Nuclear Chemistry I | Chemistry

<!DOCTYPE html> <html lang="en" dir="ltr"> <head>  <meta http-equiv="X-UA-Compatible" content="ie=edge"> <meta charset="utf-8"> <base href="https://www.visionlearning.com"> <title>Nuclear Chemistry I | Chemistry | Visionlearning</title> <link rel="canonical" href="https://www.visionlearning.com/en/library/chemistry/1/nuclear-chemistry-i/284"> <meta name="description" content="This module explores radioisotopes resulting from unstable atomic nuclei. You will learn how they decay to give off particles and energy. You will also see how alpha, beta, and gamma radioactive decay can be represented by nuclear equation models. Decay chains can be represented as a series of nuclear equations. Knowing the forms of decay and the half-lives of radioisotopes, applications in radiometric dating and radiation therapy for cancer are discussed."> <meta name="keywords" content="radioactivity, radioactive, radiation, atomic, isotope, isotopes, marie curie, particles, radioactive decay, radioisotopes, radiometric dating, nuclear equation, nuclear"> <meta name="viewport" content="width=device-width, initial-scale=1.0, shrink-to-fit=no"> <meta name="msvalidate.01" content="D8E20F39AD48052260032E56DE409970"> <script type="application/ld+json"> { "@context": "http://schema.org/", "@type": "Article", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://visionlearning.com/en/library/chemistry/1/nuclear-chemistry-i/284" }, "name": "Nuclear Chemistry I", "headline": "Nuclear Chemistry I: Radiation, half-life, and nuclear reactions", "author": { "@type": "Person", "name": "Judi Luepke, PhD." }, "datePublished": "2024-08-23 11:18:55", "dateModified": "2017-02-12T08:30:00+05:00", "image": { "@type": "ImageObject", "url": "https://www.visionlearning.com/images/categories/chemistry.jpg", "width": 696, "height": 464 }, "publisher": { "@type": "Organization", "name": "Visionlearning, Inc.", "logo": { "@type": "ImageObject", "url": "http://visionlearning.com/images/logo.png", "width": 278, "height": 60 } }, "description": "This module explores radioisotopes resulting from unstable atomic nuclei. You will learn how they decay to give off particles and energy. You will also see how alpha, beta, and gamma radioactive decay can be represented by nuclear equation models. Decay chains can be represented as a series of nuclear equations. Knowing the forms of decay and the half-lives of radioisotopes, applications in radiometric dating and radiation therapy for cancer are discussed.", "keywords": "radioactivity, radioactive, radiation, atomic, isotope, isotopes, marie curie, particles, radioactive decay, radioisotopes, radiometric dating, nuclear equation, nuclear", "inLanguage": { "@type": "Language", "name": "English", "alternateName": "en" }, "copyrightHolder": { "@type": "Organization", "name": "Visionlearning, Inc." }, "copyrightYear": "2024"} </script> <meta property="og:url" content="https://visionlearning.com/en/library/chemistry/1/nuclear-chemistry-i/284"> <meta property="og:title" content="Nuclear Chemistry I | Chemistry | Visionlearning" /> <meta property="og:type" content="website"> <meta property="og:site_name" content="Visionlearning"> <meta property="og:description" content="This module explores radioisotopes resulting from unstable atomic nuclei. You will learn how they decay to give off particles and energy. You will also see how alpha, beta, and gamma radioactive decay can be represented by nuclear equation models. Decay chains can be represented as a series of nuclear equations. Knowing the forms of decay and the half-lives of radioisotopes, applications in radiometric dating and radiation therapy for cancer are discussed."> <meta property="og:image" content="https://visionlearning.com/images/logo.png"> <meta property="fb:admins" content="100000299664514"> <link rel="stylesheet" type="text/css" href="/css/visionlearning.css">  <link rel="stylesheet" type="text/css" href="/css/visionlearning-icons.css">  <link rel="preload" href="https://fonts.gstatic.com"> <link rel="preload" href="https://fonts.googleapis.com/css2?family=Open+Sans:ital,wght@0,400;0,700;1,400;1,700&family=Schoolbell&display=swap"> <style> textarea.myEditor { width: 90%; height: 350px; } </style> <script type="text/x-mathjax-config" src="/js/mathjax-config.js"></script> <script id="MathJax-script" async src="/js/mathjax/tex-svg.js"></script> <script async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js?client=ca-pub-9561344156007092" crossorigin="anonymous"></script> </head> 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href="/en/library/earth-science/6/ocean-currents/282">Ocean Currents</a></li> <li><a href="/en/library/earth-science/6/water-in-the-atmosphere/289">Water in the Atmosphere</a></li> <li><a href="/en/library/earth-science/6/weather-fronts-and-forecasts/303">Weather, Fronts, and Forecasts</a></li> <li><a href="/en/library/earth-science/6/history-of-earths-atmosphere-i/202">History of Earth's Atmosphere I</a></li> <li><a href="/en/library/earth-science/6/history-of-earths-atmosphere-ii/203">History of Earth's Atmosphere II</a></li> <li><a href="/en/library/earth-science/6/earths-atmosphere/107">Earth's Atmosphere</a></li> <li><a href="/en/library/earth-science/6/factors-that-control-earths-temperature/234">Factors that Control Earth's Temperature</a></li> <li><a href="/en/library/earth-science/6/circulation-in-the-atmosphere/255">Circulation in the Atmosphere</a></li> </ul> </div> <button class="accordion__button" id="acc-button-hazards" data-accordion="button" aria-controls="acc-panel-hazards" aria-expanded="false"> <span class="accordion__button__label"> Hazards </span> </button> <div class="accordion__panel" id="acc-panel-hazards" data-accordion="panel" aria-labelledby="acc-button-hazards" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/earth-science/6/natural-hazards-and-risk/288">Natural Hazards and Risk</a></li> </ul> </div> <button class="accordion__button" id="acc-button-earth-history" data-accordion="button" aria-controls="acc-panel-earth-history" aria-expanded="false"> <span class="accordion__button__label"> Earth History </span> </button> <div class="accordion__panel" id="acc-panel-earth-history" data-accordion="panel" aria-labelledby="acc-button-earth-history" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/earth-science/6/extinction/295">Extinction</a></li> <li><a href="/en/library/earth-science/6/mass-extinctions/294">Mass Extinctions</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-environmental-science" data-accordion="button" aria-controls="acc-panel-environmental-science" aria-expanded="false"> <span class="accordion__button__label"> Environmental Science </span> </button> <div class="accordion__panel" id="acc-panel-environmental-science" data-accordion="panel" aria-labelledby="acc-button-environmental-science" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-ecology" data-accordion="button" aria-controls="acc-panel-ecology" aria-expanded="false"> <span class="accordion__button__label"> Ecology </span> </button> <div class="accordion__panel" id="acc-panel-ecology" data-accordion="panel" aria-labelledby="acc-button-ecology" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/environmental-science/61/biodiversity-i/276">Biodiversity I</a></li> <li><a href="/en/library/environmental-science/61/biodiversity-ii/281">Biodiversity II</a></li> <li><a href="/en/library/environmental-science/61/ecosystem-services/279">Ecosystem Services</a></li> <li><a href="/en/library/environmental-science/61/population-biology/287">Population Biology</a></li> </ul> </div> <button class="accordion__button" id="acc-button-earth-cycles" data-accordion="button" aria-controls="acc-panel-earth-cycles" aria-expanded="false"> <span class="accordion__button__label"> Earth Cycles </span> </button> <div class="accordion__panel" id="acc-panel-earth-cycles" data-accordion="panel" aria-labelledby="acc-button-earth-cycles" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/environmental-science/61/the-nitrogen-cycle/98">The Nitrogen Cycle</a></li> <li><a href="/en/library/environmental-science/61/the-carbon-cycle/95">The Carbon Cycle</a></li> <li><a href="/en/library/environmental-science/61/the-phosphorus-cycle/197">The Phosphorus Cycle</a></li> </ul> </div> <button class="accordion__button" id="acc-button-scientific-research" data-accordion="button" aria-controls="acc-panel-scientific-research" aria-expanded="false"> <span class="accordion__button__label"> Scientific Research </span> </button> <div class="accordion__panel" id="acc-panel-scientific-research" data-accordion="panel" aria-labelledby="acc-button-scientific-research" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/environmental-science/61/collaborative-research-in-the-arctic-towards-understanding-climate-change/183">Collaborative Research in the Arctic Towards Understanding Climate Change</a></li> <li><a href="/en/library/environmental-science/61/atmospheric-chemistry-research-that-changed-global-policy/211">Atmospheric Chemistry Research that Changed Global Policy</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-general-science" data-accordion="button" aria-controls="acc-panel-general-science" aria-expanded="false"> <span class="accordion__button__label"> General Science </span> </button> <div class="accordion__panel" id="acc-panel-general-science" data-accordion="panel" aria-labelledby="acc-button-general-science" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-methods" data-accordion="button" aria-controls="acc-panel-methods" aria-expanded="false"> <span class="accordion__button__label"> Methods </span> </button> <div class="accordion__panel" id="acc-panel-methods" data-accordion="panel" aria-labelledby="acc-button-methods" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/general-science/3/the-scientific-method/45">The Scientific Method</a></li> </ul> </div> <button class="accordion__button" id="acc-button-measurement" data-accordion="button" aria-controls="acc-panel-measurement" aria-expanded="false"> <span