heisenberg">Werner Heisenberg</a> in 1927.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (October 2024)">citation needed</span></a></i>]</sup> </p><p>Schrödinger's wave model for hydrogen replaced Bohr's model, with its neat, clearly defined circular orbits. The <a href="/wiki/Atomic_orbital" title="Atomic orbital">modern model of the atom</a> describes the positions of electrons in an atom in terms of probabilities. An electron can potentially be found at any distance from the nucleus, but, depending on its energy level and <a href="/wiki/Angular_momentum" title="Angular momentum">angular momentum</a>, exists more frequently in certain regions around the nucleus than others; this pattern is referred to as its <a href="/wiki/Atomic_orbital" title="Atomic orbital">atomic orbital</a>. The orbitals come in a variety of shapes—<a href="/wiki/Sphere" title="Sphere">sphere</a>, <a href="/wiki/Dumbbell" title="Dumbbell">dumbbell</a>, <a href="/wiki/Torus" title="Torus">torus</a>, etc.—with the nucleus in the middle.<sup id="cite_ref-86" class="reference"><a href="#cite_note-86"><span class="cite-bracket">[</span>85<span class="cite-bracket">]</span></a></sup> The shapes of atomic orbitals are found by solving the Schrödinger equation.<sup id="cite_ref-87" class="reference"><a href="#cite_note-87"><span class="cite-bracket">[</span>86<span class="cite-bracket">]</span></a></sup> Analytic solutions of the Schrödinger equation are known for <a href="/wiki/List_of_quantum-mechanical_systems_with_analytical_solutions" title="List of quantum-mechanical systems with analytical solutions">very few relatively simple model Hamiltonians</a> including the <a href="/wiki/Hydrogen_atom" title="Hydrogen atom">hydrogen atom</a> and the <a href="/wiki/Dihydrogen_cation" title="Dihydrogen cation">hydrogen molecular ion</a>.<sup id="cite_ref-88" class="reference"><a href="#cite_note-88"><span class="cite-bracket">[</span>87<span class="cite-bracket">]</span></a></sup> Beginning with the <a href="/wiki/Helium" title="Helium">helium</a> atom—which contains just two electrons—numerical methods are used to solve the Schrödinger equation.<sup id="cite_ref-89" class="reference"><a href="#cite_note-89"><span class="cite-bracket">[</span>88<span class="cite-bracket">]</span></a></sup> </p><p>Qualitatively the shape of the atomic orbitals of multi-electron atoms resemble the states of the hydrogen atom. The <a href="/wiki/Pauli_principle" class="mw-redirect" title="Pauli principle">Pauli principle</a> requires the distribution of these electrons within the atomic orbitals such that no more than two electrons are assigned to any one orbital; this requirement profoundly affects the atomic properties and ultimately the bonding of atoms into molecules.<sup id="cite_ref-90" class="reference"><a href="#cite_note-90"><span class="cite-bracket">[</span>89<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 182">: 182 </span></sup> </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2></div> <style data-mw-deduplicate="TemplateStyles:r1239009302">.mw-parser-output .portalbox{padding:0;margin:0.5em 0;display:table;box-sizing:border-box;max-width:175px;list-style:none}.mw-parser-output .portalborder{border:1px solid var(--border-color-base,#a2a9b1);padding:0.1em;background:var(--background-color-neutral-subtle,#f8f9fa)}.mw-parser-output .portalbox-entry{display:table-row;font-size:85%;line-height:110%;height:1.9em;font-style:italic;font-weight:bold}.mw-parser-output .portalbox-image{display:table-cell;padding:0.2em;vertical-align:middle;text-align:center}.mw-parser-output .portalbox-link{display:table-cell;padding:0.2em 0.2em 0.2em 0.3em;vertical-align:middle}@media(min-width:720px){.mw-parser-output .portalleft{clear:left;float:left;margin:0.5em 1em 0.5em 0}.mw-parser-output .portalright{clear:right;float:right;margin:0.5em 0 0.5em 1em}}</style><ul role="navigation" aria-label="Portals" class="noprint portalbox portalborder portalright"> <li class="portalbox-entry"><span class="portalbox-image"><span class="noviewer" typeof="mw:File"><a href="/wiki/File:Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg" class="mw-file-description"><img alt="icon" src="//upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/25px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png" decoding="async" width="25" height="28" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/37px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/49px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png 2x" data-file-width="530" data-file-height="600" /></a></span></span><span class="portalbox-link"><a href="/wiki/Portal:Physics" title="Portal:Physics">Physics portal</a></span></li></ul> <style data-mw-deduplicate="TemplateStyles:r1184024115">.mw-parser-output .div-col{margin-top:0.3em;column-width:30em}.mw-parser-output .div-col-small{font-size:90%}.mw-parser-output .div-col-rules{column-rule:1px solid #aaa}.mw-parser-output .div-col dl,.mw-parser-output .div-col ol,.mw-parser-output .div-col ul{margin-top:0}.mw-parser-output .div-col li,.mw-parser-output .div-col dd{page-break-inside:avoid;break-inside:avoid-column}</style><div class="div-col"> <ul><li><a href="/wiki/Spectroscopy" title="Spectroscopy">Spectroscopy</a></li> <li><a href="/wiki/Atom" title="Atom">Atom</a></li> <li><a href="/wiki/History_of_molecular_theory" title="History of molecular theory">History of molecular theory</a></li> <li><a href="/wiki/Timeline_of_chemical_element_discoveries" class="mw-redirect" title="Timeline of chemical element discoveries">Timeline of chemical element discoveries</a></li> <li><a href="/wiki/Introduction_to_quantum_mechanics" title="Introduction to quantum mechanics">Introduction to quantum mechanics</a></li> <li><a href="/wiki/Kinetic_theory_of_gases" title="Kinetic theory of gases">Kinetic theory of gases</a></li> <li><a href="/wiki/Atomism" title="Atomism">Atomism</a></li> <li><i><a href="/wiki/The_Physical_Principles_of_the_Quantum_Theory" title="The Physical Principles of the Quantum Theory">The Physical Principles of the Quantum Theory</a></i></li></ul> </div> <div class="mw-heading mw-heading2"><h2 id="Footnotes">Footnotes</h2></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist reflist-lower-alpha"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text">a combination of the negative term "a-" and "τομή," the term for "cut"</span> </li> </ol></div></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239543626"><div class="reflist reflist-columns references-column-width" style="column-width: 30em;"> <ol class="references"> <li id="cite_note-feynmanleightonsands1963-atomic-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-feynmanleightonsands1963-atomic_1-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFFeynmanLeightonSands1963">Feynman, Leighton & Sands 1963</a>, p. I-2 "If, in some cataclysm, all [] scientific knowledge were to be destroyed [save] one sentence [...] what statement would contain the most information in the fewest words? I believe it is [...] that <i>all things are made up of atoms – little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another</i> ..."</span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFPullman1998" class="citation book cs1">Pullman, Bernard (1998). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=IQs5hur-BpgC&q=Leucippus+Democritus+atom&pg=PA56"><i>The Atom in the History of Human Thought</i></a>. Oxford, England: Oxford University Press. pp. 31–33. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-19-515040-7" title="Special:BookSources/978-0-19-515040-7"><bdi>978-0-19-515040-7</bdi></a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20210205165029/https://books.google.com/books?id=IQs5hur-BpgC&q=Leucippus+Democritus+atom&pg=PA56">Archived</a> from the original on 5 February 2021<span class="reference-accessdate">. Retrieved <span class="nowrap">25 October</span> 2020</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Atom+in+the+History+of+Human+Thought&rft.place=Oxford%2C+England&rft.pages=31-33&rft.pub=Oxford+University+Press&rft.date=1998&rft.isbn=978-0-19-515040-7&rft.aulast=Pullman&rft.aufirst=Bernard&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DIQs5hur-BpgC%26q%3DLeucippus%2BDemocritus%2Batom%26pg%3DPA56&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><a href="#refMelsen1952">Melsen (1952). <i>From Atomos to Atom</i>, pp. 18–19</a></span> </li> <li id="cite_note-Pullman_1998_p._201-5"><span class="mw-cite-backlink">^ <a href="#cite_ref-Pullman_1998_p._201_5-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Pullman_1998_p._201_5-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-Pullman_1998_p._201_5-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><a href="#refPullman1998">Pullman (1998). <i>The Atom in the History of Human Thought</i>, p. 201</a></span> </li> <li id="cite_note-Whittaker-6"><span class="mw-cite-backlink">^ <a href="#cite_ref-Whittaker_6-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Whittaker_6-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-Whittaker_6-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-Whittaker_6-3"><sup><i><b>d</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWhittaker1989" class="citation book cs1">Whittaker, Edmund T. (1989). <i>A history of the theories of aether & electricity. 1: The classical theories</i> (Repr ed.). New York: Dover Publ. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-486-26126-3" title="Special:BookSources/978-0-486-26126-3"><bdi>978-0-486-26126-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=A+history+of+the+theories+of+aether+%26+electricity.+1%3A+The+classical+theories&rft.place=New+York&rft.edition=Repr&rft.pub=Dover+Publ&rft.date=1989&rft.isbn=978-0-486-26126-3&rft.aulast=Whittaker&rft.aufirst=Edmund+T.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text">Pullman (1998). <i>The Atom in the History of Human Thought</i>. p. 197</span> </li> <li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.britannica.com/science/law-of-definite-proportions">"Law of definite proportions | chemistry"</a>. <i>Encyclopedia Britannica</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2020-09-03</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Encyclopedia+Britannica&rft.atitle=Law+of+definite+proportions+%7C+chemistry&rft_id=https%3A%2F%2Fwww.britannica.com%2Fscience%2Flaw-of-definite-proportions&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text">Pullman (1998). <i>The Atom in the History of Human Thought</i>, p. 199: "The constant ratios, expressible in terms of integers, of the weights of the constituents in composite bodies could be construed as evidence on a macroscopic scale of interactions at the microscopic level between basic units with fixed weights. For Dalton, this agreement strongly suggested a corpuscular structure of matter, even though it did not constitute definite proof."</span> </li> <li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text">Thomas Thomson (1831). <i>A History of Chemistry, Volume 2</i>. p. 291</span> </li> <li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><a href="#refDalton1817">Dalton (1817). <i>A New System of Chemical Philosophy</i> vol. 2, p. 36</a></span> </li> <li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"><a href="#refMelsen1952">Melsen (1952). <i>From Atomos to Atom</i>. p. 137</a></span> </li> <li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text"><i>Hawley's Condensed Chemical Dictionary</i> 16th edition, p. 1270</span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text">William Rossiter (1879). <i>An Illustrated Dictionary of Scientific Terms</i>, p. 98</span> </li> <li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text">Dalton (1817). <i>A New System of Chemical Philosophy</i> vol. 2. pp. 28-34: "the intermediate or red oxide is 2 atoms protoxide and 1 of oxygen"</span> </li> <li id="cite_note-16"><span class="mw-cite-backlink"><b><a href="#cite_ref-16">^</a></b></span> <span class="reference-text"><a href="#refMillington1906">Millington (1906). <i>John Dalton</i>, p. 113</a></span> </li> <li id="cite_note-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-17">^</a></b></span> <span class="reference-text"><a href="#refDalton1808">Dalton (1808). <i>A New System of Chemical Philosophy</i> vol. 1, pp. 316–319</a></span> </li> <li id="cite_note-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-18">^</a></b></span> <span class="reference-text"><a href="#refDalton1808">Dalton (1808). <i>A New System of Chemical Philosophy</i> vol. 1. pp. 316–319</a></span> </li> <li id="cite_note-19"><span class="mw-cite-backlink"><b><a href="#cite_ref-19">^</a></b></span> <span class="reference-text"><a href="#refHolbrowEtAl2010">Holbrow et al. (2010). <i>Modern Introductory Physics</i>, pp. 65–66</a></span> </li> <li id="cite_note-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-20">^</a></b></span> <span class="reference-text">Dalton, quoted in Freund (1904). <i>The Study of Chemical Composition</i>. p. 288: "I have chosen the word atom to signify these ultimate particles in preference to particle, molecule, or any other diminiutive term, because I conceive it is much more expressive; it includes in itself the notion of indivisible, which the other terms do not. It may, perhaps, be said that I extend the application of it too far when I speak of compound atoms; for instance, I call an ultimate particle of carbonic acid a compound atom. Now, though this atom may be divided, yet it ceases to become carbonic acid, being resolved by such division into charcoal and oxygen. Hence I conceive there is no inconsistency in speaking of compound atoms and that my meaning cannot be misunderstood."