class="accordion__button__label"> Measurement </span> </button> <div class="accordion__panel" id="acc-panel-measurement" data-accordion="panel" aria-labelledby="acc-button-measurement" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/general-science/3/the-metric-system/47">The Metric System</a></li> </ul> </div> <button class="accordion__button" id="acc-button-physical-properties" data-accordion="button" aria-controls="acc-panel-physical-properties" aria-expanded="false"> <span class="accordion__button__label"> Physical Properties </span> </button> <div class="accordion__panel" id="acc-panel-physical-properties" data-accordion="panel" aria-labelledby="acc-button-physical-properties" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/general-science/3/temperature/48">Temperature</a></li> <li><a href="/en/library/general-science/3/density-and-buoyancy/37">Density and Buoyancy</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-math-in-science" data-accordion="button" aria-controls="acc-panel-math-in-science" aria-expanded="false"> <span class="accordion__button__label"> Math in Science </span> </button> <div class="accordion__panel" id="acc-panel-math-in-science" data-accordion="panel" aria-labelledby="acc-button-math-in-science" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-equations" data-accordion="button" aria-controls="acc-panel-equations" aria-expanded="false"> <span class="accordion__button__label"> Equations </span> </button> <div class="accordion__panel" id="acc-panel-equations" data-accordion="panel" aria-labelledby="acc-button-equations" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/math-in-science/62/unit-conversion/144">Unit Conversion</a></li> <li><a href="/en/library/math-in-science/62/linear-equations/194">Linear Equations</a></li> <li><a href="/en/library/math-in-science/62/exponential-equations-i/206">Exponential Equations I</a></li> <li><a href="/en/library/math-in-science/62/exponential-equations-ii/210">Exponential Equations II</a></li> <li><a href="/en/library/math-in-science/62/scientific-notation/250">Scientific Notation</a></li> <li><a href="/en/library/math-in-science/62/measurement/257">Measurement</a></li> </ul> </div> <button class="accordion__button" id="acc-button-statistics" data-accordion="button" aria-controls="acc-panel-statistics" aria-expanded="false"> <span class="accordion__button__label"> Statistics </span> </button> <div class="accordion__panel" id="acc-panel-statistics" data-accordion="panel" aria-labelledby="acc-button-statistics" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/math-in-science/62/introduction-to-descriptive-statistics/218">Introduction to Descriptive Statistics</a></li> <li><a href="/en/library/math-in-science/62/introduction-to-inferential-statistics/224">Introduction to Inferential Statistics</a></li> <li><a href="/en/library/math-in-science/62/statistical-techniques/239">Statistical Techniques</a></li> </ul> </div> <button class="accordion__button" id="acc-button-trigonometric-functions" data-accordion="button" aria-controls="acc-panel-trigonometric-functions" aria-expanded="false"> <span class="accordion__button__label"> Trigonometric Functions </span> </button> <div class="accordion__panel" id="acc-panel-trigonometric-functions" data-accordion="panel" aria-labelledby="acc-button-trigonometric-functions" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/math-in-science/62/wave-mathematics/131">Wave Mathematics</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-physics" data-accordion="button" aria-controls="acc-panel-physics" aria-expanded="false"> <span class="accordion__button__label"> Physics </span> </button> <div class="accordion__panel" id="acc-panel-physics" data-accordion="panel" aria-labelledby="acc-button-physics" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-light-and-optics" data-accordion="button" aria-controls="acc-panel-light-and-optics" aria-expanded="false"> <span class="accordion__button__label"> Light and Optics </span> </button> <div class="accordion__panel" id="acc-panel-light-and-optics" data-accordion="panel" aria-labelledby="acc-button-light-and-optics" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/physics/24/the-nature-of-light/132">The Nature of Light</a></li> <li><a href="/en/library/physics/24/electromagnetism-and-light/138">Electromagnetism and Light</a></li> </ul> </div> <button class="accordion__button" id="acc-button-mechanics" data-accordion="button" aria-controls="acc-panel-mechanics" aria-expanded="false"> <span class="accordion__button__label"> Mechanics </span> </button> <div class="accordion__panel" id="acc-panel-mechanics" data-accordion="panel" aria-labelledby="acc-button-mechanics" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/physics/24/defining-energy/199">Defining Energy</a></li> <li><a href="/en/library/physics/24/waves-and-wave-motion/102">Waves and Wave Motion</a></li> <li><a href="/en/library/physics/24/gravity/118">Gravity</a></li> <li><a href="/en/library/physics/24/thermodynamics-i/200">Thermodynamics I</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-process-of-science" data-accordion="button" aria-controls="acc-panel-process-of-science" aria-expanded="false"> <span class="accordion__button__label"> Process of Science </span> </button> <div class="accordion__panel" id="acc-panel-process-of-science" data-accordion="panel" aria-labelledby="acc-button-process-of-science" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-introduction" data-accordion="button" aria-controls="acc-panel-introduction" aria-expanded="false"> <span class="accordion__button__label"> Introduction </span> </button> <div class="accordion__panel" id="acc-panel-introduction" data-accordion="panel" aria-labelledby="acc-button-introduction" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/the-process-of-science/176">The Process of Science</a></li> </ul> </div> <button class="accordion__button" id="acc-button-the-culture-of-science" data-accordion="button" aria-controls="acc-panel-the-culture-of-science" aria-expanded="false"> <span class="accordion__button__label"> The Culture of Science </span> </button> <div class="accordion__panel" id="acc-panel-the-culture-of-science" data-accordion="panel" aria-labelledby="acc-button-the-culture-of-science" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/the-nature-of-scientific-knowledge/185">The Nature of Scientific Knowledge</a></li> <li><a href="/en/library/process-of-science/49/scientists-and-the-scientific-community/172">Scientists and the Scientific Community</a></li> <li><a href="/en/library/process-of-science/49/scientific-ethics/161">Scientific Ethics</a></li> <li><a href="/en/library/process-of-science/49/scientific-institutions-and-societies/162">Scientific Institutions and Societies</a></li> </ul> </div> <button class="accordion__button" id="acc-button-ideas-in-science" data-accordion="button" aria-controls="acc-panel-ideas-in-science" aria-expanded="false"> <span class="accordion__button__label"> Ideas in Science </span> </button> <div class="accordion__panel" id="acc-panel-ideas-in-science" data-accordion="panel" aria-labelledby="acc-button-ideas-in-science" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/theories-hypotheses-and-laws/177">Theories, Hypotheses, and Laws</a></li> <li><a href="/en/library/process-of-science/49/scientific-controversy/181">Scientific Controversy</a></li> <li><a href="/en/library/process-of-science/49/creativity-in-science/182">Creativity in Science</a></li> </ul> </div> <button class="accordion__button" id="acc-button-research-methods" data-accordion="button" aria-controls="acc-panel-research-methods" aria-expanded="false"> <span class="accordion__button__label"> Research Methods </span> </button> <div class="accordion__panel" id="acc-panel-research-methods" data-accordion="panel" aria-labelledby="acc-button-research-methods" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/the-practice-of-science/148">The Practice of Science</a></li> <li><a href="/en/library/process-of-science/49/experimentation-in-scientific-research/150">Experimentation in Scientific Research</a></li> <li><a href="/en/library/process-of-science/49/description-in-scientific-research/151">Description in Scientific Research</a></li> <li><a href="/en/library/process-of-science/49/comparison-in-scientific-research/152">Comparison in Scientific Research</a></li> <li><a href="/en/library/process-of-science/49/modeling-in-scientific-research/153">Modeling in Scientific Research</a></li> </ul> </div> <button class="accordion__button" id="acc-button-data" data-accordion="button" aria-controls="acc-panel-data" aria-expanded="false"> <span class="accordion__button__label"> Data </span> </button> <div class="accordion__panel" id="acc-panel-data" data-accordion="panel" aria-labelledby="acc-button-data" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/data-analysis-and-interpretation/154">Data Analysis and Interpretation</a></li> <li><a href="/en/library/process-of-science/49/uncertainty-error-and-confidence/157">Uncertainty, Error, and Confidence</a></li> <li><a href="/en/library/process-of-science/49/statistics-in-science/155">Statistics in Science</a></li> <li><a href="/en/library/process-of-science/49/using-graphs-and-visual-data-in-science/156">Using Graphs and Visual Data in Science</a></li> </ul> </div> <button class="accordion__button" id="acc-button-scientific-communication" data-accordion="button" aria-controls="acc-panel-scientific-communication" aria-expanded="false"> <span class="accordion__button__label"> Scientific Communication </span> </button> <div class="accordion__panel" id="acc-panel-scientific-communication" data-accordion="panel" aria-labelledby="acc-button-scientific-communication" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/understanding-scientific-journals-and-articles/158">Understanding Scientific Journals and Articles</a></li> <li><a href="/en/library/process-of-science/49/utilizing-the-scientific-literature/173">Utilizing the Scientific Literature</a></li> <li><a