</span> </li> <li id="cite_note-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-21">^</a></b></span> <span class="reference-text"><a href="#refDalton1817">Dalton (1817). <i>A New System of Chemical Philosophy</i> vol. 1, pp. 213–214</a></span> </li> <li id="cite_note-avogadro-22"><span class="mw-cite-backlink"><b><a href="#cite_ref-avogadro_22-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAvogadro,_Amedeo1811" class="citation journal cs1">Avogadro, Amedeo (1811). <a rel="nofollow" class="external text" href="http://web.lemoyne.edu/~giunta/avogadro.html">"Essay on a Manner of Determining the Relative Masses of the Elementary Molecules of Bodies, and the Proportions in Which They Enter into These Compounds"</a>. <i>Journal de Physique</i>. <b>73</b>: 58–76.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+de+Physique&rft.atitle=Essay+on+a+Manner+of+Determining+the+Relative+Masses+of+the+Elementary+Molecules+of+Bodies%2C+and+the+Proportions+in+Which+They+Enter+into+These+Compounds&rft.volume=73&rft.pages=58-76&rft.date=1811&rft.au=Avogadro%2C+Amedeo&rft_id=http%3A%2F%2Fweb.lemoyne.edu%2F~giunta%2Favogadro.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-23"><span class="mw-cite-backlink"><b><a href="#cite_ref-23">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAvogadro1811" class="citation journal cs1"><a href="/wiki/Amedeo_Avogadro" title="Amedeo Avogadro">Avogadro, Amedeo</a> (1811). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=MxgTAAAAQAAJ&pg=PA58">"Essai d'une manière de déterminer les masses relatives des molécules élémentaires des corps, et les proportions selon lesquelles elles entrent dans ces combinaisons"</a>. <i>Journal de Physique</i>. <b>73</b>: 58–76.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+de+Physique&rft.atitle=Essai+d%27une+mani%C3%A8re+de+d%C3%A9terminer+les+masses+relatives+des+mol%C3%A9cules+%C3%A9l%C3%A9mentaires+des+corps%2C+et+les+proportions+selon+lesquelles+elles+entrent+dans+ces+combinaisons&rft.volume=73&rft.pages=58-76&rft.date=1811&rft.aulast=Avogadro&rft.aufirst=Amedeo&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DMxgTAAAAQAAJ%26pg%3DPA58&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span> <a rel="nofollow" class="external text" href="http://web.lemoyne.edu/~giunta/avogadro.html">English translation</a></span> </li> <li id="cite_note-24"><span class="mw-cite-backlink"><b><a href="#cite_ref-24">^</a></b></span> <span class="reference-text"><a href="#refTrusted1999">Trusted (1999). <i>The Mystery of Matter</i>, p. 73</a></span> </li> <li id="cite_note-25"><span class="mw-cite-backlink"><b><a href="#cite_ref-25">^</a></b></span> <span class="reference-text">Pullman (1998). <i>The Atom in the History of Human Thought</i>, p. 199: "The constant ratios, expressible in terms of integers, of the weights of the constituents in composite bodies could be construed as evidence on a macroscopic scale of interactions at the microscopic level between basic units with fixed weights. For Dalton, this agreement strongly suggested a corpuscular structure of matter, even though it did not constitute definite proof."</span> </li> <li id="cite_note-26"><span class="mw-cite-backlink"><b><a href="#cite_ref-26">^</a></b></span> <span class="reference-text">Freund (1904). <i>The Study of Chemical Composition</i>. p. 288</span> </li> <li id="cite_note-27"><span class="mw-cite-backlink"><b><a href="#cite_ref-27">^</a></b></span> <span class="reference-text"><a href="#refPullman1998">Pullman (1998). <i>The Atom in the History of Human Thought</i>, p. 202</a></span> </li> <li id="cite_note-28"><span class="mw-cite-backlink"><b><a href="#cite_ref-28">^</a></b></span> <span class="reference-text">Jean-Baptiste Dumas (1836). <i>Leçons sur la philosophie chimique</i> [<i>Lessons on Chemical Philosophy</i>]. 285–287</span> </li> <li id="cite_note-29"><span class="mw-cite-backlink"><b><a href="#cite_ref-29">^</a></b></span> <span class="reference-text">Pullman (1998). <i>The Atom in the History of Human Thought</i>. p. 207</span> </li> <li id="cite_note-30"><span class="mw-cite-backlink"><b><a href="#cite_ref-30">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://archive.org/details/sketchofcourseof00cannrich/page/2/mode/2up">Cannizzaro (1858). <i>Sketch of a Course of Chemical Philosophy</i>. pp. 2–4</a></span> </li> <li id="cite_note-31"><span class="mw-cite-backlink"><b><a href="#cite_ref-31">^</a></b></span> <span class="reference-text"><a href="#refPullman1998">Pullman (1998). <i>The Atom in the History of Human Thought</i>, p. 226</a>: "The first development is the establishment of the periodic classification of the elements, marking the successful climax of concerted efforts to arrange the chemical properties of elements according to their atomic weight. The second is the emergence of structural chemistry, which ousted what was a simple and primitive verbal description of the elemental composition, be it atomic or equivalentist, of substances and replaced it with a systematic determination of their internal architecture."</span> </li> <li id="cite_note-32"><span class="mw-cite-backlink"><b><a href="#cite_ref-32">^</a></b></span> <span class="reference-text"><a href="#refPullman1998">Pullman (1998). <i>The Atom in the History of Human Thought</i>, p. 230</a></span> </li> <li id="cite_note-33"><span class="mw-cite-backlink"><b><a href="#cite_ref-33">^</a></b></span> <span class="reference-text"><a href="#refMelsen1952">Melsen (1952). <i>From Atomos to Atom</i>, pp. 147–148</a></span> </li> <li id="cite_note-34"><span class="mw-cite-backlink"><b><a href="#cite_ref-34">^</a></b></span> <span class="reference-text">Henry Enfield Roscoe, Carl Schorlemmer (1895). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=JU1KAAAAYAAJ&pg=PA121"><i>A Treatise on Chemistry</i>, Volume 3, Part 1, pp. 121–122</a></span> </li> <li id="cite_note-35"><span class="mw-cite-backlink"><b><a href="#cite_ref-35">^</a></b></span> <span class="reference-text">Henry Enfield Roscoe, Carl Schorlemmer (1895). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=JU1KAAAAYAAJ&pg=PA121"><i>A Treatise on Chemistry</i>, Volume 3, Part 1, pp. 121</a>: "The radical theory and the theory of types are capable of explaining many cases of isomerism, but it was not until the doctrine of the linking of atoms was established that a clear light was thrown on this subject."</span> </li> <li id="cite_note-36"><span class="mw-cite-backlink"><b><a href="#cite_ref-36">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://books.google.com/books?id=vTY6AAAAMAAJ&pg=PA291">Adolphe Wurtz (1880). <i>The Atomic Theory</i>, p. 291</a>: "It is in this manner that the theory of atomicity predicts, interprets, and limits the number of isomers; it has furnished the elements of one of the greatest advances which science has accomplished in the last twenty years. [...] The theory of atomicity has successfully attacked the problem by introducing into the discussion exact data, which have been in a great number of cases confirmed by experiment."</span> </li> <li id="cite_note-Scerri-37"><span class="mw-cite-backlink">^ <a href="#cite_ref-Scerri_37-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Scerri_37-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFScerri2020" class="citation book cs1"><a href="/wiki/Eric_Scerri" title="Eric Scerri">Scerri, Eric R.</a> (2020). <i>The Periodic Table, Its Story and Its Significance</i> (2nd ed.). New York: Oxford University Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-190-91436-3" title="Special:BookSources/978-0-190-91436-3"><bdi>978-0-190-91436-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Periodic+Table%2C+Its+Story+and+Its+Significance&rft.place=New+York&rft.edition=2nd&rft.pub=Oxford+University+Press&rft.date=2020&rft.isbn=978-0-190-91436-3&rft.aulast=Scerri&rft.aufirst=Eric+R.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-38"><span class="mw-cite-backlink"><b><a href="#cite_ref-38">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBritoRodríguezNiaz2005" class="citation journal cs1">Brito, Angmary; Rodríguez, María A.; Niaz, Mansoor (2005). "A Reconstruction of Development of the Periodic Table Based on History and Philosophy of Science and Its Implications for General Chemistry Textbooks". <i>Journal of Research in Science Teaching</i>. <b>42</b> (1): 84–111. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2005JRScT..42...84B">2005JRScT..42...84B</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Ftea.20044">10.1002/tea.20044</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Research+in+Science+Teaching&rft.atitle=A+Reconstruction+of+Development+of+the+Periodic+Table+Based+on+History+and+Philosophy+of+Science+and+Its+Implications+for+General+Chemistry+Textbooks&rft.volume=42&rft.issue=1&rft.pages=84-111&rft.date=2005&rft_id=info%3Adoi%2F10.1002%2Ftea.20044&rft_id=info%3Abibcode%2F2005JRScT..42...84B&rft.aulast=Brito&rft.aufirst=Angmary&rft.au=Rodr%C3%ADguez%2C+Mar%C3%ADa+A.&rft.au=Niaz%2C+Mansoor&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-39"><span class="mw-cite-backlink"><b><a href="#cite_ref-39">^</a></b></span> <span class="reference-text">See: <ul><li>Maxwell, J.C. (1860) <a rel="nofollow" class="external text" href="https://books.google.com/books?id=-YU7AQAAMAAJ&pg=PA19">"Illustrations of the dynamical theory of gases. Part I. On the motions and collisions of perfectly elastic spheres,"</a> <i>Philosophical Magazine</i>, 4th series, <b>19</b> : 19–32.</li> <li>Maxwell, J.C. (1860) <a rel="nofollow" class="external text" href="https://books.google.com/books?id=DIc7AQAAMAAJ&pg=PA21">"Illustrations of the dynamical theory of gases. Part II. On the process of diffusion of two or more kinds of moving particles among one another,"</a> <i>Philosophical Magazine</i>, 4th series, <b>20</b> : 21–37.</li></ul> </span></li> <li id="cite_note-40"><span class="mw-cite-backlink"><b><a href="#cite_ref-40">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDeltete1999" class="citation journal cs1">Deltete, Robert (1999-04-01). <a rel="nofollow" class="external text" href="https://link.springer.com/article/10.1023/A:1005287003138">"Helm and Boltzmann: Energetics at the Lübeck Naturforscherversammlung"</a>. <i>Synthese</i>. <b>119</b> (1): 45–68. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1023%2FA%3A1005287003138">10.1023/A:1005287003138</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/1573-0964">1573-0964</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Synthese&rft.atitle=Helm+and+Boltzmann%3A+Energetics+at+the+L%C3%BCbeck+Naturforscherversammlung&rft.volume=119&rft.issue=1&rft.pages=45-68&rft.date=1999-04-01&rft_id=info%3Adoi%2F10.1023%2FA%3A1005287003138&rft.issn=1573-0964&rft.aulast=Deltete&rft.aufirst=Robert&rft_id=https%3A%2F%2Flink.springer.com%2Farticle%2F10.1023%2FA%3A1005287003138&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-41"><span class="mw-cite-backlink"><b><a href="#cite_ref-41">^</a></b></span> <span class="reference-text">Navarro, Luis. "Gibbs, Einstein and the Foundations of Statistical Mechanics." Archive for History of Exact Sciences, vol. 53, no. 2, Springer, 1998, pp. 147–80, <a rel="nofollow" class="external free" href="http://www.jstor.org/stable/41134058">http://www.jstor.org/stable/41134058</a>.</span> </li> <li id="cite_note-42"><span class="mw-cite-backlink"><b><a href="#cite_ref-42">^</a></b></span> <span class="reference-text">Stone, A. Douglas, Einstein and the quantum : the quest of the valiant Swabian, Princeton University Press, (2013). <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-691-13968-5" title="Special:BookSources/978-0-691-13968-5">978-0-691-13968-5</a> quoted from Folsing, Albert Einstein, 110.</span> </li> <li id="cite_note-43"><span class="mw-cite-backlink"><b><a href="#cite_ref-43">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.nobelprize.org/prizes/physics/1926/perrin/lecture/">"The Nobel Prize in Physics 1926"</a>. <i>NobelPrize.org</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2023-02-08</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=NobelPrize.org&rft.atitle=The+Nobel+Prize+in+Physics+1926&rft_id=https%3A%2F%2Fwww.nobelprize.org%2Fprizes%2Fphysics%2F1926%2Fperrin%2Flecture%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-44"><span class="mw-cite-backlink"><b><a href="#cite_ref-44">^</a></b></span> <span class="reference-text"><a href="#refPerrin1909">Perrin (1909). <i>Brownian Movement and Molecular Reality</i>, p. 50</a></span> </li> <li id="cite_note-45"><span class="mw-cite-backlink"><b><a href="#cite_ref-45">^</a></b></span> <span class="reference-text"><a href="#refPerrin1909">Perrin (1909). <i>Brownian Movement and Molecular Reality</i>, p. 50</a></span> </li> <li id="cite_note-PaisInwardBound-46"><span class="mw-cite-backlink">^ <a href="#cite_ref-PaisInwardBound_46-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-PaisInwardBound_46-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-PaisInwardBound_46-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPais2002" class="citation book cs1">Pais, Abraham (2002). <i>Inward bound: of matter and forces in the physical world</i> (Reprint ed.). Oxford: Clarendon Press [u.a.] <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-19-851997-3" title="Special:BookSources/978-0-19-851997-3"><bdi>978-0-19-851997-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Inward+bound%3A+of+matter+and+forces+in+the+physical+world&rft.place=Oxford&rft.edition=Reprint&rft.pub=Clarendon+Press+%5Bu.a.%5D&rft.date=2002&rft.isbn=978-0-19-851997-3&rft.aulast=Pais&rft.aufirst=Abraham&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-thomson-47"><span class="mw-cite-backlink"><b><a href="#cite_ref-thomson_47-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJ._J._Thomson1897" class="citation journal cs1">J. J. Thomson (1897). <a rel="nofollow" class="external text" href="https://web.mit.edu/8.13/8.13c/references-fall/relativisticdynamics/thomson-cathode-rays-1897.pdf">"Cathode rays"</a> <span class="cs1-format">(PDF)</span>. <i>Philosophical Magazine</i>. <b>44</b> (269): 293–316. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1080%2F14786449708621070">10.1080/14786449708621070</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Philosophical+Magazine&rft.atitle=Cathode+rays&rft.volume=44&rft.issue=269&rft.pages=293-316&rft.date=1897&rft_id=info%3Adoi%2F10.1080%2F14786449708621070&rft.au=J.+J.+Thomson&rft_id=https%3A%2F%2Fweb.mit.edu%2F8.13%2F8.13c%2Freferences-fall%2Frelativisticdynamics%2Fthomson-cathode-rays-1897.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span><br />"From these determinations we see that the value of m/e is independent of the nature of the gas, and that its value 10<sup>-7</sup> is very small compared with the value 10<sup>-4</sup>, which is the smallest value of this quantity previously known, and which is the value for the hydrogen ion in electrolysis."</span> </li> <li id="cite_note-48"><span class="mw-cite-backlink"><b><a href="#cite_ref-48">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJ._J._Thomson1898" class="citation journal cs1">J. J. Thomson (1898). <a rel="nofollow" class="external text" href="https://archive.org/details/londonedinburgh5461898lon/page/528/mode/2up">"On the Charge of Electricity carried by the Ions produced by Röntgen Rays"</a>. <i>The London, Edinburgh and Dublin Philosophical Magazine and Journal of Science</i>. 5. <b>46</b> (283): 528–545.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+London%2C+Edinburgh+and+Dublin+Philosophical+Magazine+and+Journal+of+Science&rft.atitle=On+the+Charge+of+Electricity+carried+by+the+Ions+produced+by+R%C3%B6ntgen+Rays&rft.volume=46&rft.issue=283&rft.pages=528-545&rft.date=1898&rft.au=J.+J.+Thomson&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Flondonedinburgh5461898lon%2Fpage%2F528%2Fmode%2F2up&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-49"><span class="mw-cite-backlink"><b><a href="#cite_ref-49">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJ._J._Thomson1899" class="citation journal cs1">J. J. Thomson (1899). <a rel="nofollow" class="external text" href="https://www.chemteam.info/Chem-History/Thomson-1899.html">"On the Masses of the Ions in Gases at Low Pressures"</a>. <i>Philosophical Magazine</i>. 5. <b>48</b> (295): 547–567.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Philosophical+Magazine&rft.atitle=On+the+Masses+of+the+Ions+in+Gases+at+Low+Pressures.&rft.volume=48&rft.issue=295&rft.pages=547-567&rft.date=1899&rft.au=J.+J.+Thomson&rft_id=https%3A%2F%2Fwww.chemteam.info%2FChem-History%2FThomson-1899.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span><br />"...the magnitude of this negative charge is about 6 × 10<sup>-10</sup> electrostatic units, and is equal to the positive charge carried by the hydrogen atom in the electrolysis of solutions. [...] In gases at low pressures these units of negative electric charge are always associated with carriers of a definite mass. This mass is exceedingly small, being only about 1.4 × 10<sup>-3</sup> of that of the hydrogen ion, the smallest mass hitherto recognized as capable of a separate existence. The production of negative electrification thus involves the splitting up of an atom, as from a collection of atoms something is detached whose mass is less than that of a single atom."</span> </li> <li id="cite_note-50"><span class="mw-cite-backlink"><b><a href="#cite_ref-50">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFOlenickApostolGoodstein1986" class="citation book cs1">Olenick, Richard P.; Apostol, Tom M.; Goodstein, David L. (1986-12-26). <a href="/wiki/The_Mechanical_Universe" title="The Mechanical Universe"><i>Beyond the Mechanical Universe: From Electricity to Modern Physics</i></a>. Cambridge University Press. p. 435. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-521-30430-6" title="Special:BookSources/978-0-521-30430-6"><bdi>978-0-521-30430-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Beyond+the+Mechanical+Universe%3A+From+Electricity+to+Modern+Physics&rft.pages=435&rft.pub=Cambridge+University+Press&rft.date=1986-12-26&rft.isbn=978-0-521-30430-6&rft.aulast=Olenick&rft.aufirst=Richard+P.&rft.au=Apostol%2C+Tom+M.&rft.au=Goodstein%2C+David+L.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-51"><span class="mw-cite-backlink"><b><a href="#cite_ref-51">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJ._J._Thomson1904" class="citation journal cs1">J. J. Thomson (March 1904). <a rel="nofollow" class="external text" href="https://zenodo.org/record/1430726">"On the Structure of the Atom: an Investigation of the Stability and Periods of Oscillation of a number of Corpuscles arranged at equal intervals around the Circumference of a Circle; with Application of the Results to the Theory of Atomic Structure"</a>. <i><a href="/wiki/Philosophical_Magazine" title="Philosophical Magazine">Philosophical Magazine</a></i>. Sixth series. <b>7</b> (39): 237–265. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1080%2F14786440409463107">10.1080/14786440409463107</a>. <a rel="nofollow" class="external text" href="https://ghostarchive.org/archive/20221009/https://zenodo.org/record/1430726/files/article.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 2022-10-09.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Philosophical+Magazine&rft.atitle=On+the+Structure+of+the+Atom%3A+an+Investigation+of+the+Stability+and+Periods+of+Oscillation+of+a+number+of+Corpuscles+arranged+at+equal+intervals+around+the+Circumference+of+a+Circle%3B+with+Application+of+the+Results+to+the+Theory+of+Atomic+Structure&rft.volume=7&rft.issue=39&rft.pages=237-265&rft.date=1904-03&rft_id=info%3Adoi%2F10.1080%2F14786440409463107&rft.au=J.+J.+Thomson&rft_id=https%3A%2F%2Fzenodo.org%2Frecord%2F1430726&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-52"><span class="mw-cite-backlink"><b><a href="#cite_ref-52">^</a></b></span> <span class="reference-text">J. J. Thomson (1907). <i>The Corpuscular Theory of Matter</i>, p. 103: "In default of exact knowledge of the nature of the way in which positive electricity occurs in the atom, we shall consider a case in which the positive electricity is distributed in the way most amenable to mathematical calculation, i.e., when it occurs as a sphere of uniform density, throughout which the corpuscles are distributed."</span> </li> <li id="cite_note-53"><span class="mw-cite-backlink"><b><a href="#cite_ref-53">^</a></b></span> <span class="reference-text">J. J. Thomson (1907). <i>On the Corpuscular Theory of Matter</i>, p. 26: "The simplest interpretation of these results is that the positive ions are the atoms or groups of atoms of various elements from which one or more corpuscles have been removed. That, in fact, the corpuscles are the vehicles by which electricity is carried from one body to another, a positively electrified body different from the same body when unelectrified in having lost some of its corpuscles while the negative electrified body is one with more corpuscles than the unelectrified one."</span> </li> <li id="cite_note-54"><span class="mw-cite-backlink"><b><a href="#cite_ref-54">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGiora_HonBernard_R._Goldstein2013" class="citation journal cs1">Giora Hon; Bernard R. Goldstein (2013). <a rel="nofollow" class="external text" href="https://onlinelibrary.wiley.com/doi/10.1002/andp.201300732">"J. J. Thomson's plum-pudding atomic model: The making of a scientific myth"</a>. <i>Annalen der Physik</i>. <b>525</b> (8–9): A129–A133. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2013AnP...525A.129H">2013AnP...525A.129H</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Fandp.201300732">10.1002/andp.201300732</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Annalen+der+Physik&rft.atitle=J.+J.+Thomson%27s+plum-pudding+atomic+model%3A+The+making+of+a+scientific+myth&rft.volume=525&rft.issue=8%E2%80%939&rft.pages=A129-A133&rft.date=2013&rft_id=info%3Adoi%2F10.1002%2Fandp.201300732&rft_id=info%3Abibcode%2F2013AnP...525A.129H&rft.au=Giora+Hon&rft.au=Bernard+R.+Goldstein&rft_id=https%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1002%2Fandp.201300732&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-55"><span class="mw-cite-backlink"><b><a href="#cite_ref-55">^</a></b></span> <span class="reference-text">J. J. Thomson, in a letter to <a href="/wiki/Oliver_Lodge" title="Oliver Lodge">Oliver Lodge</a> dated 11 April 1904, quoted in Davis & Falconer (1997):<br /> "With regard to positive electrification I have been in the habit of using the crude analogy of a liquid with a certain amount of cohesion, enough to keep it from flying to bits under its own repulsion. I have however always tried to keep the physical conception of the positive electricity in the background because I have always had hopes (not yet realised) of being able to do without positive electrification as a separate entity and to replace it by some property of the corpuscles."<br /></span> </li> <li id="cite_note-Heilbron1968-56"><span class="mw-cite-backlink">^ <a href="#cite_ref-Heilbron1968_56-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Heilbron1968_56-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHeilbron1968" class="citation journal cs1">Heilbron, John L. (1968). <a rel="nofollow" class="external text" href="https://www.jstor.org/stable/41133273">"The Scattering of α and β Particles and Rutherford's Atom"</a>. <i>Archive for History of Exact Sciences</i>. <b>4</b> (4): 247–307. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2FBF00411591">10.1007/BF00411591</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0003-9519">0003-9519</a>. <a href="/wiki/JSTOR_(identifier)" class="mw-redirect" title="JSTOR (identifier)">JSTOR</a> <a rel="nofollow" class="external text" href="https://www.jstor.org/stable/41133273">41133273</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Archive+for+History+of+Exact+Sciences&rft.atitle=The+Scattering+of+%CE%B1+and+%CE%B2+Particles+and+Rutherford%27s+Atom&rft.volume=4&rft.issue=4&rft.pages=247-307&rft.date=1968&rft.issn=0003-9519&rft_id=https%3A%2F%2Fwww.jstor.org%2Fstable%2F41133273%23id-name%3DJSTOR&rft_id=info%3Adoi%2F10.1007%2FBF00411591&rft.aulast=Heilbron&rft.aufirst=John+L.&rft_id=https%3A%2F%2Fwww.jstor.org%2Fstable%2F41133273&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-Heilbron2003p64-68-57"><span class="mw-cite-backlink">^ <a href="#cite_ref-Heilbron2003p64-68_57-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Heilbron2003p64-68_57-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><a href="#refHeilbron2003">Heilbron (2003). <i>Ernest Rutherford and the Explosion of Atoms</i>, pp. 64–68</a></span> </li> <li id="cite_note-58"><span class="mw-cite-backlink"><b><a href="#cite_ref-58">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFEric_Scerri2017" class="citation journal cs1">Eric Scerri (6 March 2017). "The Gulf between chemistry and philosophy of chemistry, then and now". <i>Structural Chemistry</i>. <b>28</b>: 1599–1605. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2Fs11224-017-0948-5">10.1007/s11224-017-0948-5</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Structural+Chemistry&rft.atitle=The+Gulf+between+chemistry+and+philosophy+of+chemistry%2C+then+and+now&rft.volume=28&rft.pages=1599-1605&rft.date=2017-03-06&rft_id=info%3Adoi%2F10.1007%2Fs11224-017-0948-5&rft.au=Eric+Scerri&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-59"><span class="mw-cite-backlink"><b><a href="#cite_ref-59">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external free" href="https://archive.org/details/sim_nature-uk_1913-11-27_92_2300/page/372/mode/2up">https://archive.org/details/sim_nature-uk_1913-11-27_92_2300/page/372/mode/2up</a></span> </li> <li id="cite_note-60"><span class="mw-cite-backlink"><b><a href="#cite_ref-60">^</a></b></span> <span class="reference-text">J. W. Nicholson, Month. Not. Roy. Astr. Soc. lxxii. pp. 49,130, 677, 693, 729 (1912).</span> </li> <li id="cite_note-61"><span class="mw-cite-backlink"><b><a href="#cite_ref-61">^</a></b></span> <span class="reference-text">The Atomic Theory of John William Nicholson, Russell McCormmach, Archive for History of Exact Sciences, Vol. 3, No. 2 (25.8.1966), pp. 160–184 (25 pages), Springer.</span> </li> <li id="cite_note-NBohr-62"><span class="mw-cite-backlink">^ <a href="#cite_ref-NBohr_62-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-NBohr_62-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-NBohr_62-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBohr,_Niels1913" class="citation journal cs1">Bohr, Niels (1913). <a rel="nofollow" class="external text" href="http://www.ffn.ub.es/luisnavarro/nuevo_maletin/Bohr_1913.pdf">"On the constitution of atoms and molecules"</a> <span class="cs1-format">(PDF)</span>. <i>Philosophical Magazine</i>. <b>26</b> (153): 476–502. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1913PMag...26..476B">1913PMag...26..476B</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1080%2F14786441308634993">10.1080/14786441308634993</a>. <a rel="nofollow" class="external text" href="https://ghostarchive.org/archive/20221009/http://www.ffn.ub.es/luisnavarro/nuevo_maletin/Bohr_1913.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 2022-10-09.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Philosophical+Magazine&rft.atitle=On+the+constitution+of+atoms+and+molecules&rft.volume=26&rft.issue=153&rft.pages=476-502&rft.date=1913&rft_id=info%3Adoi%2F10.1080%2F14786441308634993&rft_id=info%3Abibcode%2F1913PMag...26..476B&rft.au=Bohr%2C+Niels&rft_id=http%3A%2F%2Fwww.ffn.ub.es%2Fluisnavarro%2Fnuevo_maletin%2FBohr_1913.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-63"><span class="mw-cite-backlink"><b><a href="#cite_ref-63">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKragh1979" class="citation journal cs1"><a href="/wiki/Helge_Kragh" title="Helge Kragh">Kragh, Helge</a> (1979). <a rel="nofollow" class="external text" href="https://www.jstor.org/stable/27757389">"Niels Bohr's Second Atomic Theory"</a>. <i>Historical Studies in the Physical Sciences</i>. <b>10</b>: 123–186. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.2307%2F27757389">10.2307/27757389</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0073-2672">0073-2672</a>. <a href="/wiki/JSTOR_(identifier)" class="mw-redirect" title="JSTOR (identifier)">JSTOR</a> <a rel="nofollow" class="external text" href="https://www.jstor.org/stable/27757389">27757389</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Historical+Studies+in+the+Physical+Sciences&rft.atitle=Niels+Bohr%27s+Second+Atomic+Theory&rft.volume=10&rft.pages=123-186&rft.date=1979&rft.issn=0073-2672&rft_id=https%3A%2F%2Fwww.jstor.org%2Fstable%2F27757389%23id-name%3DJSTOR&rft_id=info%3Adoi%2F10.2307%2F27757389&rft.aulast=Kragh&rft.aufirst=Helge&rft_id=https%3A%2F%2Fwww.jstor.org%2Fstable%2F27757389&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-64"><span class="mw-cite-backlink"><b><a href="#cite_ref-64">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHentschel2009" class="citation book cs1">Hentschel, Klaus (2009). <a rel="nofollow" class="external text" href="https://link.springer.com/10.1007/978-3-540-70626-7_241">"Zeeman Effect"</a>. In Greenberger, Daniel; Hentschel, Klaus; Weinert, Friedel (eds.). <i>Compendium of Quantum Physics</i>. Berlin, Heidelberg: Springer Berlin Heidelberg. pp. 862–864. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2F978-3-540-70626-7_241">10.1007/978-3-540-70626-7_241</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-3-540-70622-9" title="Special:BookSources/978-3-540-70622-9"><bdi>978-3-540-70622-9</bdi></a><span class="reference-accessdate">. Retrieved <span class="nowrap">2023-02-08</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Zeeman+Effect&rft.btitle=Compendium+of+Quantum+Physics&rft.place=Berlin%2C+Heidelberg&rft.pages=862-864&rft.pub=Springer+Berlin+Heidelberg&rft.date=2009&rft_id=info%3Adoi%2F10.1007%2F978-3-540-70626-7_241&rft.isbn=978-3-540-70622-9&rft.aulast=Hentschel&rft.aufirst=Klaus&rft_id=https%3A%2F%2Flink.springer.com%2F10.1007%2F978-3-540-70626-7_241&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-65"><span class="mw-cite-backlink"><b><a href="#cite_ref-65">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFEckert2014" class="citation journal cs1">Eckert, Michael (April 2014). <a rel="nofollow" class="external text" href="http://link.springer.com/10.1140/epjh/e2013-40052-4">"How Sommerfeld extended Bohr's model of the atom (1913–1916)"</a>. <i>The European Physical Journal H</i>. <b>39</b> (2): 141–156. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2014EPJH...39..141E">2014EPJH...39..141E</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1140%2Fepjh%2Fe2013-40052-4">10.1140/epjh/e2013-40052-4</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/2102-6459">2102-6459</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:256006474">256006474</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+European+Physical+Journal+H&rft.atitle=How+Sommerfeld+extended+Bohr%27s+model+of+the+atom+%281913%E2%80%931916%29&rft.volume=39&rft.issue=2&rft.pages=141-156&rft.date=2014-04&rft_id=info%3Adoi%2F10.1140%2Fepjh%2Fe2013-40052-4&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A256006474%23id-name%3DS2CID&rft.issn=2102-6459&rft_id=info%3Abibcode%2F2014EPJH...39..141E&rft.aulast=Eckert&rft.aufirst=Michael&rft_id=http%3A%2F%2Flink.springer.com%2F10.1140%2Fepjh%2Fe2013-40052-4&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-66"><span class="mw-cite-backlink"><b><a href="#cite_ref-66">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://nobelprize.org/nobel_prizes/chemistry/laureates/1921/soddy-bio.html">"Frederick Soddy, The Nobel Prize in Chemistry 1921"</a>. Nobel Foundation<span class="reference-accessdate">. Retrieved <span class="nowrap">2008-01-18</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Frederick+Soddy%2C+The+Nobel+Prize+in+Chemistry+1921&rft.pub=Nobel+Foundation&rft_id=http%3A%2F%2Fnobelprize.org%2Fnobel_prizes%2Fchemistry%2Flaureates%2F1921%2Fsoddy-bio.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-67"><span class="mw-cite-backlink"><b><a href="#cite_ref-67">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFleck1957" class="citation journal cs1">Fleck, Alexander (1957). <a rel="nofollow" class="external text" href="https://doi.org/10.1098%2Frsbm.1957.0014">"Frederick Soddy"</a>. <i>Biographical Memoirs of Fellows of the Royal Society</i>. <b>3</b>: 203–216. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1098%2Frsbm.1957.0014">10.1098/rsbm.1957.0014</a></span>. <q>p. 208: Up to 1913 we used the phrase 'radio elements chemically non-separable' and at that time the word isotope was suggested in a drawing-room discussion with Dr. Margaret Todd in the home of Soddy's father-in-law, Sir <a href="/wiki/George_Beilby" title="George Beilby">George Beilby</a>.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Biographical+Memoirs+of+Fellows+of+the+Royal+Society&rft.atitle=Frederick+Soddy&rft.volume=3&rft.pages=203-216&rft.date=1957&rft_id=info%3Adoi%2F10.1098%2Frsbm.1957.0014&rft.aulast=Fleck&rft.aufirst=Alexander&rft_id=https%3A%2F%2Fdoi.org%2F10.1098%252Frsbm.1957.0014&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-thompson3-68"><span class="mw-cite-backlink"><b><a href="#cite_ref-thompson3_68-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFThomson,_J._J.1913" class="citation journal cs1">Thomson, J. J. (1913). <a rel="nofollow" class="external text" href="http://web.lemoyne.edu/~giunta/canal.html">"Rays of positive electricity"</a>. <i>Proceedings of the Royal Society</i>. <b>A 89</b> (607): 1–20. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1913RSPSA..89....1T">1913RSPSA..89....1T</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1098%2Frspa.1913.0057">10.1098/rspa.1913.0057</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:124295244">124295244</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Proceedings+of+the+Royal+Society&rft.atitle=Rays+of+positive+electricity&rft.volume=A+89&rft.issue=607&rft.pages=1-20&rft.date=1913&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A124295244%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1098%2Frspa.1913.0057&rft_id=info%3Abibcode%2F1913RSPSA..89....1T&rft.au=Thomson%2C+J.+J.&rft_id=http%3A%2F%2Fweb.lemoyne.edu%2F~giunta%2Fcanal.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span> [as excerpted in Henry A. Boorse & Lloyd Motz, <i>The World of the Atom</i>, Vol. 1 (New York: Basic Books, 1966)]. Retrieved on August 29, 2007.</span> </li> <li id="cite_note-69"><span class="mw-cite-backlink"><b><a href="#cite_ref-69">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFlowers2022" class="citation book cs1">Flowers, Paul; et al. (2022). <a rel="nofollow" class="external text" href="https://openstax.org/books/chemistry-2e/pages/21-1-nuclear-structure-and-stability"><i>Chemistry 2e</i></a>. OpenStax. pp. 70–71. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-947172-61-6" title="Special:BookSources/978-1-947172-61-6"><bdi>978-1-947172-61-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Chemistry+2e&rft.pages=70-71&rft.pub=OpenStax&rft.date=2022&rft.isbn=978-1-947172-61-6&rft.aulast=Flowers&rft.aufirst=Paul&rft_id=https%3A%2F%2Fopenstax.org%2Fbooks%2Fchemistry-2e%2Fpages%2F21-1-nuclear-structure-and-stability&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-70"><span class="mw-cite-backlink"><b><a href="#cite_ref-70">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJ._J._Thomson1898" class="citation journal cs1">J. J. Thomson (1898). <a rel="nofollow" class="external text" href="https://archive.org/details/londonedinburgh5461898lon/page/528/mode/2up">"On the Charge of Electricity carried by the Ions produced by Röntgen Rays"</a>. <i>The London, Edinburgh and Dublin Philosophical Magazine and Journal of Science</i>. 5. <b>46</b> (283): 528–545. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1080%2F14786449808621229">10.1080/14786449808621229</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+London%2C+Edinburgh+and+Dublin+Philosophical+Magazine+and+Journal+of+Science&rft.atitle=On+the+Charge+of+Electricity+carried+by+the+Ions+produced+by+R%C3%B6ntgen+Rays&rft.volume=46&rft.issue=283&rft.pages=528-545&rft.date=1898&rft_id=info%3Adoi%2F10.1080%2F14786449808621229&rft.au=J.+J.+Thomson&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Flondonedinburgh5461898lon%2Fpage%2F528%2Fmode%2F2up&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-71"><span class="mw-cite-backlink"><b><a href="#cite_ref-71">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="refRutherford1911" class="citation journal cs1">Ernest Rutherford (1911). <a rel="nofollow" class="external text" href="http://www.chemteam.info/Chem-History/Rutherford-1911/Rutherford-1911.html">"The Scattering of α and β Particles by Matter and the Structure of the Atom"</a>. <i><a href="/wiki/Philosophical_Magazine" title="Philosophical Magazine">Philosophical Magazine</a></i>. Series 6. <b>21</b> (125): 669–688. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1080%2F14786440508637080">10.1080/14786440508637080</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Philosophical+Magazine&rft.atitle=The+Scattering+of+%CE%B1+and+%CE%B2+Particles+by+Matter+and+the+Structure+of+the+Atom&rft.volume=21&rft.issue=125&rft.pages=669-688&rft.date=1911&rft_id=info%3Adoi%2F10.1080%2F14786440508637080&rft.au=Ernest+Rutherford&rft_id=http%3A%2F%2Fwww.chemteam.info%2FChem-History%2FRutherford-1911%2FRutherford-1911.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-72"><span class="mw-cite-backlink"><b><a href="#cite_ref-72">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAntonius_van_den_Broek1911" class="citation journal cs1">Antonius van den Broek (23 June 1911). <a rel="nofollow" class="external text" href="https://www.nature.com/articles/087078b0">"The Number of Possible Elements and Mendeléeff's "Cubic" Periodic System"</a>. <i>Nature</i>. <b>87</b> (2177): 78. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1911Natur..87...78V">1911Natur..87...78V</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2F087078b0">10.1038/087078b0</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=The+Number+of+Possible+Elements+and+Mendel%C3%A9eff%27s+%22Cubic%22+Periodic+System&rft.volume=87&rft.issue=2177&rft.pages=78&rft.date=1911-06-23&rft_id=info%3Adoi%2F10.1038%2F087078b0&rft_id=info%3Abibcode%2F1911Natur..87...78V&rft.au=Antonius+van+den+Broek&rft_id=https%3A%2F%2Fwww.nature.com%2Farticles%2F087078b0&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span><br />"Hence, if this cubic periodic system should prove to be correct, then the number of possible elements is equal to the number of possible permanent charges of each sign per atom, or to each possible permanent charge (of both signs) per atom belongs a possible element."</span> </li> <li id="cite_note-73"><span class="mw-cite-backlink"><b><a href="#cite_ref-73">^</a></b></span> <span class="reference-text">Eric Scerri (2020). <i>The Periodic Table: Its Story and Its Significance</i>, p. 185</span> </li> <li id="cite_note-74"><span class="mw-cite-backlink"><b><a href="#cite_ref-74">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFErnest_Rutherford1914" class="citation journal cs1">Ernest Rutherford (March 1914). <a rel="nofollow" class="external text" href="https://www.chemteam.info/Chem-History/Rutherford-1914.html">"The Structure of the Atom"</a>. <i>Philosophical Magazine</i>. 6. <b>27</b>: 488–498. <q>It is obvious from the consideration of the cases of hydrogen and helium, where hydrogen has one electron and helium two, that the number of electrons cannot be exactly half the atomic weight in all cases. This has led to an interesting suggestion by van den Broek that the number of units of charge on the nucleus, and consequently the number of external electrons, may be equal to the number of the elements when arranged in order of increasing atomic weight.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Philosophical+Magazine&rft.atitle=The+Structure+of+the+Atom&rft.volume=27&rft.pages=488-498&rft.date=1914-03&rft.au=Ernest+Rutherford&rft_id=https%3A%2F%2Fwww.chemteam.info%2FChem-History%2FRutherford-1914.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-75"><span class="mw-cite-backlink"><b><a href="#cite_ref-75">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFErnest_Rutherford1913" class="citation journal cs1">Ernest Rutherford (11 Dec 1913). "The Structure of the Atom". <i>Nature</i>. <b>92</b> (423). <q>The original suggestion of van der Broek that the charge on the nucleus is equal to the atomic number and not to half the atomic weight seems to me very promising.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=The+Structure+of+the+Atom&rft.volume=92&rft.issue=423&rft.date=1913-12-11&rft.au=Ernest+Rutherford&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-76"><span class="mw-cite-backlink"><b><a href="#cite_ref-76">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFRutherford,_Ernest1919" class="citation journal cs1">Rutherford, Ernest (1919). <a rel="nofollow" class="external text" href="http://web.lemoyne.edu/~GIUNTA/rutherford.html">"Collisions of alpha Particles with Light Atoms. IV. An Anomalous Effect in Nitrogen"</a>. <i>Philosophical Magazine</i>. <b>37</b> (222): 581. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1080%2F14786440608635919">10.1080/14786440608635919</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Philosophical+Magazine&rft.atitle=Collisions+of+alpha+Particles+with+Light+Atoms.+IV.+An+Anomalous+Effect+in+Nitrogen&rft.volume=37&rft.issue=222&rft.pages=581&rft.date=1919&rft_id=info%3Adoi%2F10.1080%2F14786440608635919&rft.au=Rutherford%2C+Ernest&rft_id=http%3A%2F%2Fweb.lemoyne.edu%2F~GIUNTA%2Frutherford.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-77"><span class="mw-cite-backlink"><b><a href="#cite_ref-77">^</a></b></span> <span class="reference-text"><i>The Development of the Theory of Atomic Structure</i> (Rutherford 1936). Reprinted in <i>Background to Modern Science: Ten Lectures at Cambridge arranged by the History of Science Committee 1936</i>:<br />"In 1919 I showed that when light atoms were bombarded by α-particles they could be broken up with the emission of a proton, or hydrogen nucleus. We therefore presumed that a proton must be one of the units of which the nuclei of other atoms were composed..."</span> </li> <li id="cite_note-78"><span class="mw-cite-backlink"><b><a href="#cite_ref-78">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFOrme_Masson1921" class="citation journal cs1">Orme Masson (1921). <a rel="nofollow" class="external text" href="https://zenodo.org/records/1430963/files/article.pdf%3Fdownload%3D1&ved=2ahUKEwjN-YzeqIiGAxVyUqQEHaM_COwQFnoECBwQAQ&usg=AOvVaw1G76aUFXByKGSDekUwv2sa">"The Constitution of Atoms"</a>. <i>The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science</i>. <b>41</b> (242): 281–285. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1080%2F14786442108636219">10.1080/14786442108636219</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+London%2C+Edinburgh%2C+and+Dublin+Philosophical+Magazine+and+Journal+of+Science&rft.atitle=The+Constitution+of+Atoms&rft.volume=41&rft.issue=242&rft.pages=281-285&rft.date=1921&rft_id=info%3Adoi%2F10.1080%2F14786442108636219&rft.au=Orme+Masson&rft_id=https%3A%2F%2Fzenodo.org%2Frecords%2F1430963%2Ffiles%2Farticle.pdf%253Fdownload%253D1%26ved%3D2ahUKEwjN-YzeqIiGAxVyUqQEHaM_COwQFnoECBwQAQ%26usg%3DAOvVaw1G76aUFXByKGSDekUwv2sa&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span><br />Footnote by Ernest Rutherford: 'At the time of writing this paper in Australia, Professor Orme Masson was not aware that the name "proton" had already been suggested as a suitable name for the unit of mass nearly 1, in terms of oxygen 16, that appears to enter into the nuclear structure of atoms. The question of a suitable name for this unit was discussed at an informal meeting of a number of members of Section A of the British Association [for the Advancement of Science] at Cardiff this year. The name "baron" suggested by Professor Masson was mentioned, but was considered unsuitable on account of the existing variety of meanings. Finally the name "proton" met with general approval, particularly as it suggests the original term "protyle" given by Prout in his well-known hypothesis that all atoms are built up of hydrogen. The need of a special name for the nuclear unit of mass 1 was drawn attention to by Sir Oliver Lodge at the Sectional meeting, and the writer then suggested the name "proton."'</span> </li> <li id="cite_note-79"><span class="mw-cite-backlink"><b><a href="#cite_ref-79">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHelge_Kragh2000" class="citation journal cs1">Helge Kragh (2000). "Conceptual Changes in Chemistry: The Notion of a Chemical Element, ca. 1900-1925". <i>Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics</i>. <b>31</b> (4): 435–450.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Studies+in+History+and+Philosophy+of+Science+Part+B%3A+Studies+in+History+and+Philosophy+of+Modern+Physics&rft.atitle=Conceptual+Changes+in+Chemistry%3A+The+Notion+of+a+Chemical+Element%2C+ca.+1900-1925&rft.volume=31&rft.issue=4&rft.pages=435-450&rft.date=2000&rft.au=Helge+Kragh&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-80"><span class="mw-cite-backlink"><b><a href="#cite_ref-80">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSir_E._Rutherford1920" class="citation journal cs1">Sir E. Rutherford (1920). <a rel="nofollow" class="external text" href="https://archive.org/details/philtrans03522247/mode/2up?q=doublet">"Bakerian Lecture: Nuclear Constitution of Atoms"</a>. <i>Proceedings of the Royal Society of London. Series A</i>. <b>97</b>: 374–400.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Proceedings+of+the+Royal+Society+of+London.+Series+A&rft.atitle=Bakerian+Lecture%3A+Nuclear+Constitution+of+Atoms&rft.volume=97&rft.pages=374-400&rft.date=1920&rft.au=Sir+E.+Rutherford&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fphiltrans03522247%2Fmode%2F2up%3Fq%3Ddoublet&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span>: "Under some conditions, however, it may be possible for an electron to combine much more closely with the H nucleus, forming a kind of neutral doublet. [...] The existence of such atoms seems almost necessary to explain the building up of the nuclei of heavy elements; for unless we suppose the production of charged particles of very high velocities it is difficult to see how any positively charged particle can reach the nucleus of a heavy atom against its intense repulsive field."</span> </li> <li id="cite_note-81"><span class="mw-cite-backlink"><b><a href="#cite_ref-81">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFChadwick,_James1932" class="citation journal cs1">Chadwick, James (1932). <a rel="nofollow" class="external text" href="http://web.mit.edu/22.54/resources/Chadwick.pdf">"Possible Existence of a Neutron"</a> <span class="cs1-format">(PDF)</span>. <i>Nature</i>. <b>129</b> (3252): 312. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1932Natur.129Q.312C">1932Natur.129Q.312C</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1038%2F129312a0">10.1038/129312a0</a></span>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:4076465">4076465</a>. <a rel="nofollow" class="external text" href="https://ghostarchive.org/archive/20221009/http://web.mit.edu/22.54/resources/Chadwick.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 2022-10-09.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=Possible+Existence+of+a+Neutron&rft.volume=129&rft.issue=3252&rft.pages=312&rft.date=1932&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A4076465%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1038%2F129312a0&rft_id=info%3Abibcode%2F1932Natur.129Q.312C&rft.au=Chadwick%2C+James&rft_id=http%3A%2F%2Fweb.mit.edu%2F22.54%2Fresources%2FChadwick.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-schrodinger-82"><span class="mw-cite-backlink"><b><a href="#cite_ref-schrodinger_82-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSchrödinger,_Erwin1926" class="citation journal cs1">Schrödinger, Erwin (1926). "Quantisation as an Eigenvalue Problem". <i>Annalen der Physik</i>. <b>81</b> (18): 109–139. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1926AnP...386..109S">1926AnP...386..109S</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Fandp.19263861802">10.1002/andp.19263861802</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Annalen+der+Physik&rft.atitle=Quantisation+as+an+Eigenvalue+Problem&rft.volume=81&rft.issue=18&rft.pages=109-139&rft.date=1926&rft_id=info%3Adoi%2F10.1002%2Fandp.19263861802&rft_id=info%3Abibcode%2F1926AnP...386..109S&rft.au=Schr%C3%B6dinger%2C+Erwin&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-Mahanti-83"><span class="mw-cite-backlink"><b><a href="#cite_ref-Mahanti_83-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMahanti,_Subodh" class="citation news cs1">Mahanti, Subodh. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20090417074535/http://www.vigyanprasar.gov.in/scientists/ESchrodinger.htm">"Erwin Schrödinger: The Founder of Quantum Wave Mechanics"</a>. Archived from <a rel="nofollow" class="external text" href="http://www.vigyanprasar.gov.in/scientists/ESchrodinger.htm">the original</a> on 2009-04-17<span class="reference-accessdate">. Retrieved <span class="nowrap">2009-08-01</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.atitle=Erwin+Schr%C3%B6dinger%3A+The+Founder+of+Quantum+Wave+Mechanics&rft.au=Mahanti%2C+Subodh&rft_id=http%3A%2F%2Fwww.vigyanprasar.gov.in%2Fscientists%2FESchrodinger.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-84"><span class="mw-cite-backlink"><b><a href="#cite_ref-84">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMahanti,_Subodh" class="citation news cs1">Mahanti, Subodh. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20090122193755/http://www.vigyanprasar.gov.in/scientists/MBorn.htm">"Max Born: Founder of Lattice Dynamics"</a>. Archived from <a rel="nofollow" class="external text" href="http://www.vigyanprasar.gov.in/scientists/MBorn.htm">the original</a> on 2009-01-22<span class="reference-accessdate">. Retrieved <span class="nowrap">2009-08-01</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.atitle=Max+Born%3A+Founder+of+Lattice+Dynamics&rft.au=Mahanti%2C+Subodh&rft_id=http%3A%2F%2Fwww.vigyanprasar.gov.in%2Fscientists%2FMBorn.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-85"><span class="mw-cite-backlink"><b><a href="#cite_ref-85">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGreiner,_Walter2000" class="citation news cs1">Greiner, Walter (4 October 2000). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=7qCMUfwoQcAC&q=wave-particle+all-particles&pg=PA29">"Quantum Mechanics: An Introduction"</a>. Springer. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9783540674580" title="Special:BookSources/9783540674580"><bdi>9783540674580</bdi></a><span class="reference-accessdate">. Retrieved <span class="nowrap">2010-06-14</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.atitle=Quantum+Mechanics%3A+An+Introduction&rft.date=2000-10-04&rft.isbn=9783540674580&rft.au=Greiner%2C+Walter&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D7qCMUfwoQcAC%26q%3Dwave-particle%2Ball-particles%26pg%3DPA29&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-86"><span class="mw-cite-backlink"><b><a href="#cite_ref-86">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMilton_OrchinRoger_MacomberAllan_PinhasR._Wilson" class="citation news cs1">Milton Orchin; Roger Macomber; Allan Pinhas; R. Wilson. <a rel="nofollow" class="external text" href="http://media.wiley.com/product_data/excerpt/81/04716802/0471680281.pdf">"The Vocabulary and Concepts of Organic Chemistry, Second Edition"</a> <span class="cs1-format">(PDF)</span>. <a rel="nofollow" class="external text" href="https://ghostarchive.org/archive/20221009/http://media.wiley.com/product_data/excerpt/81/04716802/0471680281.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 2022-10-09<span class="reference-accessdate">. Retrieved <span class="nowrap">2010-06-14</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.atitle=The+Vocabulary+and+Concepts+of+Organic+Chemistry%2C+Second+Edition&rft.au=Milton+Orchin&rft.au=Roger+Macomber&rft.au=Allan+Pinhas&rft.au=R.+Wilson&rft_id=http%3A%2F%2Fmedia.wiley.com%2Fproduct_data%2Fexcerpt%2F81%2F04716802%2F0471680281.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-87"><span class="mw-cite-backlink"><b><a href="#cite_ref-87">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFZwiebach2022" class="citation book cs1"><a href="/wiki/Barton_Zwiebach" title="Barton Zwiebach">Zwiebach, Barton</a> (2022). <a rel="nofollow" class="external text" href="https://www.worldcat.org/oclc/1306066387"><i>Mastering Quantum Mechanics Essentials, Theory, and Applications</i></a>. Cambridge: MIT Press. pp. 281–305. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-262-36689-2" title="Special:BookSources/978-0-262-36689-2"><bdi>978-0-262-36689-2</bdi></a>. <a href="/wiki/OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/1306066387">1306066387</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Mastering+Quantum+Mechanics+Essentials%2C+Theory%2C+and+Applications.&rft.place=Cambridge&rft.pages=281-305&rft.pub=MIT+Press&rft.date=2022&rft_id=info%3Aoclcnum%2F1306066387&rft.isbn=978-0-262-36689-2&rft.aulast=Zwiebach&rft.aufirst=Barton&rft_id=https%3A%2F%2Fwww.worldcat.org%2Foclc%2F1306066387&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-88"><span class="mw-cite-backlink"><b><a href="#cite_ref-88">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGrivet2002" class="citation journal cs1">Grivet, Jean-Philippe (January 2002). <a rel="nofollow" class="external text" href="https://pubs.acs.org/doi/abs/10.1021/ed079p127">"The Hydrogen Molecular Ion Revisited"</a>. <i>Journal of Chemical Education</i>. <b>79</b> (1): 127. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2002JChEd..79..127G">2002JChEd..79..127G</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1021%2Fed079p127">10.1021/ed079p127</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0021-9584">0021-9584</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Chemical+Education&rft.atitle=The+Hydrogen+Molecular+Ion+Revisited&rft.volume=79&rft.issue=1&rft.pages=127&rft.date=2002-01&rft.issn=0021-9584&rft_id=info%3Adoi%2F10.1021%2Fed079p127&rft_id=info%3Abibcode%2F2002JChEd..79..127G&rft.aulast=Grivet&rft.aufirst=Jean-Philippe&rft_id=https%3A%2F%2Fpubs.acs.org%2Fdoi%2Fabs%2F10.1021%2Fed079p127&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-89"><span class="mw-cite-backlink"><b><a href="#cite_ref-89">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLevinShertzer1985" class="citation journal cs1">Levin, F. S.; Shertzer, J. (1985-12-01). <a rel="nofollow" class="external text" href="https://link.aps.org/doi/10.1103/PhysRevA.32.3285">"Finite-element solution of the Schrödinger equation for the helium ground state"</a>. <i>Physical Review A</i>. <b>32</b> (6): 3285–3290. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1985PhRvA..32.3285L">1985PhRvA..32.3285L</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1103%2FPhysRevA.32.3285">10.1103/PhysRevA.32.3285</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0556-2791">0556-2791</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/9896495">9896495</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Physical+Review+A&rft.atitle=Finite-element+solution+of+the+Schr%C3%B6dinger+equation+for+the+helium+ground+state&rft.volume=32&rft.issue=6&rft.pages=3285-3290&rft.date=1985-12-01&rft_id=info%3Adoi%2F10.1103%2FPhysRevA.32.3285&rft.issn=0556-2791&rft_id=info%3Apmid%2F9896495&rft_id=info%3Abibcode%2F1985PhRvA..32.3285L&rft.aulast=Levin&rft.aufirst=F.