href="/en/library/process-of-science/49/peer-review-in-scientific-publishing/159">Peer Review in Scientific Publishing</a></li> <li><a href="/en/library/process-of-science/49/the-how-and-why-of-scientific-meetings/186">The How and Why of Scientific Meetings</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-scientists-and-research" data-accordion="button" aria-controls="acc-panel-scientists-and-research" aria-expanded="false"> <span class="accordion__button__label"> Scientists and Research </span> </button> <div class="accordion__panel" id="acc-panel-scientists-and-research" data-accordion="panel" aria-labelledby="acc-button-scientists-and-research" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-scientific-research" data-accordion="button" aria-controls="acc-panel-scientific-research" aria-expanded="false"> <span class="accordion__button__label"> Scientific Research </span> </button> <div class="accordion__panel" id="acc-panel-scientific-research" data-accordion="panel" aria-labelledby="acc-button-scientific-research" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/scientists-and-research/58/collaborative-research-in-the-arctic-towards-understanding-climate-change/183">Collaborative Research in the Arctic Towards Understanding Climate Change</a></li> <li><a href="/en/library/scientists-and-research/58/from-stable-chromosomes-to-jumping-genes/184">From Stable Chromosomes to Jumping Genes</a></li> <li><a href="/en/library/scientists-and-research/58/an-elegant-experiment-to-test-the-process-of-dna-replication/187">An Elegant Experiment to Test the Process of DNA Replication</a></li> <li><a href="/en/library/scientists-and-research/58/the-founding-of-neuroscience/233">The Founding of Neuroscience</a></li> <li><a href="/en/library/scientists-and-research/58/tracking-endangered-jaguars-across-the-border/189">Tracking Endangered Jaguars across the Border</a></li> <li><a href="/en/library/scientists-and-research/58/atmospheric-chemistry-research-that-changed-global-policy/211">Atmospheric Chemistry Research that Changed Global Policy</a></li> <li><a href="/en/library/scientists-and-research/58/revolutionizing-medicine-with-monoclonal-antibodies/220">Revolutionizing Medicine with Monoclonal Antibodies</a></li> <li><a href="/en/library/scientists-and-research/58/uncovering-the-mysteries-of-chronic-mountain-sickness/238">Uncovering the Mysteries of Chronic Mountain Sickness</a></li> </ul> </div> <button class="accordion__button" id="acc-button-profiles-in-science" data-accordion="button" aria-controls="acc-panel-profiles-in-science" aria-expanded="false"> <span class="accordion__button__label"> Profiles in Science </span> </button> <div class="accordion__panel" id="acc-panel-profiles-in-science" data-accordion="panel" aria-labelledby="acc-button-profiles-in-science" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/scientists-and-research/58/luis-e.-miramontes/232">Luis E. Miramontes</a></li> <li><a href="/en/library/scientists-and-research/58/bernardo-houssay/237">Bernardo Houssay</a></li> <li><a href="/en/library/scientists-and-research/58/craig-lee/256">Craig Lee</a></li> <li><a href="/en/library/scientists-and-research/58/david-ho/241">David Ho</a></li> <li><a href="/en/library/scientists-and-research/58/louis-tompkins-wright/244">Louis Tompkins Wright</a></li> <li><a href="/en/library/scientists-and-research/58/carlos-j.-finlay/217">Carlos J. Finlay</a></li> <li><a href="/en/library/scientists-and-research/58/cecilia-payne/290">Cecilia Payne</a></li> <li><a href="/en/library/scientists-and-research/58/jazmin-scarlett/291">Jazmin Scarlett</a></li> <li><a href="/en/library/scientists-and-research/58/ramari-stewart/292">Ramari Stewart</a></li> <li><a href="/en/library/scientists-and-research/58/johnson-cerda/300">Johnson Cerda</a></li> <li><a href="/en/library/scientists-and-research/58/ellen-ochoa/201">Ellen Ochoa</a></li> <li><a href="/en/library/scientists-and-research/58/ruth-benerito/205">Ruth Benerito</a></li> <li><a href="/en/library/scientists-and-research/58/franklin-chang-d铆az/219">Franklin Chang D铆az</a></li> <li><a href="/en/library/scientists-and-research/58/percy-lavon-julian/221">Percy Lavon Julian</a></li> <li><a href="/en/library/scientists-and-research/58/luis-walter-alvarez/229">Luis Walter Alvarez</a></li> <li><a href="/en/library/scientists-and-research/58/france-anne-dominic-c贸rdova/230">France Anne-Dominic C贸rdova</a></li> </ul> </div> </div> </div> </div> </div> </li> <li>  <button class="button" data-toggle="dropdown">Chemistry </button> <div class="nav__dropdown box-shadow-1 padding-1"> <div class="accordion accordion--secondary font-size-sm"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-sub-button-atomic-theory-and-structure" data-accordion="button" aria-controls="acc-sub-panel-atomic-theory-and-structure" aria-expanded="false"> <span class="accordion__button__label"> Atomic Theory and Structure </span> </button> <div class="accordion__panel" id="acc-sub-panel-atomic-theory-and-structure" data-accordion="panel" aria-labelledby="acc-sub-button-atomic-theory-and-structure" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/chemistry/1/early-ideas-about-matter/49">Early Ideas about Matter</a></li> <li><a href="/en/library/chemistry/1/the-periodic-table-of-elements-i/52">The Periodic Table of Elements I</a></li> <li><a href="/en/library/chemistry/1/the-periodic-table-of-elements-ii/296">The Periodic Table of Elements II</a></li> <li><a href="/en/library/chemistry/1/the-periodic-table-of-elements-iii/297">The Periodic Table of Elements III</a></li> <li><a href="/en/library/chemistry/1/the-periodic-table-of-elements-iv/298">The Periodic Table of Elements IV</a></li> <li><a href="/en/library/chemistry/1/the-periodic-table-of-elements-v/299">The Periodic Table of Elements V</a></li> <li><a href="/en/library/chemistry/1/atomic-theory-i/50">Atomic Theory I</a></li> <li><a href="/en/library/chemistry/1/atomic-theory-ii/51">Atomic Theory II</a></li> <li><a href="/en/library/chemistry/1/atomic-theory-iii/223">Atomic Theory III</a></li> <li><a href="/en/library/chemistry/1/atomic-theory-iv/231">Atomic Theory IV</a></li> <li><a href="/en/library/chemistry/1/the-mole-and-atomic-mass/53">The Mole and Atomic Mass</a></li> </ul> </div> <button class="accordion__button" id="acc-sub-button-physical-states-and-properties" data-accordion="button" aria-controls="acc-sub-panel-physical-states-and-properties" aria-expanded="false"> <span class="accordion__button__label"> Physical States and Properties </span> </button> <div class="accordion__panel" id="acc-sub-panel-physical-states-and-properties" data-accordion="panel" aria-labelledby="acc-sub-button-physical-states-and-properties" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/chemistry/1/states-of-matter/120">States of Matter</a></li> <li><a href="/en/library/chemistry/1/substances/280">Substances</a></li> <li><a href="/en/library/chemistry/1/properties-of-solids/209">Properties of Solids</a></li> <li><a href="/en/library/chemistry/1/properties-of-liquids/222">Properties of Liquids</a></li> <li><a href="/en/library/chemistry/1/properties-of-gases/245">Properties of Gases</a></li> <li><a href="/en/library/chemistry/1/diffusion-i/216">Diffusion I</a></li> <li><a href="/en/library/chemistry/1/kinetic-molecular-theory/251">Kinetic-Molecular Theory</a></li> <li><a href="/en/library/chemistry/1/solutions/266">Solutions</a></li> <li><a href="/en/library/chemistry/1/water/267">Water</a></li> </ul> </div> <button class="accordion__button" id="acc-sub-button-chemical-relationships" data-accordion="button" aria-controls="acc-sub-panel-chemical-relationships" aria-expanded="false"> <span class="accordion__button__label"> Chemical Relationships </span> </button> <div class="accordion__panel" id="acc-sub-panel-chemical-relationships" data-accordion="panel" aria-labelledby="acc-sub-button-chemical-relationships" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/chemistry/1/chemical-bonding/55">Chemical Bonding</a></li> <li><a href="/en/library/chemistry/1/stoichiometry/270">Stoichiometry</a></li> <li><a href="/en/library/chemistry/1/chemical-equations/268">Chemical Equations</a></li> <li><a href="/en/library/chemistry/1/acids-and-bases-i/271">Acids and Bases I</a></li> <li><a href="/en/library/chemistry/1/acids-and-bases-ii/272">Acids and Bases II</a></li> </ul> </div> <button class="accordion__button" id="acc-sub-button-reactions-and-changes" data-accordion="button" aria-controls="acc-sub-panel-reactions-and-changes" aria-expanded="false"> <span class="accordion__button__label"> Reactions and Changes </span> </button> <div class="accordion__panel" id="acc-sub-panel-reactions-and-changes" data-accordion="panel" aria-labelledby="acc-sub-button-reactions-and-changes" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/chemistry/1/chemical-reactions/54">Chemical Reactions</a></li> <li><a href="/en/library/chemistry/1/chemical-reactions-ii/278">Chemical Reactions II</a></li> <li class="current">Nuclear Chemistry I</li> <li><a href="/en/library/chemistry/1/carbon-chemistry/60">Carbon Chemistry</a></li> </ul> </div> </div> </div> </div> </li> </ul> </nav>  <div id="theTop"></div> <main id="skip-header-content"> <div class="margin-bottom-5"> <article class="container wide module"> <header class="grid grid--sidebar-right module__header"> <div class="module__header__title"> <span class="subcategory"> <strong><em>Reactions and Changes</em></strong> </span> <h1>Nuclear Chemistry I: <sub><em>Radiation, half-life, and nuclear reactions</em></sub></h1> <p class="byline">by Judi Luepke, PhD.</p> <nav class="module__header__tabs"> <ul class="tabs-nav tabs-nav--horizontal library"> <li> <a href="/en/library/chemistry/1/nuclear-chemistry-i/284/reading" aria-current="page" >Reading</a> </li> <li> <a href="/en/library/chemistry/1/nuclear-chemistry-i/284/quiz">Quiz</a> </li> <li> <a href="/en/library/chemistry/1/nuclear-chemistry-i/284/resources">Teach with this</a> </li> </ul> </nav> </div> </header> <hr class="divider"/>   <div class="grid grid--sidebar-right grid--divider"> <div class="order-2 order-1--lg module__main"> <div class="narrow margin-x-auto margin-y-5"> <div class="accordion margin-bottom-5">  <button class="accordion__button" id="acc-button-key-concepts" data-accordion="button" aria-controls="acc-panel-key-concepts" aria-expanded="true" tabindex="0"> Did you know? </button> <div class="accordion__panel shown show" id="acc-panel-key-concepts" data-accordion="panel" aria-labelledby="acc-button-key-concepts" role="region"> <div class="accordion__panel__content"> <p>Did you know that radioisotopes emit particles and energy as background radiation in your everyday environment? The low levels are not harmful to you. But the first scientists to work with radiation placed themselves in harm鈥檚 way, leading to the development of radiation therapies that can save your life! Let鈥檚 find out.</p> </div> </div>  <button class="accordion__button" id="acc-button-table-of-contents" data-accordion="button" aria-controls="acc-panel-table-of-contents" aria-expanded="false" tabindex="0"> Key concepts </button> <div class="accordion__panel" id="acc-panel-table-of-contents" data-accordion="panel" aria-labelledby="acc-button-table-of-contents" role="region" aria-hidden="true"> <div class="accordion__panel__content"> <ul class="bulleted"> <li><p>The discovery of radiation and radioactive elements was a landmark event in science as it ushered in a series of experiments that would help us understand the structure of the atom and the nature of subatomic particles.</p></li> <li><p>Despite facing extraordinary bias and prejudice as a woman in science, Marie Curie made pivotal discoveries in this field.</p></li> <li><p>Radioisotopes, or forms of elements that have unstable atomic nuclei, undergo decay by releasing parts of their nucleus and energy to the environment. The three most common types of radioactive decay were discovered in the early 20th century and include alpha, beta, and gamma decay. </p></li> <li><p>Scientists have observed that radiation occurs randomly, though predictably. And the decay of a radioactive isotope can be described in terms of its half-life - a measure of the amount of time it takes for one-half of the amount of a radioactive element to decay. The half-life is a unique property of each radioactive element. </p></li> <li><p>Medical research has shown that radiation therapy is an effective method for treating some cancers and is now an accepted part of a doctor鈥檚 tools in treating cancer. </p></li> </ul> </div> </div>  <button class="accordion__button" id="acc-button-terms-you-should-know" data-accordion="button" aria-controls="acc-panel-terms-you-should-know" aria-expanded="false" tabindex="0"> Terms you should know </button> <div class="accordion__panel" id="acc-panel-terms-you-should-know" data-accordion="panel" aria-labelledby="acc-button-terms-you-should-know" role="region" aria-hidden="true"> <div class="accordion__panel__content"> <dl> <dt><a href="/en/glossary/view/radioactivity">Radioactivity </a></dt> <dd> The spontaneous emission of radiation, due to a nuclear reaction or direct emission from an unstable atomic nucleus. </dd> <dt><a href="/en/glossary/view/element">Element </a></dt> <dd> A substance composed of atoms with identical atomic number. </dd> <dt><a href="/en/glossary/view/particle">Particle </a></dt> <dd> A tiny piece of matter. </dd> <dt><a href="/en/glossary/view/nucleus">Nucleus </a></dt> <dd> A tiny, dense positively charged mass at the heart of an atom. </dd> <dt><a href="/en/glossary/view/atom">Atom </a></dt> <dd> The smallest unit of an element that retains the chemical properties of the element.</dd> </dl> </div> </div> </div> <hr class="border-color-dark" /> <section> <div class="container narrow"> <p>Have you ever known someone who has had cancer? Cancer is a disease that causes <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark> to grow uncontrollably and <mark class="term" data-term="spread" data-term-def="The variation within a dataset; the measure of how much individual values in a dataset differ from the mean, or average." data-term-url="/en/glossary/view/spread/8761">spread</mark> to other parts of the body and is very difficult to treat. It has been recorded throughout history, with ancient mummies even showing <mark class="term" data-term="evidence" data-term-def="Support for an idea, opinion, or hypothesis." data-term-url="/en/glossary/view/evidence/8243">evidence</mark> of cancer. Cancer patients and their families desperately search for <mark class="term" data-term="treatment" data-term-def="In science, a treatment refers to a method for fixing or manipulating an independent variable in the course of scientific research.&hellip;" data-term-url="/en/glossary/view/treatment/3799">treatments</mark> that will put the disease into remission.</p> <p>Often times, treatment plans include <mark class="term" data-term="radiation" data-term-def="Energy emitted as particles, waves, or rays." data-term-url="/en/glossary/view/radiation/8266">radiation</mark> therapy, as shown in Figure 1. Imagine being able to enjoy extra months and even years with a loved one because radiation made their cancer symptoms disappear! It is no wonder that people marveled at this particular use of radiation after its discovery.</p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox=""> <img src="/img/library/modules/mid284/Image/VLObject-12709-22100702103118.jpeg" alt="Figure 1: Radiation therapy for cancer." /> </button> <figcaption> <p><strong>Figure 1:</strong> Radiation therapy for cancer.</p> <span class="credit">image ©<a href="https://commons.wikimedia.org/wiki/File:Radiation_therapy_for_cancer.jpg"> CC BY-SA 4.0 Jakembradford</a> </span> </figcaption> </figure> </div> <p>In this module, you will learn about radioactive <mark class="term" data-term="isotope" data-term-def="Atoms of the same element with different numbers of neutrons in their atomic nucleus. Isotopes have the same chemical properties and&hellip;" data-term-url="/en/glossary/view/isotope/1516">isotopes</mark> and how they <mark class="term" data-term="decay" data-term-def="To break down; to decrease over time in size, amount, or force." data-term-url="/en/glossary/view/decay/8265">decay</mark> to give off <mark class="term" data-term="energy" data-term-def="An abstract property defined as the capacity to do work. The basic forms of energy include chemical, electrical, mechanical, nuclear, and&hellip;" data-term-url="/en/glossary/view/energy/1497">energy</mark> that can be used in <mark class="term" data-term="radiation" data-term-def="Energy emitted as particles, waves, or rays." data-term-url="/en/glossary/view/radiation/8266">radiation</mark> therapy. You learn what alpha, beta, and gamma radioactive decay are and how they can be represented by nuclear equation <mark class="term" data-term="model" data-term-def="A representation, pattern, or mathematical description that can help scientists replicate a system." data-term-url="/en/glossary/view/model/8236">models</mark>. Let’s get started by going back to the discovery of radium, a radioactive isotope.</p> <p><section id="toc_1" class=""> <h2>The discovery of <mark class="term" data-term="radiation" data-term-def="Energy emitted as particles, waves, or rays." data-term-url="/en/glossary/view/radiation/8266">radiation</mark> and radium</h2></p> <p>Radium is one of the earlier radioactive <mark class="term" data-term="element" data-term-def="One of fewer than 118 pure chemical substances. An element is a substance composed of atoms with identical atomic number." data-term-url="/en/glossary/view/element/1510">elements</mark> to be discovered, and it is still used today in the <mark class="term" data-term="treatment" data-term-def="In science, a treatment refers to a method for fixing or manipulating an independent variable in the course of scientific research.&hellip;" data-term-url="/en/glossary/view/treatment/3799">treatment</mark> of cancer. Radium was discovered by <mark class="term" data-term="Marie Curie" data-term-def="French-Polish physicist and chemist born in Warsaw (1867–1934). Curie was the Head of the Physics Laboratory at the Sorbonne. Working with&hellip;" data-term-url="/en/glossary/view/Curie%2C+Marie/4569">Marie Curie</mark>, arguably one of the most famous scientists in the world. Marie Curie was born Maria Sklodowska in Poland in 1867. Sklodowska grew up in poverty in Warsaw, Poland. At the time, scientists were exclusively men, and even admission into a university was reserved for men. So it was that although Sklodowska graduated first in her class from high school, she was banned from attending university in Poland. Not accepting that rejection as the final say in her education, Sklodowska attended a “Flying University” in Poland, so called because the university held classes secretly in changing locations, including in private homes, to avoid the restrictions that were in place at the time, such as those against women attending. Marie was totally committed to her education, in fact, a few years before she had made a pact with her sister Bronya - they would move to Paris and Marie would <mark class="term" data-term="work" data-term-def="A process that occurs when a force acts over a distance, as when an object is moved. Work equals the multiple&hellip;" data-term-url="/en/glossary/view/work/1502">work</mark> to help pay for Bronya’s education, and then Bronya would do the same for Marie. And so, in 1891, Marie moved to Paris to join her sister and attend the Sorbonne. Sklodowska continued to struggle in Paris, lacking in money, but working hard to prove herself as a scientist. By a chance encounter, she came to work in the lab of a young scientist named <mark class="term" data-term="Pierre Curie" data-term-def="French physicist born in Paris (1859-1906 CE). Pioneer in the fields of crystallography, magnetism, and piezoelectricity, he shared the 1903 Nobel&hellip;" data-term-url="/en/glossary/view/Curie%2C+Pierre/4757">Pierre Curie</mark>. Pierre and Marie would eventually marry and change the course of science with their groundbreaking <mark class="term" data-term="research" data-term-def="A study or an investigation." data-term-url="/en/glossary/view/research/8257">research</mark> into the newly discovered phenomenon of <mark class="term" data-term="radioactivity" data-term-def="The spontaneous emission of radiation, due to a nuclear reaction or direct emission from an unstable atomic nucleus. Radioactivity takes&hellip;" data-term-url="/en/glossary/view/radioactivity/5301">radioactivity</mark>.