+S.&rft.au=Shertzer%2C+J.&rft_id=https%3A%2F%2Flink.aps.org%2Fdoi%2F10.1103%2FPhysRevA.32.3285&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></span> </li> <li id="cite_note-90"><span class="mw-cite-backlink"><b><a href="#cite_ref-90">^</a></b></span> <span class="reference-text">Karplus, Martin, and Richard Needham Porter. "Atoms and molecules; an introduction for students of physical chemistry." Atoms and molecules; an introduction for students of physical chemistry (1970).</span> </li> </ol></div> <div class="mw-heading mw-heading2"><h2 id="Bibliography">Bibliography</h2></div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFeynmanLeightonSands1963" class="citation book cs1"><a href="/wiki/Richard_Feynman" title="Richard Feynman">Feynman, R.P.</a>; Leighton, R.B.; Sands, M. (1963). <a href="/wiki/The_Feynman_Lectures_on_Physics" title="The Feynman Lectures on Physics"><i>The Feynman Lectures on Physics</i></a>. Vol. 1. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-201-02116-5" title="Special:BookSources/978-0-201-02116-5"><bdi>978-0-201-02116-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Feynman+Lectures+on+Physics&rft.date=1963&rft.isbn=978-0-201-02116-5&rft.aulast=Feynman&rft.aufirst=R.P.&rft.au=Leighton%2C+R.B.&rft.au=Sands%2C+M.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="refMelsen1952" class="citation book cs1">Andrew G. van Melsen (1960) [First published 1952]. <i>From Atomos to Atom: The History of the Concept Atom</i>. Translated by Henry J. Koren. Dover Publications. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-486-49584-1" title="Special:BookSources/0-486-49584-1"><bdi>0-486-49584-1</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=From+Atomos+to+Atom%3A+The+History+of+the+Concept+Atom&rft.pub=Dover+Publications&rft.date=1960&rft.isbn=0-486-49584-1&rft.au=Andrew+G.+van+Melsen&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="refMillington1906" class="citation book cs1">J. P. Millington (1906). <a rel="nofollow" class="external text" href="https://archive.org/details/in.ernet.dli.2015.30924/"><i>John Dalton</i></a>. J. M. Dent & Co. (London); E. P. Dutton & Co. (New York).</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=John+Dalton&rft.pub=J.+M.+Dent+%26+Co.+%28London%29%3B+E.+P.+Dutton+%26+Co.+%28New+York%29&rft.date=1906&rft.au=J.+P.+Millington&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fin.ernet.dli.2015.30924%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="refNavarro2012" class="citation book cs1">Jaume Navarro (2012). <i>A History of the Electron: J. J. and G. P. Thomson</i>. Cambridge University Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-107-00522-8" title="Special:BookSources/978-1-107-00522-8"><bdi>978-1-107-00522-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=A+History+of+the+Electron%3A+J.+J.+and+G.+P.+Thomson&rft.pub=Cambridge+University+Press&rft.date=2012&rft.isbn=978-1-107-00522-8&rft.au=Jaume+Navarro&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="refTrusted1999" class="citation book cs1"><a href="/wiki/Jennifer_Trusted" title="Jennifer Trusted">Trusted, Jennifer</a> (1999). <i>The Mystery of Matter</i>. MacMillan. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-333-76002-6" title="Special:BookSources/0-333-76002-6"><bdi>0-333-76002-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Mystery+of+Matter&rft.pub=MacMillan&rft.date=1999&rft.isbn=0-333-76002-6&rft.aulast=Trusted&rft.aufirst=Jennifer&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="refPullman1998" class="citation book cs1">Bernard Pullman (1998). <i>The Atom in the History of Human Thought</i>. Translated by Axel Reisinger. Oxford University Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-19-511447-7" title="Special:BookSources/0-19-511447-7"><bdi>0-19-511447-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Atom+in+the+History+of+Human+Thought&rft.pub=Oxford+University+Press&rft.date=1998&rft.isbn=0-19-511447-7&rft.au=Bernard+Pullman&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="refPerrin1909" class="citation book cs1">Jean Perrin (1910) [1909]. <a rel="nofollow" class="external text" href="https://archive.org/details/brownianmovement00perr"><i>Brownian Movement and Molecular Reality</i></a>. Translated by F. Soddy. Taylor and Francis.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Brownian+Movement+and+Molecular+Reality&rft.pub=Taylor+and+Francis&rft.date=1910&rft.au=Jean+Perrin&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fbrownianmovement00perr&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFIda_Freund1904" class="citation book cs1">Ida Freund (1904). <i>The Study of Chemical Composition</i>. Cambridge University Press.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Study+of+Chemical+Composition&rft.pub=Cambridge+University+Press&rft.date=1904&rft.au=Ida+Freund&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFThomas_Thomson1807" class="citation book cs1">Thomas Thomson (1807). <i>A System of Chemistry: In Five Volumes, Volume 3</i>. John Brown.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=A+System+of+Chemistry%3A+In+Five+Volumes%2C+Volume+3&rft.pub=John+Brown&rft.date=1807&rft.au=Thomas+Thomson&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFThomas_Thomson1831" class="citation book cs1">Thomas Thomson (1831). <i>The History of Chemistry, Volume 2</i>. H. Colburn, and R. Bentley.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+History+of+Chemistry%2C+Volume+2&rft.pub=H.+Colburn%2C+and+R.+Bentley&rft.date=1831&rft.au=Thomas+Thomson&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="refDalton1808" class="citation book cs1">John Dalton (1808). <a rel="nofollow" class="external text" href="https://library.si.edu/digital-library/book/new-system-chemical-philosophy"><i>A New System of Chemical Philosophy vol. 1</i></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=A+New+System+of+Chemical+Philosophy+vol.+1&rft.date=1808&rft.au=John+Dalton&rft_id=https%3A%2F%2Flibrary.si.edu%2Fdigital-library%2Fbook%2Fnew-system-chemical-philosophy&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="refDalton1817" class="citation book cs1">John Dalton (1817). <a rel="nofollow" class="external text" href="https://library.si.edu/digital-library/book/new-system-chemical-philosophy"><i>A New System of Chemical Philosophy vol. 2</i></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=A+New+System+of+Chemical+Philosophy+vol.+2&rft.date=1817&rft.au=John+Dalton&rft_id=https%3A%2F%2Flibrary.si.edu%2Fdigital-library%2Fbook%2Fnew-system-chemical-philosophy&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFStanislao_Cannizzaro1858" class="citation book cs1">Stanislao Cannizzaro (1858). <a rel="nofollow" class="external text" href="https://archive.org/details/sketchofcourseof00cannrich/page/4/mode/2up?q=Berzelius"><i>Sketch of a Course of Chemical Philosophy</i></a>. The Alembic Club.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Sketch+of+a+Course+of+Chemical+Philosophy&rft.pub=The+Alembic+Club&rft.date=1858&rft.au=Stanislao+Cannizzaro&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fsketchofcourseof00cannrich%2Fpage%2F4%2Fmode%2F2up%3Fq%3DBerzelius&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+of+atomic+theory" class="Z3988"></span></li></ul> <div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2></div> <ul><li><a href="/wiki/Charles_Adolphe_Wurtz" title="Charles Adolphe Wurtz">Charles Adolphe Wurtz</a> (1881) <i>The Atomic Theory</i>, D. Appleton and Company, New York.</li> <li><a href="/w/index.php?title=Alan_J._Rocke&action=edit&redlink=1" class="new" title="Alan J. Rocke (page does not exist)">Alan J. Rocke</a> (1984) <i>Chemical Atomism in the Nineteenth Century: From Dalton to Cannizzaro</i>, Ohio State University Press, Columbus (open access full text at <a rel="nofollow" class="external free" href="http://digital.case.edu/islandora/object/ksl%3Ax633gj985">http://digital.case.edu/islandora/object/ksl%3Ax633gj985</a>).</li></ul> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2></div> <style data-mw-deduplicate="TemplateStyles:r1235681985">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:var(--background-color-interactive-subtle,#f8f9fa);display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .side-box-imageright{padding:2px 0.9em 2px 0;text-align:center}@media(min-width:500px){.mw-parser-output .side-box-flex{display:flex;align-items:center}.mw-parser-output .side-box-text{flex:1;min-width:0}}@media(min-width:720px){.mw-parser-output .side-box{width:238px}.mw-parser-output .side-box-right{clear:right;float:right;margin-left:1em}.mw-parser-output .side-box-left{margin-right:1em}}</style><style data-mw-deduplicate="TemplateStyles:r1237033735">@media print{body.ns-0 .mw-parser-output .sistersitebox{display:none!important}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}</style><div class="side-box side-box-right plainlinks sistersitebox"><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style> <div class="side-box-flex"> <div class="side-box-image"><span class="noviewer" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Wikiquote-logo.svg/34px-Wikiquote-logo.svg.png" decoding="async" width="34" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Wikiquote-logo.svg/51px-Wikiquote-logo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Wikiquote-logo.svg/68px-Wikiquote-logo.svg.png 2x" data-file-width="300" data-file-height="355" /></span></span></div> <div class="side-box-text plainlist">Wikiquote has quotations related to <i><b><a href="https://en.wikiquote.org/wiki/Atomic_theory" class="extiw" title="q:Atomic theory">Atomic theory</a></b></i>.</div></div> </div> <ul><li><a rel="nofollow" class="external text" href="http://faculty.washington.edu/smcohen/320/atomism.htm">Atomism</a> by S. Mark Cohen.</li> <li><a rel="nofollow" class="external text" href="http://www.robotplatform.com/knowledge/Atomic%20Theory/atomic_theory.html">Atomic Theory</a> – detailed information on atomic theory with respect to electrons and electricity.</li> <li><a rel="nofollow" class="external text" href="https://www.feynmanlectures.caltech.edu/I_01.html">The Feynman Lectures on Physics Vol. I Ch. 1: Atoms in Motion</a></li></ul> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist dd::after,.mw-parser-output .hlist li::after{content:" · ";font-weight:bold}.mw-parser-output .hlist dd:last-child::after,.mw-parser-output .hlist dt:last-child::after,.mw-parser-output .hlist li:last-child::after{content:none}.mw-parser-output .hlist dd dd:first-child::before,.mw-parser-output .hlist dd dt:first-child::before,.mw-parser-output .hlist dd li:first-child::before,.mw-parser-output .hlist dt dd:first-child::before,.mw-parser-output .hlist dt dt:first-child::before,.mw-parser-output .hlist dt li:first-child::before,.mw-parser-output .hlist li dd:first-child::before,.mw-parser-output .hlist li dt:first-child::before,.mw-parser-output .hlist li li:first-child::before{content:" (";font-weight:normal}.mw-parser-output .hlist dd dd:last-child::after,.mw-parser-output .hlist dd dt:last-child::after,.mw-parser-output .hlist dd li:last-child::after,.mw-parser-output .hlist dt dd:last-child::after,.mw-parser-output .hlist dt dt:last-child::after,.mw-parser-output .hlist dt li:last-child::after,.mw-parser-output .hlist li dd:last-child::after,.mw-parser-output .hlist li dt:last-child::after,.mw-parser-output .hlist li li:last-child::after{content:")";font-weight:normal}.mw-parser-output .hlist ol{counter-reset:listitem}.mw-parser-output .hlist ol>li{counter-increment:listitem}.mw-parser-output .hlist ol>li::before{content:" "counter(listitem)"\a0 "}.mw-parser-output .hlist dd ol>li:first-child::before,.mw-parser-output .hlist dt ol>li:first-child::before,.mw-parser-output .hlist li ol>li:first-child::before{content:" ("counter(listitem)"\a0 "}</style><style data-mw-deduplicate="TemplateStyles:r1236075235">.