</p> <p>The Curies started a family together as both continued with their research. In the late 1890s Marie faced a milestone, she needed to choose a topic for her doctoral research, and no woman had yet been awarded a doctorate in science. Curie’s decision was influenced by two important discoveries. In 1895, the German physicist Wilhelm Roentgen discovered a strange type of <mark class="term" data-term="radiation" data-term-def="Energy emitted as particles, waves, or rays." data-term-url="/en/glossary/view/radiation/8266">radiation</mark> which were called <mark class="term" data-term="X-ray" data-term-def="A form of electromagnetic radiation with higher frequency and energy than any other electromagnetic radiation besides gamma rays. X-rays have various&hellip;" data-term-url="/en/glossary/view/X~ray/7573">X-rays</mark>, that could travel through <mark class="term" data-term="solid" data-term-def="A collection of atoms or molecules that are held together so that, under constant conditions, they maintain a defined shape and&hellip;" data-term-url="/en/glossary/view/solid/7571">solid</mark> objects and even yield images of peoples’ bones. And in 1896, Frenchman <mark class="term" data-term="Henri Becquerel" data-term-def="French physicist, born in Paris (1852-1908). Becquerel's most famous work is his study of uranium salts, which he discovered produced rays&hellip;" data-term-url="/en/glossary/view/Becquerel%2C+Henri/4485">Henri Becquerel</mark> made a unique, and accidental discovery. Becquerel placed uranium <mark class="term" data-term="salt" data-term-def="Generally, any ionic compound except those that contain hydroxide or hydrogen ions. Specifically, any compound other than water formed by&hellip;" data-term-url="/en/glossary/view/salt/1575">salts</mark> and photographic plates in a laboratory drawer overnight to use in an <mark class="term" data-term="experiment" data-term-def="A test or trial carried out under controlled conditions so that specific actions can be performed and the results can be observed." data-term-url="/en/glossary/view/experiment/8292">experiment</mark>. The next day, he was surprised to see that the plates, quite expensive and difficult to obtain at the time, looked as if they had been exposed to <mark class="term" data-term="light" data-term-def="A form of electromagnetic radiation. Visible light is that associated with stimulating the organs of sight, which for normal human&hellip;" data-term-url="/en/glossary/view/light/1498">light</mark>. The uranium salts had released <mark class="term" data-term="energy" data-term-def="An abstract property defined as the capacity to do work. The basic forms of energy include chemical, electrical, mechanical, nuclear, and&hellip;" data-term-url="/en/glossary/view/energy/1497">energy</mark> to change the photographic plates.</p> <p>Curie chose to study Becquerel’s “uranium rays” for her thesis and her work yielded important discoveries. Working in a small, damp storage room as a lab, Marie’s experiments led her to propose that the rays were a <mark class="term" data-term="property" data-term-def="A characteristic or attribute." data-term-url="/en/glossary/view/property/8555">property</mark> of the very <mark class="term" data-term="atom" data-term-def="The smallest unit of an element that retains the chemical properties of the element. Atoms can exist alone or in&hellip;" data-term-url="/en/glossary/view/atom/1509">atoms</mark> of uranium contained in the salts and she began testing other elements, eventually discovering that thorium also emitted these strange rays. Curie named the phenomenon “radioactivity,” based on the Latin name for rays.</p> <p>Pierre was so intrigued by Marie’s discovery that he soon joined her in her work, and the Curies sought to learn more about radioactivity. They separated pitchblende, a black uranium-containing ore, to remove uranium. To their surprise, the remaining ore was still radioactive even with the uranium removed! They worked laboriously to separate a new element, polonium (named for Marie’s home country of Poland), from the remaining ore. But the remaining ore was still radioactive! They removed a second new element that was one million times more radioactive than uranium. They named this element radium, again using the Latin term for “ray.”</p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox=""> <img src="/img/library/modules/mid284/Image/VLObject-12713-22100702103446.jpeg" alt="Figure 2: Marie Curie working in the laboratory." /> </button> <figcaption> <p><strong>Figure 2:</strong> Marie Curie working in the laboratory.</p> <span class="credit">image ©<a href="https://commons.wikimedia.org/wiki/File:Marie-Curie.jpg"> CC BY-SA 4.0 VictoriaKC</a> </span> </figcaption> </figure> </div> <p>Separating <mark class="term" data-term="element" data-term-def="One of fewer than 118 pure chemical substances. An element is a substance composed of atoms with identical atomic number." data-term-url="/en/glossary/view/element/1510">elements</mark> from pitchblende was very hard <mark class="term" data-term="work" data-term-def="A process that occurs when a force acts over a distance, as when an object is moved. Work equals the multiple&hellip;" data-term-url="/en/glossary/view/work/1502">work</mark>. Ten tons of pitchblende yielded just one milligram of radium. Unknowingly, in the <mark class="term" data-term="process" data-term-def="Method, procedure; series of actions or steps." data-term-url="/en/glossary/view/process/8256">process</mark>, the Curies were exposed to high doses of <mark class="term" data-term="radiation" data-term-def="Energy emitted as particles, waves, or rays." data-term-url="/en/glossary/view/radiation/8266">radiation</mark> and suffered from radiation sickness as they worked with the most radioactive natural element ever discovered. They were chronically weak, coughed, and had regular burns on their skin. Their sacrifices in the lab to discover elements and learn more about <mark class="term" data-term="radioactivity" data-term-def="The spontaneous emission of radiation, due to a nuclear reaction or direct emission from an unstable atomic nucleus. Radioactivity takes&hellip;" data-term-url="/en/glossary/view/radioactivity/5301">radioactivity</mark> eventually led to them, and <mark class="term" data-term="Henri Becquerel" data-term-def="French physicist, born in Paris (1852-1908). Becquerel's most famous work is his study of uranium salts, which he discovered produced rays&hellip;" data-term-url="/en/glossary/view/Becquerel%2C+Henri/4485">Henri Becquerel</mark>, being awarded a <mark class="term" data-term="Nobel Prize" data-term-def="Awards made annually, beginning in 1901, from funds originally established by Alfred B. Nobel for outstanding achievement in physics, chemistry, medicine&hellip;" data-term-url="/en/glossary/view/Nobel+Prize/3843">Nobel Prize</mark> in physics in 1903 - the first ever Nobel Prize awarded to a woman - for their discovery of spontaneous radiation. In 1911, <mark class="term" data-term="Marie Curie" data-term-def="French-Polish physicist and chemist born in Warsaw (1867–1934). Curie was the Head of the Physics Laboratory at the Sorbonne. Working with&hellip;" data-term-url="/en/glossary/view/Curie%2C+Marie/4569">Marie Curie</mark> was actually awarded a second Nobel Prize in chemistry for her work with radioactivity, the first person, and still one of only two people, who have ever won two Nobel prizes in science.</p> <div class="comprehension-checkpoint margin-y-4"> <h6 class="comprehension-checkpoint__header"> <span> <span class="icon icon-question"></span> </span> Comprehension Checkpoint </h6> <form class="" name="cc12715"> <div class="form-entry"> <div class="form-entry__field"> <span class="form-entry__field__label">Which elements did the Curies discover?</span> <div class="form-entry__option"> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-12715-0-option-a" name="quiz-option-12715" type="radio" value="uranium and radium" > <span class="option__label"> <span class="screen-reader-only">a.</span> uranium and radium </span> </label> <span class="quiz__response" id="response-12715-0"> <strong>Incorrect.</strong> </span> </div> <div class="form-entry__option__radio" data-answer="correct"> <label> <input id="q1-12715-1-option-b" name="quiz-option-12715" type="radio" value="radium and polonium" > <span class="option__label"> <span class="screen-reader-only">b.</span> radium and polonium </span> </label> <span class="quiz__response" id="response-12715-1"> <strong>Correct!</strong> </span> </div> </div> </div> </div> </form> </div> </section> <section id="toc_2"> <h2>Radioactivity</h2><p>So what exactly is “radioactivity”? <mark class="term" data-term="radioactivity" data-term-def="The spontaneous emission of radiation, due to a nuclear reaction or direct emission from an unstable atomic nucleus. Radioactivity takes&hellip;" data-term-url="/en/glossary/view/radioactivity/5301">Radioactivity</mark> is the spontaneous release of <mark class="term" data-term="energy" data-term-def="An abstract property defined as the capacity to do work. The basic forms of energy include chemical, electrical, mechanical, nuclear, and&hellip;" data-term-url="/en/glossary/view/energy/1497">energy</mark> from certain <mark class="term" data-term="atom" data-term-def="The smallest unit of an element that retains the chemical properties of the element. Atoms can exist alone or in&hellip;" data-term-url="/en/glossary/view/atom/1509">atoms</mark>. It is what Becquerel observed when his photographic plates became exposed and darkened. And it is the same energy that the Curies could not see, but that made them ill and burned their hands. So how do you study something that you can’t see? That was a challenge that faced scientists searching to learn more about the energy released from these processes.</p> <p>One of the first pieces of <mark class="term" data-term="evidence" data-term-def="Support for an idea, opinion, or hypothesis." data-term-url="/en/glossary/view/evidence/8243">evidence</mark> that helped scientists uncover the secrets of <mark class="term" data-term="radiation" data-term-def="Energy emitted as particles, waves, or rays." data-term-url="/en/glossary/view/radiation/8266">radiation</mark> came from <mark class="term" data-term="Ernest Rutherford" data-term-def="New Zealand-English physicist born in Nelson, New Zealand (1871-1937). Rutherford classified radiation into three types: alpha, beta, and gamma ray. In&hellip;" data-term-url="/en/glossary/view/Rutherford%2C+Ernest/4520">Ernest Rutherford</mark>, a Cambridge University physicist born in New Zealand and who later became famous for his <mark class="term" data-term="work" data-term-def="A process that occurs when a force acts over a distance, as when an object is moved. Work equals the multiple&hellip;" data-term-url="/en/glossary/view/work/1502">work</mark> uncovering the structure of the atom (see our <a href="https://www.visionlearning.com/en/library/Chemistry/1/Atomic-Theory-I/50">Atomic <mark class="term" data-term="theory" data-term-def="A scientific theory is an explanation inferred from multiple lines of evidence for some broad aspect of the natural world and&hellip;" data-term-url="/en/glossary/view/theory/4854">Theory</mark> I</a> module for more information on these later <mark class="term" data-term="experiment" data-term-def="A test or trial carried out under controlled conditions so that specific actions can be performed and the results can be observed." data-term-url="/en/glossary/view/experiment/8292">experiments</mark> of Rutherford’s). For his graduate work in 1898, Rutherford designed a set of simple experiments to study the mysterious rays emanating from uranium. He placed an increasing number of aluminum foil sheets between a uranium source and a detector. Rutherford observed that some of the radioactivity disappeared if he placed just one thin sheet of foil in front of the detector. However, some of the radiation traveled through and could still be seen by the detector. Rutherford correctly theorized that there were at least two types of radioactive <mark class="term" data-term="particle" data-term-def="A tiny piece of matter." data-term-url="/en/glossary/view/particle/8259">particles</mark> coming from the uranium source. The first type, which was blocked by one thin sheet of foil, he called alpha radiation. And the second type, he called beta radiation. Rutherford repeated the experiment many times with different radioactive sources and different metallic foils and he added in electromagnets to the set up to see if either of the particles he had discovered were charged. He observed that alpha rays were positively charged particles and beta rays were negatively charged particles.</p> <p>Paul Villard, a French chemist, took Rutherford’s work further in 1900. He used a lead screen to eliminate the alpha rays, and a magnetic field to eliminate the beta rays. And yet Villard still detected radiation. This radiation was powerful enough to travel through lead, and had no <mark class="term" data-term="charge" data-term-def="A quantity of electricity." data-term-url="/en/glossary/view/charge/8258">charge</mark> as it was not attracted or repelled by the magnets. Rutherford confirmed this discovery and eventually named this third type of radiation “gamma rays.”</p> <p>These experiments began to uncover the properties of radiation, but they gave little information about what caused radioactivity. At the time of its discovery, no one knew. Many scientists believed that radiation was energy that atoms had previously absorbed and which was being reemitted. This <mark class="term" data-term="hypothesis" data-term-def="From the Greek word <em>hypothesis</em> meaning assumption or the basis of an argument, a hypothesis is a proposal intended to explain&hellip;" data-term-url="/en/glossary/view/hypothesis/3727">hypothesis</mark> was later proved false, and Rutherford and English radiochemist <mark class="term" data-term="Frederick Soddy" data-term-def="British physicist born in Eastbourne, Sussex (1877-1956). He studied radioactivity with Ernest Rutherford, jointly concluding that radioactivity consisted of atomic disintegration&hellip;" data-term-url="/en/glossary/view/Soddy%2C+Frederick/4486">Frederick Soddy</mark> would go on to find the correct answer in 1901. Rutherford and Soddy’s relationship began not as a result of collaboration, but as a result of conflict. Rutherford had proposed that radiation was not previously absorbed energy, but was caused by the break up of atoms. Soddy did not believe this to be true, and actually debated Rutherford on the idea, motivating them to work together. Rutherford and Soddy began working with the radioactive <mark class="term" data-term="element" data-term-def="One of fewer than 118 pure chemical substances. An element is a substance composed of atoms with identical atomic number." data-term-url="/en/glossary/view/element/1510">element</mark> thorium. They observed that when thorium emitted radiation, a <mark class="term" data-term="gas" data-term-def="The state of matter characterized by its non-condensed nature and ability to flow. Unlike liquids, molecules within a gas remain far&hellip;" data-term-url="/en/glossary/view/gas/8725">gas</mark> was released. They collected and studied this gas and realized that it consisted of something entirely different from thorium, not a new chemical <mark class="term" data-term="compound" data-term-def="A material formed by the chemical combination of elements in defined proportions. Compounds can be chemically decomposed into simpler substances." data-term-url="/en/glossary/view/compound/1517">compound</mark>, but an entirely new element - the element radon, which had fewer subatomic particles than thorium. Rutherford and Soddy correctly theorized that radioactive particles were actually part of the <mark class="term" data-term="parent" data-term-def="The material or source from which something is derived." data-term-url="/en/glossary/view/parent/1618">parent</mark> element being released, and when these particles left the original element, it transformed into another element, releasing energy in the <mark class="term" data-term="process" data-term-def="Method, procedure; series of actions or steps." data-term-url="/en/glossary/view/process/8256">process</mark>. This “theory of atomic disintegration” was controversial at the time. But Rutherford and Soddy’s careful experiments and abundant <mark class="term" data-term="data" data-term-def="(plural form of <b>datum</b>) A collection of pieces of information, generally taking the form of numbers, text, bits, or facts, that&hellip;" data-term-url="/en/glossary/view/data/3729">data</mark> eventually convinced others of the process.</p> <p>Radioactive elements are unstable and transform into other elements. While scientists started to piece this together at the turn of the 20th century, the discovery of the atomic <mark class="term" data-term="nucleus" data-term-def="1. [Atomic] A tiny, dense positively charged mass at the heart of an atom. The nucleus is composed of protons and&hellip;" data-term-url="/en/glossary/view/nucleus/1526">nucleus</mark> in 1911 and the <mark class="term" data-term="observation" data-term-def="1. The act of noticing something. 2. A record of that which has been noticed." data-term-url="/en/glossary/view/observation/8255">observation</mark> of <mark class="term" data-term="proton" data-term-def="A subatomic (ß link to atom) particle with a positive charge of 1.60 × 10<sup>-19</sup> coulombs and a mass of 1.672&hellip;" data-term-url="/en/glossary/view/proton/854">protons</mark> in 1919, both by Rutherford, helped scientists better understand radioactivity and its different forms.</p> <div class="comprehension-checkpoint margin-y-4"> <h6 class="comprehension-checkpoint__header"> <span> <span class="icon icon-question"></span> </span> Comprehension Checkpoint </h6> <form class="" name="cc12718"> <div class="form-entry"> <div class="form-entry__field"> <span class="form-entry__field__label">What may be spontaneously released when radioactivity is observed?</span> <div class="form-entry__option"> <div class="form-entry__option__radio" data-answer="correct"> <label> <input id="q1-12718-0-option-a" name="quiz-option-12718" type="radio" value="energy" > <span class="option__label"> <span class="screen-reader-only">a.</span> energy </span> </label> <span class="quiz__response" id="response-12718-0"> <strong>Correct!</strong> </span> </div> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-12718-1-option-b" name="quiz-option-12718" type="radio" value="atoms" > <span class="option__label"> <span class="screen-reader-only">b.</span> atoms </span> </label> <span class="quiz__response" id="response-12718-1"> <strong>Incorrect.