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style></div><div role="navigation" class="navbox" aria-labelledby="History_of_physics_(timeline)" style="padding:3px"><table class="nowraplinks hlist mw-collapsible mw-collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:History_of_physics" title="Template:History of physics"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:History_of_physics" title="Template talk:History of physics"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:History_of_physics" title="Special:EditPage/Template:History of physics"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="History_of_physics_(timeline)" style="font-size:114%;margin:0 4em"><a href="/wiki/History_of_physics" title="History of physics">History of physics</a> (<a href="/wiki/Timeline_of_fundamental_physics_discoveries" title="Timeline of fundamental physics discoveries">timeline</a>)</div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Classical_physics" title="Classical physics">Classical physics</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/History_of_astronomy" title="History of astronomy">Astronomy</a> <ul><li><a href="/wiki/Timeline_of_astronomy" title="Timeline of astronomy">timeline</a></li></ul></li> <li><a href="/wiki/History_of_electromagnetic_theory" title="History of electromagnetic theory">Electromagnetism</a> <ul><li><a href="/wiki/Timeline_of_electromagnetism_and_classical_optics" title="Timeline of electromagnetism and classical optics">timeline</a></li> <li><a href="/wiki/History_of_electrical_engineering" title="History of electrical engineering">Electrical engineering</a></li> <li><a href="/wiki/History_of_Maxwell%27s_equations" title="History of Maxwell's equations">Maxwell's equations</a></li></ul></li> <li><a href="/wiki/History_of_fluid_mechanics" title="History of fluid mechanics">Fluid mechanics</a> <ul><li><a href="/wiki/Timeline_of_fluid_and_continuum_mechanics" title="Timeline of fluid and continuum mechanics">timeline</a></li> <li><a href="/wiki/History_of_aerodynamics" title="History of aerodynamics">Aerodynamics</a></li></ul></li> <li><a href="/wiki/History_of_classical_field_theory" title="History of classical field theory">Field theory</a></li> <li><a href="/wiki/History_of_gravitational_theory" title="History of gravitational theory">Gravitational theory</a> <ul><li><a href="/wiki/Timeline_of_gravitational_physics_and_relativity" title="Timeline of gravitational physics and relativity">timeline</a></li></ul></li> <li><a href="/wiki/History_of_materials_science" title="History of materials science">Material science</a> <ul><li><a href="/wiki/Timeline_of_materials_technology" title="Timeline of materials technology">timeline</a></li> <li><a href="/wiki/History_of_metamaterials" title="History of metamaterials">Metamaterials</a></li></ul></li> <li><a href="/wiki/History_of_classical_mechanics" title="History of classical mechanics">Mechanics</a> <ul><li><a href="/wiki/Timeline_of_classical_mechanics" title="Timeline of classical mechanics">timeline</a></li> <li><a href="/wiki/History_of_variational_principles_in_physics" title="History of variational principles in physics">Variational principles</a></li></ul></li> <li><a href="/wiki/History_of_optics" title="History of optics">Optics</a> <ul><li><a href="/wiki/History_of_spectroscopy" title="History of spectroscopy">Spectroscopy</a></li></ul></li> <li><a href="/wiki/History_of_thermodynamics" title="History of thermodynamics">Thermodynamics</a> <ul><li><a href="/wiki/Timeline_of_thermodynamics" title="Timeline of thermodynamics">timeline</a></li> <li><a href="/wiki/History_of_energy" title="History of energy">Energy</a></li> <li><a href="/wiki/History_of_entropy" title="History of entropy">Entropy</a></li> <li><a href="/wiki/History_of_perpetual_motion_machines" title="History of perpetual motion machines">Perpetual motion</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Modern_physics" title="Modern physics">Modern physics</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li>Computational physics <ul><li><a href="/wiki/Timeline_of_computational_physics" title="Timeline of computational physics">timeline</a></li></ul></li> <li>Condensed matter <ul><li><a href="/wiki/Timeline_of_condensed_matter_physics" title="Timeline of condensed matter physics">timeline</a></li> <li><a href="/wiki/History_of_superconductivity" title="History of superconductivity">Superconductivity</a></li></ul></li> <li>Cosmology <ul><li><a href="/wiki/Timeline_of_cosmological_theories" title="Timeline of cosmological theories">timeline</a></li> <li><a href="/wiki/History_of_the_Big_Bang_theory" title="History of the Big Bang theory">Big Bang theory</a></li></ul></li> <li><a href="/wiki/History_of_general_relativity" title="History of general relativity">General relativity</a> <ul><li><a href="/wiki/Tests_of_general_relativity" title="Tests of general relativity">tests</a></li></ul></li> <li><a href="/wiki/History_of_geophysics" title="History of geophysics">Geophysics</a></li> <li>Nuclear physics <ul><li><a href="/wiki/Discovery_of_nuclear_fission" title="Discovery of nuclear fission">Fission</a></li> <li><a href="/wiki/History_of_nuclear_fusion" title="History of nuclear fusion">Fusion</a></li> <li><a href="/wiki/History_of_nuclear_power" title="History of nuclear power">Power</a></li> <li><a href="/wiki/History_of_nuclear_weapons" title="History of nuclear weapons">Weapons</a></li></ul></li> <li><a href="/wiki/History_of_quantum_mechanics" title="History of quantum mechanics">Quantum mechanics</a> <ul><li><a href="/wiki/Timeline_of_quantum_mechanics" title="Timeline of quantum mechanics">timeline</a></li> <li><a class="mw-selflink selflink">Atoms</a></li> <li><a href="/wiki/History_of_molecular_theory" title="History of molecular theory">Molecules</a></li> <li><a href="/wiki/History_of_quantum_field_theory" title="History of quantum field theory">Quantum field theory</a></li></ul></li> <li><a href="/wiki/History_of_subatomic_physics" title="History of subatomic physics">Subatomic physics</a> <ul><li><a href="/wiki/Timeline_of_atomic_and_subatomic_physics" title="Timeline of atomic and subatomic physics">timeline</a></li></ul></li> <li><a href="/wiki/History_of_special_relativity" title="History of special relativity">Special relativity</a> <ul><li><a href="/wiki/Timeline_of_special_relativity_and_the_speed_of_light" title="Timeline of special relativity and the speed of light">timeline</a></li> <li><a href="/wiki/History_of_Lorentz_transformations" title="History of Lorentz transformations">Lorentz transformations</a></li> <li><a href="/wiki/Tests_of_special_relativity" title="Tests of special relativity">tests</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Recent developments</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li>Quantum information <ul><li><a href="/wiki/Timeline_of_quantum_computing_and_communication" title="Timeline of quantum computing and communication">timeline</a></li></ul></li> <li><a href="/wiki/History_of_loop_quantum_gravity" title="History of loop quantum gravity">Loop quantum gravity</a></li> <li><a href="/wiki/History_of_nanotechnology" title="History of nanotechnology">Nanotechnology</a></li> <li><a href="/wiki/History_of_string_theory" title="History of string theory">String theory</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">On specific discoveries</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Discovery_of_cosmic_microwave_background_radiation" title="Discovery of cosmic microwave background radiation">Cosmic microwave background</a></li> <li><a href="/wiki/Discovery_of_graphene" title="Discovery of graphene">Graphene</a></li> <li><a href="/wiki/First_observation_of_gravitational_waves" title="First observation of gravitational waves">Gravitational waves</a></li> <li>Subatomic particles <ul><li><a href="/wiki/Timeline_of_particle_discoveries" title="Timeline of particle discoveries">timeline</a></li> <li><a href="/wiki/Search_for_the_Higgs_boson" title="Search for the Higgs boson">Higgs boson</a></li> <li><a href="/wiki/Discovery_of_the_neutron" title="Discovery of the neutron">Neutron</a></li></ul></li> <li><a href="/wiki/R%C3%B8mer%27s_determination_of_the_speed_of_light" title="Rømer's determination of the speed of light">Speed of light</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">By periods</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Copernican_Revolution" title="Copernican Revolution">Copernican Revolution</a></li> <li><a href="/wiki/Golden_age_of_physics" title="Golden age of physics">Golden age of physics</a></li> <li><a href="/wiki/Golden_age_of_cosmology" title="Golden age of cosmology">Golden age of cosmology</a></li> <li><a href="/wiki/Physics_in_the_medieval_Islamic_world" title="Physics in the medieval Islamic world">Medieval Islamic world</a> <ul><li><a href="/wiki/Astronomy_in_the_medieval_Islamic_world" title="Astronomy in the medieval Islamic world">Astronomy</a></li></ul></li> <li><a href="/wiki/Noisy_intermediate-scale_quantum_era" title="Noisy intermediate-scale quantum era">Noisy intermediate-scale quantum era</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">By groups</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Harvard_Computers" title="Harvard Computers">Harvard Computers</a></li> <li><a href="/wiki/The_Martians_(scientists)" title="The Martians (scientists)">The Martians</a></li> <li><a href="/wiki/Oxford_Calculators" title="Oxford Calculators">Oxford Calculators</a></li> <li><a href="/wiki/Via_Panisperna_boys" title="Via Panisperna boys">Via Panisperna boys</a></li> <li><a href="/wiki/Women_in_physics" title="Women in physics">Women in physics</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Scientific disputes</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Bohr%E2%80%93Einstein_debates" title="Bohr–Einstein debates">Bohr–Einstein</a></li> <li><a href="/wiki/Chandrasekhar%E2%80%93Eddington_dispute" title="Chandrasekhar–Eddington dispute">Chandrasekhar–Eddington</a></li> <li><a href="/wiki/Galileo_affair" title="Galileo affair">Galileo affair</a></li> <li><a href="/wiki/Leibniz%E2%80%93Newton_calculus_controversy" title="Leibniz–Newton calculus controversy">Leibniz–Newton</a></li> <li><a href="/wiki/Mechanical_equivalent_of_heat" title="Mechanical equivalent of heat">Joule–von Mayer</a></li> <li><a href="/wiki/Great_Debate_(astronomy)" title="Great Debate (astronomy)">Shapley–Curtis</a></li> <li>Relativity priority <ul><li><a href="/wiki/Relativity_priority_dispute" title="Relativity priority dispute">Special relativity</a></li> <li><a href="/wiki/General_relativity_priority_dispute" title="General relativity priority dispute">General relativity</a></li></ul></li> <li><a href="/wiki/Transfermium_Wars" title="Transfermium Wars">Transfermium Wars</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Category:History_of_physics" title="Category:History of physics">Category</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="History_of_chemistry_(timeline)" style="padding:3px"><table class="nowraplinks hlist mw-collapsible mw-collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:History_of_chemistry" title="Template:History of chemistry"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/w/index.php?title=Template_talk:History_of_chemistry&action=edit&redlink=1" class="new" title="Template talk:History of chemistry (page does not exist)"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:History_of_chemistry" title="Special:EditPage/Template:History of chemistry"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="History_of_chemistry_(timeline)" style="font-size:114%;margin:0 4em"><a href="/wiki/History_of_chemistry" title="History of chemistry">History of chemistry</a> (<a href="/wiki/Timeline_of_chemistry" title="Timeline of chemistry">timeline</a>)</div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">By branch</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%">Physical chemistry (<a href="/wiki/Timeline_of_physical_chemistry" title="Timeline of physical chemistry">timeline</a>)</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a class="mw-selflink selflink">Atomic theory</a></li> <li><a href="/wiki/History_of_molecular_theory" title="History of molecular theory">Molecular theory</a></li> <li><a href="/wiki/History_of_electrochemistry" title="History of electrochemistry">Electrochemistry</a></li> <li><a href="/wiki/History_of_spectroscopy" title="History of spectroscopy">Spectroscopy</a></li> <li><a href="/wiki/History_of_thermodynamics" title="History of thermodynamics">Thermodynamics</a> <ul><li><a href="/wiki/Timeline_of_thermodynamics" title="Timeline of thermodynamics">timeline</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Organic chemistry (<a href="/wiki/Timeline_of_biology_and_organic_chemistry" title="Timeline of biology and organic chemistry">timeline</a>)</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/History_of_biochemistry" title="History of biochemistry">Biochemistry</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Nuclear chemistry</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Discovery_of_nuclear_fission" title="Discovery of nuclear fission">Fission</a></li> <li><a href="/wiki/History_of_nuclear_fusion" title="History of nuclear fusion">Fusion</a></li> <li><a href="/wiki/History_of_nuclear_power" title="History of nuclear power">Power</a></li> <li><a href="/wiki/History_of_nuclear_weapons" title="History of nuclear weapons">Weapons</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Applied chemistry</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/History_of_cosmetics" title="History of cosmetics">Cosmetics</a></li> <li><a href="/wiki/History_of_materials_science" title="History of materials science">Material science</a></li> <li><a href="/wiki/History_of_nanotechnology" title="History of nanotechnology">Nanotechnology</a></li> <li><a href="/wiki/History_of_pharmacy" title="History of pharmacy">Pharmacy</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Ancient history</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Chinese_alchemy" title="Chinese alchemy">Chinese alchemy</a></li> <li><a href="/wiki/Alchemy_in_the_medieval_Islamic_world" title="Alchemy in the medieval Islamic world">Medieval Islamic World alchemy</a></li> <li><a href="/wiki/History_of_metallurgy_in_the_Indian_subcontinent" title="History of metallurgy in the Indian subcontinent">Indian metallurgy</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/History_of_the_periodic_table" title="History of the periodic table">Periodic table</a> (<a href="/wiki/Discovery_of_chemical_elements" title="Discovery of chemical elements">timeline</a>)</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="By_elements" scope="row" class="navbox-group" style="width:1%">By elements</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/History_of_fluorine" title="History of fluorine">F</a></li> <li><a href="/wiki/History_of_aluminium" title="History of aluminium">Al</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">On specific discoveries</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/History_of_the_battery" title="History of the battery">Battery</a></li> <li>Carbon nanotubes <ul><li><a href="/wiki/Timeline_of_carbon_nanotubes" title="Timeline of carbon nanotubes">timeline</a></li></ul></li> <li><a href="/wiki/History_of_electrophoresis" title="History of electrophoresis">Electrophoresis</a></li> <li><a href="/wiki/History_of_manufactured_fuel_gases" title="History of manufactured fuel gases">Gaseous fuel</a></li> <li><a href="/wiki/Discovery_of_graphene" title="Discovery of graphene">Graphene</a></li> <li><a href="/wiki/History_of_gunpowder" title="History of gunpowder">Gunpowder</a></li> <li><a href="/wiki/History_of_the_Haber_process" title="History