</strong> </span> </div> </div> </div> </div> </form> </div> </section> <section id="toc_3"> <h2>Radioactive isotopes</h2><p>Over the first few decades of the 20th century, a view of atomic structure had appeared from the many <mark class="term" data-term="experiment" data-term-def="A test or trial carried out under controlled conditions so that specific actions can be performed and the results can be observed." data-term-url="/en/glossary/view/experiment/8292">experiments</mark> that were conducted that helped scientists understand the <mark class="term" data-term="atom" data-term-def="The smallest unit of an element that retains the chemical properties of the element. Atoms can exist alone or in&hellip;" data-term-url="/en/glossary/view/atom/1509">atom</mark> and <mark class="term" data-term="radiation" data-term-def="Energy emitted as particles, waves, or rays." data-term-url="/en/glossary/view/radiation/8266">radiation</mark>. Rutherford’s experiments had led to a realization that atoms had small <mark class="term" data-term="dense" data-term-def="Compact, packed close together; having a high mass in relation to volume." data-term-url="/en/glossary/view/dense/8273">dense</mark> nuclei that contained the atom’s <mark class="term" data-term="proton" data-term-def="A subatomic (ß link to atom) particle with a positive charge of 1.60 × 10<sup>-19</sup> coulombs and a mass of 1.672&hellip;" data-term-url="/en/glossary/view/proton/854">protons</mark>, and that <mark class="term" data-term="electron" data-term-def="A subatomic particle with a negative charge of 1.60 × 10<sup>-19</sup> coulombs and a mass of 9.11 × 10<sup>-31</sup> kg. Electrons&hellip;" data-term-url="/en/glossary/view/electron/852">electrons</mark> resided outside of the <mark class="term" data-term="nucleus" data-term-def="1. [Atomic] A tiny, dense positively charged mass at the heart of an atom. The nucleus is composed of protons and&hellip;" data-term-url="/en/glossary/view/nucleus/1526">nucleus</mark> of the atom. Scientists also understood that radiation was caused by part of the nucleus being ejected from the atom. But some things still did not add up. Experiments with <mark class="term" data-term="alpha particle" data-term-def="A type of particle that is ejected from radioactive nuclei. Alpha particles consist of two protons and two neutrons and&hellip;" data-term-url="/en/glossary/view/alpha+particle/1525">alpha particles</mark>, which were now known to contain protons, suggested that they were too heavy to only contain protons. And there was something wrong with the masses of atoms. By this time scientists were able to measure both the <mark class="term" data-term="charge" data-term-def="A quantity of electricity." data-term-url="/en/glossary/view/charge/8258">charge</mark> and <mark class="term" data-term="mass" data-term-def="A fundamental property of matter which is a numerical measure of the inertia of an object or the amount of matter&hellip;" data-term-url="/en/glossary/view/mass/3417">mass</mark> of atoms, and charge increased in distinct whole number <mark class="term" data-term="ratio" data-term-def="The relationship between two or more quantities; relative amounts of two or more values expressed as a proportion." data-term-url="/en/glossary/view/ratio/8556">ratios</mark> - but mass did not. If one atom had twice as many protons and electrons as another, why was its mass not also double?</p> <p>A discovery in 1932 by a British scientist, <mark class="term" data-term="James Chadwick" data-term-def="English physicist born in Bollington, Cheshire (1891-1974). Chadwick worked with Ernest Rutherford on the disintegration of atoms by bombarding them with&hellip;" data-term-url="/en/glossary/view/Chadwick%2C+James/4484">James Chadwick</mark>, helped answer these questions and shed <mark class="term" data-term="light" data-term-def="A form of electromagnetic radiation. Visible light is that associated with stimulating the organs of sight, which for normal human&hellip;" data-term-url="/en/glossary/view/light/1498">light</mark> on the phenomenon of <mark class="term" data-term="radioactivity" data-term-def="The spontaneous emission of radiation, due to a nuclear reaction or direct emission from an unstable atomic nucleus. Radioactivity takes&hellip;" data-term-url="/en/glossary/view/radioactivity/5301">radioactivity</mark> and atomic structure. Fittingly, Chadwick made this discovery by using radiation itself. Chadwick bombarded beryllium atoms with alpha <mark class="term" data-term="particle" data-term-def="A tiny piece of matter." data-term-url="/en/glossary/view/particle/8259">particles</mark>, and observed a strange radiation being emitted. This radiation consisted of a small particle, but had no charge. Chadwick had discovered the existence of the <mark class="term" data-term="neutron" data-term-def="A sub-atomic particle with no charge and a mass of 1.675 × 10<sup>-27</sup> kg. Neutrons are found in the nucleus&hellip;" data-term-url="/en/glossary/view/neutron/1520">neutron</mark> in the nucleus. The neutron is a <mark class="term" data-term="neutral" data-term-def="Generally defined as neither one thing nor another. 1. Electrically neutral refers to having no net electrical charge, usually achieved&hellip;" data-term-url="/en/glossary/view/neutral/855">neutral</mark> particle with a mass about equal to that of a proton. The discovery helped explain a lot. The “heavy” mass of the alpha particle could be explained by the existence of the neutron, in fact two of them, in each alpha particle. And the ratio of mass to charge in atoms could now be explained. The neutron also explained another <mark class="term" data-term="observation" data-term-def="1. The act of noticing something. 2. A record of that which has been noticed." data-term-url="/en/glossary/view/observation/8255">observation</mark> by <mark class="term" data-term="Frederick Soddy" data-term-def="British physicist born in Eastbourne, Sussex (1877-1956). He studied radioactivity with Ernest Rutherford, jointly concluding that radioactivity consisted of atomic disintegration&hellip;" data-term-url="/en/glossary/view/Soddy%2C+Frederick/4486">Frederick Soddy</mark>. Soddy had continued studying the breakdown, or <mark class="term" data-term="decay" data-term-def="To break down; to decrease over time in size, amount, or force." data-term-url="/en/glossary/view/decay/8265">decay</mark>, of radioactive <mark class="term" data-term="element" data-term-def="One of fewer than 118 pure chemical substances. An element is a substance composed of atoms with identical atomic number." data-term-url="/en/glossary/view/element/1510">elements</mark>, and had found that some elements had more than one <mark class="term" data-term="atomic mass" data-term-def="The average mass of an atom of an element, usually expressed in atomic mass units. The term is often used interchangeably&hellip;" data-term-url="/en/glossary/view/atomic+mass/1513">atomic mass</mark>. Chadwick’s discovery explained why - the nuclei of different forms of the element had different numbers of neutrons but the same number of protons as other forms. Because the different forms had the same number of protons, their chemical properties and location on the periodic table was the same. And so a family friend of Soddy, Dr. Margaret Todd, suggested he call the forms of elements with different atomic masses “isotopes” meaning “same place” in Greek.</p> <p>Isotopes are atoms of the same element with different numbers of neutrons. For example, 99% of all carbon exists as carbon with an atomic mass of 12. Atoms of this <mark class="term" data-term="isotope" data-term-def="Atoms of the same element with different numbers of neutrons in their atomic nucleus. Isotopes have the same chemical properties and&hellip;" data-term-url="/en/glossary/view/isotope/1516">isotope</mark> of carbon contain 6 protons and 6 neutrons, which combine to give it a mass of 12. However, a very small percentage of carbon has an atomic mass of 14. Since this is still carbon, it has to have 6 protons, so what differs is that this isotope contains 8 neutrons. Isotopes are indicated by writing the element’s symbol followed by a dash and the mass. In this case, C-12 is the common isotope and C-14 is the less common isotope. C-14 is also unstable, which <mark class="term" data-term="mean" data-term-def="In statistics, mean commonly refers to the arithmetic mean, also called the average, which is one measure of the mid-point of&hellip;" data-term-url="/en/glossary/view/mean/4221">means</mark> it undergoes radioactive decay, which we will learn more about in just a bit.</p> <p>Another way to indicate isotopes is by writing them in isotopic notation. Figure 3 is a <mark class="term" data-term="model" data-term-def="A representation, pattern, or mathematical description that can help scientists replicate a system." data-term-url="/en/glossary/view/model/8236">model</mark> of the notation. The symbol of the element is written with a superscript number and a subscript number to the left of the symbol. The superscript number gives the atomic mass; the subscript number gives the <mark class="term" data-term="atomic number" data-term-def="The number of protons in an atomic nucleus." data-term-url="/en/glossary/view/atomic+number/1512">atomic number</mark>. Figure 3 shows what this model looks like.</p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox=""> <img src="/img/library/modules/mid284/Image/VLObject-12721-22100702104117.png" alt="Figure 3: Isotopic notation model for isotopes." /> </button> <figcaption> <p><strong>Figure 3:</strong> Isotopic notation model for isotopes.</p> <span class="credit">image ©Visionlearning</span> </figcaption> </figure> </div> <p>So, for carbon, its two forms would be written as:<div class="figure"><figure> $$\ce{^12_6C} \text{ and } \ce{^14_6C}$$ </figure></div></p><p>Some <mark class="term" data-term="isotope" data-term-def="Atoms of the same element with different numbers of neutrons in their atomic nucleus. Isotopes have the same chemical properties and&hellip;" data-term-url="/en/glossary/view/isotope/1516">isotopes</mark> of <mark class="term" data-term="element" data-term-def="One of fewer than 118 pure chemical substances. An element is a substance composed of atoms with identical atomic number." data-term-url="/en/glossary/view/element/1510">elements</mark> are unstable and <mark class="term" data-term="decay" data-term-def="To break down; to decrease over time in size, amount, or force." data-term-url="/en/glossary/view/decay/8265">decay</mark> to become smaller, more stable <mark class="term" data-term="atom" data-term-def="The smallest unit of an element that retains the chemical properties of the element. Atoms can exist alone or in&hellip;" data-term-url="/en/glossary/view/atom/1509">atoms</mark>, releasing <mark class="term" data-term="radiation" data-term-def="Energy emitted as particles, waves, or rays." data-term-url="/en/glossary/view/radiation/8266">radiation</mark> in the <mark class="term" data-term="process" data-term-def="Method, procedure; series of actions or steps." data-term-url="/en/glossary/view/process/8256">process</mark>. These are called “radioisotopes.” For example, carbon-12 is the stable isotope of the element, and C-14 is a radioisotope of carbon.