of the Haber process">Haber process</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Scientific disputes</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/List_of_chemical_element_naming_controversies" title="List of chemical element naming controversies">Element naming</a></li> <li><a href="/wiki/Mechanical_equivalent_of_heat" title="Mechanical equivalent of heat">Joule–von Mayer</a></li> <li><a href="/wiki/Transfermium_Wars" title="Transfermium Wars">Transfermium Wars</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Other</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Women_in_chemistry" title="Women in chemistry">Women in chemistry</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Category:History_of_chemistry" title="Category:History of chemistry">Category</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Atomic_models" style="padding:3px"><table class="nowraplinks hlist mw-collapsible mw-collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Atomic_models" title="Template:Atomic models"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Atomic_models" title="Template talk:Atomic models"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Atomic_models" title="Special:EditPage/Template:Atomic models"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Atomic_models" style="font-size:114%;margin:0 4em"><a class="mw-selflink selflink">Atomic models</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Historic models</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li>1804 <a href="/wiki/John_Dalton#Atomic_theory" title="John Dalton">Dalton model</a> (billiard ball model)</li> <li>1867 <a href="/wiki/Vortex_theory_of_the_atom" title="Vortex theory of the atom">vortex theory of the atom</a> (knot model)</li> <li>1902 <a href="/wiki/Cubical_atom" title="Cubical atom">Lewis model</a> (cubical atom model)</li> <li>1904 <a href="/wiki/Hantaro_Nagaoka#Saturnian_model_of_the_atom" title="Hantaro Nagaoka">Nagaoka model</a> (Saturnian model)</li> <li>1904 <a href="/wiki/Plum_pudding_model" title="Plum pudding model">plum pudding model</a></li> <li>1911 <a href="/wiki/Rutherford_model" title="Rutherford model">Rutherford model</a> (planetary model)</li> <li>1913 <a href="/wiki/Bohr_model" title="Bohr model">Bohr model</a> (old quantum model)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Current models</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li>1926 <a href="/wiki/Atomic_orbital" title="Atomic orbital">electron cloud model</a></li> <li>1928 <a href="/wiki/Hydrogen-like_atom" title="Hydrogen-like atom">Dirac–Gordon model</a> (relativistic quantum model)</li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Category:Atoms" title="Category:Atoms">Category:Atoms</a></li> <li><span class="noviewer" typeof="mw:File"><a href="/wiki/File:Symbol_portal_class.svg" class="mw-file-description" title="Portal"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/e/e2/Symbol_portal_class.svg/16px-Symbol_portal_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/e/e2/Symbol_portal_class.svg/23px-Symbol_portal_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/e/e2/Symbol_portal_class.svg/31px-Symbol_portal_class.svg.png 2x" data-file-width="180" data-file-height="185" /></a></span> <a href="/wiki/Portal:Physics" title="Portal:Physics">Portal:Physics</a> / <a href="/wiki/Portal:Chemistry" title="Portal:Chemistry">Chemistry</a></li></ul> </div></td></tr></tbody></table></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=History_of_atomic_theory&oldid=1257505012">https://en.wikipedia.org/w/index.php?title=History_of_atomic_theory&oldid=1257505012</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Help:Category" title="Help:Category">Categories</a>: <ul><li><a href="/wiki/Category:Atomic_physics" title="Category:Atomic physics">Atomic physics</a></li><li><a href="/wiki/Category:Amount_of_substance" title="Category:Amount of substance">Amount of substance</a></li><li><a href="/wiki/Category:Chemistry_theories" title="Category:Chemistry theories">Chemistry theories</a></li><li><a href="/wiki/Category:Foundational_quantum_physics" title="Category:Foundational quantum physics">Foundational quantum physics</a></li><li><a href="/wiki/Category:Statistical_mechanics" title="Category:Statistical mechanics">Statistical mechanics</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">Hidden categories: <ul><li><a href="/wiki/Category:Articles_with_short_description" title="Category:Articles with short description">Articles with short description</a></li><li><a href="/wiki/Category:Short_description_is_different_from_Wikidata" title="Category:Short description is different from Wikidata">Short description is different from Wikidata</a></li><li><a href="/wiki/Category:Wikipedia_pages_semi-protected_against_vandalism" title="Category:Wikipedia pages semi-protected against vandalism">Wikipedia pages semi-protected against vandalism</a></li><li><a href="/wiki/Category:Good_articles" title="Category:Good articles">Good articles</a></li><li><a href="/wiki/Category:All_articles_with_unsourced_statements" title="Category:All articles with unsourced statements">All articles with unsourced statements</a></li><li><a href="/wiki/Category:Articles_with_unsourced_statements_from_October_2024" title="Category:Articles with unsourced statements from October 2024">Articles with unsourced statements from October 2024</a></li><li><a href="/wiki/Category:Pages_using_multiple_image_with_auto_scaled_images" title="Category:Pages using multiple image with auto scaled images">Pages using multiple image with auto scaled images</a></li><li><a href="/wiki/Category:Articles_needing_cleanup_from_November_2024" title="Category:Articles needing cleanup from November 2024">Articles needing cleanup from November 2024</a></li><li><a href="/wiki/Category:All_pages_needing_cleanup" title="Category:All pages needing cleanup">All pages needing cleanup</a></li><li><a href="/wiki/Category:Articles_with_sections_that_need_to_be_turned_into_prose_from_November_2024" title="Category:Articles with sections that need to be turned into prose from November 2024">Articles with sections that need to be turned into prose from November 2024</a></li></ul></div></div> </div> </main> </div> <div class="mw-footer-container"> <footer id="footer" class="mw-footer" > <ul id="footer-info"> <li id="footer-info-lastmod"> This page was last edited on 15 November 2024, at 07:20<span class="anonymous-show"> (UTC)</span>.</li> <li id="footer-info-copyright">Text is available under the <a href="/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License" title="Wikipedia:Text of the Creative Commons Attribution-ShareAlike 4.0 International License">Creative Commons Attribution-ShareAlike 4.0 License</a>; additional terms may apply. By using this site, you agree to the <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Terms_of_Use" class="extiw" title="foundation:Special:MyLanguage/Policy:Terms of Use">Terms of Use</a> and <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy" class="extiw" title="foundation:Special:MyLanguage/Policy:Privacy policy">Privacy Policy</a>. Wikipedia® is a registered trademark of the <a rel="nofollow" class="external text" href="https://wikimediafoundation.org/">Wikimedia Foundation, Inc.</a>, a non-profit organization.</li> </ul> <ul id="footer-places"> <li id="footer-places-privacy"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy">Privacy policy</a></li> <li id="footer-places-about"><a href="/wiki/Wikipedia:About">About Wikipedia</a></li> <li id="footer-places-disclaimers"><a href="/wiki/Wikipedia:General_disclaimer">Disclaimers</a></li> <li id="footer-places-contact"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us">Contact Wikipedia</a></li> <li id="footer-places-wm-codeofconduct"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct">Code of Conduct</a></li> <li id="footer-places-developers"><a href="https://developer.wikimedia.org">Developers</a></li> <li id="footer-places-statslink"><a href="https://stats.wikimedia.org/#/en.wikipedia.org">Statistics</a></li> <li id="footer-places-cookiestatement"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement">Cookie statement</a></li> <li id="footer-places-mobileview"><a href="//en.m.wikipedia.org/w/index.php?title=History_of_atomic_theory&mobileaction=toggle_view_mobile" class="noprint stopMobileRedirectToggle">Mobile view</a></li> </ul> <ul id="footer-icons" class="noprint"> <li id="footer-copyrightico"><a href="https://wikimediafoundation.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/static/images/footer/wikimedia-button.svg" width="84" height="29" alt="Wikimedia Foundation" loading="lazy"></a></li> <li id="footer-poweredbyico"><a href="https://www.mediawiki.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/w/resources/assets/poweredby_mediawiki.svg" alt="Powered by MediaWiki" width="88" height="31" loading="lazy"></a></li> </ul> </footer> </div> </div> </div> <div class="vector-settings" id="p-dock-bottom"> <ul></ul> </div><script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.codfw.main-f69cdc8f6-hchr7","wgBackendResponseTime":146,"wgPageParseReport":{"limitreport":{"cputime":"1.348","walltime":"1.606","ppvisitednodes":{"value":9936,"limit":1000000},"postexpandincludesize":{"value":203956,"limit":2097152},"templateargumentsize":{"value":9184,"limit":2097152},"expansiondepth":{"value":16,"limit":100},"expensivefunctioncount":{"value":25,"limit":500},"unstrip-depth":{"value":1,"limit":20},"unstrip-size":{"value":261129,"limit":5000000},"entityaccesscount":{"value":0,"limit":400},"timingprofile":["100.00% 1404.208 1 -total"," 34.13% 479.220 2 Template:Reflist"," 15.04% 211.231 21 Template:Cite_book"," 11.21% 157.399 29 Template:Cite_journal"," 9.20% 129.217 5 Template:Navbox"," 8.06% 113.145 1 Template:History_of_physics"," 7.95% 111.586 1 Template:Short_description"," 7.87% 110.566 11 Template:Cn"," 6.70% 94.094 12 Template:Rp"," 6.10% 85.652 12 Template:R/superscript"]},"scribunto":{"limitreport-timeusage":{"value":"0.793","limit":"10.000"},"limitreport-memusage":{"value":10212383,"limit":52428800},"limitreport-logs":"anchor_id_list = table#1 {\n [\"CITEREFAntonius_van_den_Broek1911\"] = 1,\n [\"CITEREFAvogadro,_Amedeo1811\"] = 1,\n [\"CITEREFAvogadro1811\"] = 1,\n [\"CITEREFBohr,_Niels1913\"] = 1,\n [\"CITEREFBritoRodríguezNiaz2005\"] = 1,\n [\"CITEREFChadwick,_James1932\"] = 1,\n [\"CITEREFDeltete1999\"] = 1,\n [\"CITEREFEckert2014\"] = 1,\n [\"CITEREFEric_Scerri2017\"] = 1,\n [\"CITEREFErnest_Rutherford1913\"] = 1,\n [\"CITEREFErnest_Rutherford1914\"] = 1,\n [\"CITEREFFeynmanLeightonSands1963\"] = 1,\n [\"CITEREFFleck1957\"] = 1,\n [\"CITEREFFlowers2022\"] = 1,\n [\"CITEREFGiora_HonBernard_R._Goldstein2013\"] = 1,\n [\"CITEREFGreiner,_Walter2000\"] = 1,\n [\"CITEREFGrivet2002\"] = 1,\n [\"CITEREFHeilbron1968\"] = 1,\n [\"CITEREFHelge_Kragh2000\"] = 1,\n [\"CITEREFHentschel2009\"] = 1,\n [\"CITEREFIda_Freund1904\"] = 1,\n [\"CITEREFJ._J._Thomson1897\"] = 1,\n [\"CITEREFJ._J._Thomson1898\"] = 2,\n [\"CITEREFJ._J._Thomson1899\"] = 1,\n [\"CITEREFJ._J._Thomson1904\"] = 1,\n [\"CITEREFKragh1979\"] = 1,\n [\"CITEREFLevinShertzer1985\"] = 1,\n [\"CITEREFMahanti,_Subodh\"] = 2,\n [\"CITEREFMilton_OrchinRoger_MacomberAllan_PinhasR._Wilson\"] = 1,\n [\"CITEREFOlenickApostolGoodstein1986\"] = 1,\n [\"CITEREFOrme_Masson1921\"] = 1,\n [\"CITEREFPais2002\"] = 1,\n [\"CITEREFPullman1998\"] = 1,\n [\"CITEREFRutherford,_Ernest1919\"] = 1,\n [\"CITEREFScerri2020\"] = 1,\n [\"CITEREFSchrödinger,_Erwin1926\"] = 1,\n [\"CITEREFSir_E._Rutherford1920\"] = 1,\n [\"CITEREFStanislao_Cannizzaro1858\"] = 1,\n [\"CITEREFThomas_Thomson1807\"] = 1,\n [\"CITEREFThomas_Thomson1831\"] = 1,\n [\"CITEREFThomson,_J._J.1913\"] = 1,\n [\"CITEREFWhittaker1989\"] = 1,\n [\"CITEREFZwiebach2022\"] = 1,\n [\"Dalton\"] = 1,\n [\"refDalton1808\"] = 1,\n [\"refDalton1817\"] = 1,\n [\"refMelsen1952\"] = 1,\n [\"refMillington1906\"] = 1,\n [\"refNavarro2012\"] = 1,\n [\"refPerrin1909\"] = 1,\n [\"refPullman1998\"] = 1,\n [\"refRutherford1911\"] = 1,\n [\"refTrusted1999\"] = 1,\n}\ntemplate_list = table#1 {\n [\"!\"] = 1,\n [\"-\"] = 2,\n [\"About\"] = 1,\n [\"Anchor\"] = 1,\n [\"Atomic models\"] = 1,\n [\"Blockquote\"] = 1,\n [\"Cite book\"] = 21,\n [\"Cite journal\"] = 29,\n [\"Cite news\"] = 4,\n [\"Cite web\"] = 3,\n [\"Cn\"] = 11,\n [\"Crossreference\"] = 1,\n [\"DEFAULTSORT:Atomic Theory, History of\"] = 1,\n [\"Div col\"] = 1,\n [\"Div col end\"] = 1,\n [\"Efn\"] = 1,\n [\"Good article\"] = 1,\n [\"Harvnb\"] = 1,\n [\"History of chemistry\"] = 1,\n [\"History of physics\"] = 1,\n [\"ISBN\"] = 1,\n [\"Main\"] = 7,\n [\"Multiple image\"] = 2,\n [\"Notelist\"] = 1,\n [\"Pi\"] = 1,\n [\"Portal\"] = 1,\n [\"Pp-vandalism\"] = 1,\n [\"Prose\"] = 1,\n [\"Redirect\"] = 1,\n [\"Reflist\"] = 1,\n [\"Rp\"] = 12,\n [\"See also\"] = 1,\n [\"Short description\"] = 1,\n [\"Wikiquote\"] = 1,\n}\narticle_whitelist = table#1 {\n}\n"},"cachereport":{"origin":"mw-web.codfw.main-f69cdc8f6-9j6r5","timestamp":"20241122140702","ttl":2592000,"transientcontent":false}}});});</script> <script type="application/ld+json">{"@context":"https:\/\/schema.org","@type":"Article","name":"History of atomic theory","url":"https:\/\/en.wikipedia.org\/wiki\/History_of_atomic_theory","sameAs":"http:\/\/www.wikidata.org\/entity\/Q210553","mainEntity":"http:\/\/www.wikidata.org\/entity\/Q210553","author":{"@type":"Organization","name":"Contributors to Wikimedia projects"},"publisher":{"@type":"Organization","name":"Wikimedia Foundation, Inc.","logo":{"@type":"ImageObject","url":"https:\/\/www.wikimedia.org\/static\/images\/wmf-hor-googpub.png"}},"datePublished":"2002-02-25T15:51:15Z","dateModified":"2024-11-15T07:20:12Z","image":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/2\/23\/Helium_atom_QM.svg","headline":"history of scientific theory that views matter as made up of atoms of chemical elements"}</script> </body> </html>