</p> <div class="comprehension-checkpoint margin-y-4"> <h6 class="comprehension-checkpoint__header"> <span> <span class="icon icon-question"></span> </span> Comprehension Checkpoint </h6> <form class="" name="cc13574"> <div class="form-entry"> <div class="form-entry__field"> <span class="form-entry__field__label">What differs between isotopes?</span> <div class="form-entry__option"> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-13574-0-option-a" name="quiz-option-13574" type="radio" value="Number of protons" > <span class="option__label"> <span class="screen-reader-only">a.</span> Number of protons </span> </label> <span class="quiz__response" id="response-13574-0"> <strong>Incorrect.</strong> </span> </div> <div class="form-entry__option__radio" data-answer="correct"> <label> <input id="q1-13574-1-option-b" name="quiz-option-13574" type="radio" value="Number of neutrons" > <span class="option__label"> <span class="screen-reader-only">b.</span> Number of neutrons </span> </label> <span class="quiz__response" id="response-13574-1"> <strong>Correct!</strong> </span> </div> </div> </div> </div> </form> </div> </section> <section id="toc_4"> <h2>Types of radioactive decay</h2><p>So let’s take a closer look at the types of radioactive <mark class="term" data-term="decay" data-term-def="To break down; to decrease over time in size, amount, or force." data-term-url="/en/glossary/view/decay/8265">decay</mark> that can occur in <mark class="term" data-term="radioisotopes" data-term-def="Forms of elements that have unstable atomic nuclei and undergo decay by releasing parts of their nucleus and energy to the environment." data-term-url="/en/glossary/view/radioisotopes/13607">radioisotopes</mark>. Remember that these were identified by Rutherford and Villard, as discussed earlier in this module. The types of radioactive decay still bear the names given to them by these scientists.</p> <p>“Alpha decay” is the loss of an alpha (α) <mark class="term" data-term="particle" data-term-def="A tiny piece of matter." data-term-url="/en/glossary/view/particle/8259">particle</mark>. An <mark class="term" data-term="alpha particle" data-term-def="A type of particle that is ejected from radioactive nuclei. Alpha particles consist of two protons and two neutrons and&hellip;" data-term-url="/en/glossary/view/alpha+particle/1525">alpha particle</mark> is the same as a helium <mark class="term" data-term="nucleus" data-term-def="1. [Atomic] A tiny, dense positively charged mass at the heart of an atom. The nucleus is composed of protons and&hellip;" data-term-url="/en/glossary/view/nucleus/1526">nucleus</mark> in that it contains two <mark class="term" data-term="proton" data-term-def="A subatomic (ß link to atom) particle with a positive charge of 1.60 × 10<sup>-19</sup> coulombs and a mass of 1.672&hellip;" data-term-url="/en/glossary/view/proton/854">protons</mark> and two <mark class="term" data-term="neutron" data-term-def="A sub-atomic particle with no charge and a mass of 1.675 × 10<sup>-27</sup> kg. Neutrons are found in the nucleus&hellip;" data-term-url="/en/glossary/view/neutron/1520">neutrons</mark>. It is represented as $ \ce{^4_2He} $. Remember that the superscript “4” represents the <mark class="term" data-term="atomic mass" data-term-def="The average mass of an atom of an element, usually expressed in atomic mass units. The term is often used interchangeably&hellip;" data-term-url="/en/glossary/view/atomic+mass/1513">atomic mass</mark> of the particle, and the subscript “2” represents the <mark class="term" data-term="atomic number" data-term-def="The number of protons in an atomic nucleus." data-term-url="/en/glossary/view/atomic+number/1512">atomic number</mark>. Since this particle has two protons and no <mark class="term" data-term="electron" data-term-def="A subatomic particle with a negative charge of 1.60 × 10<sup>-19</sup> coulombs and a mass of 9.11 × 10<sup>-31</sup> kg. Electrons&hellip;" data-term-url="/en/glossary/view/electron/852">electrons</mark>, it has a <mark class="term" data-term="charge" data-term-def="A quantity of electricity." data-term-url="/en/glossary/view/charge/8258">charge</mark> of +2. The loss of an alpha particle can be represented or modeled with a nuclear equation. For example, Equation 1 gives the nuclear equation <mark class="term" data-term="model" data-term-def="A representation, pattern, or mathematical description that can help scientists replicate a system." data-term-url="/en/glossary/view/model/8236">model</mark> for the alpha decay of radium-226 to become radon-222, a more stable radioisotope. Figure 4 provides a diagram of the decay <mark class="term" data-term="process" data-term-def="Method, procedure; series of actions or steps." data-term-url="/en/glossary/view/process/8256">process</mark>.</p><div class="figure"><figure>$$\ce{^236_88Ra} \rightarrow \ce{^222_86Rn} + \ce{^4_2\alpha}$$ <figcaption><strong>Equation 1</strong></figcaption> </figure></div> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox=""> <img src="/img/library/modules/mid284/Image/VLObject13578-24082011083429.jpg" alt="Figure 4: A radium-226 nucleus undergoes alpha decay to radon-222 and emits an alpha particle. " /> </button> <figcaption> <p><strong>Figure 4:</strong> A radium-226 nucleus undergoes alpha decay to radon-222 and emits an alpha particle. </p> <span class="credit">image ©<a href="https://commons.wikimedia.org/wiki/File:Alpha-decay.png"> Public Domain</a> </span> </figcaption> </figure> </div> <p>Notice a few things about Equation 1. First, as originally observed by Soddy, when radium undergoes radioactive <mark class="term" data-term="decay" data-term-def="To break down; to decrease over time in size, amount, or force." data-term-url="/en/glossary/view/decay/8265">decay</mark>, it turns into a smaller <mark class="term" data-term="element" data-term-def="One of fewer than 118 pure chemical substances. An element is a substance composed of atoms with identical atomic number." data-term-url="/en/glossary/view/element/1510">element</mark>. Second, both <mark class="term" data-term="atomic mass" data-term-def="The average mass of an atom of an element, usually expressed in atomic mass units. The term is often used interchangeably&hellip;" data-term-url="/en/glossary/view/atomic+mass/1513">atomic mass</mark> and <mark class="term" data-term="atomic number" data-term-def="The number of protons in an atomic nucleus." data-term-url="/en/glossary/view/atomic+number/1512">atomic number</mark> are conserved on the <mark class="term" data-term="reactant" data-term-def="The initial material that participates in a chemical reaction. Written on the left side of a chemical equation. Compare&hellip;" data-term-url="/en/glossary/view/reactant/1568">reactant</mark> side and the <mark class="term" data-term="product" data-term-def="The material that is formed as a result of a chemical reaction. Written on the right side of a chemical equation.&hellip;" data-term-url="/en/glossary/view/product/1569">product</mark> side. Meaning, the atomic <mark class="term" data-term="mass" data-term-def="A fundamental property of matter which is a numerical measure of the inertia of an object or the amount of matter&hellip;" data-term-url="/en/glossary/view/mass/3417">mass</mark> on the reactant side, 226, equals the sum of masses on the reactant side (222 + 4 = 226). And this is true for the atomic number as well. The mass on the left, 88, equals the sum on the right (86 + 2). <mark class="term" data-term="particle" data-term-def="A tiny piece of matter." data-term-url="/en/glossary/view/particle/8259">Particles</mark> are not lost (or gained) during this decay. The number of particles leaving radium as an <mark class="term" data-term="alpha particle" data-term-def="A type of particle that is ejected from radioactive nuclei. Alpha particles consist of two protons and two neutrons and&hellip;" data-term-url="/en/glossary/view/alpha+particle/1525">alpha particle</mark> equals the number of fewer particles that the resulting radon <mark class="term" data-term="atom" data-term-def="The smallest unit of an element that retains the chemical properties of the element. Atoms can exist alone or in&hellip;" data-term-url="/en/glossary/view/atom/1509">atom</mark> contains.</p> <p>“Beta decay” is the loss of a beta (β) particle. A <mark class="term" data-term="beta particle" data-term-def="An electron released by some radioisotopes during radioactive decay." data-term-url="/en/glossary/view/beta+particle/13608">beta particle</mark> turns out to be an <mark class="term" data-term="electron" data-term-def="A subatomic particle with a negative charge of 1.60 × 10<sup>-19</sup> coulombs and a mass of 9.11 × 10<sup>-31</sup> kg. Electrons&hellip;" data-term-url="/en/glossary/view/electron/852">electron</mark> or $\ce{^0_-1e}$ with a <mark class="term" data-term="charge" data-term-def="A quantity of electricity." data-term-url="/en/glossary/view/charge/8258">charge</mark> of -1. The loss of a beta particle can also be represented with a nuclear equation. Equation 2 gives the nuclear equation for the beta decay of lead-214 to become bismuth-214, a more stable radioisotope.</p><div class="figure"><figure> <p style="text-align: center;">$$\ce{^214_82Pb} \rightarrow \ce{^214_83Bi} + \ce{^0_-1e}$$</p> <figcaption><strong>Equation 2</strong></figcaption> </figure></div><p>Take a close look at equation 2. What do you notice? The <mark class="term" data-term="atomic mass" data-term-def="The average mass of an atom of an element, usually expressed in atomic mass units. The term is often used interchangeably&hellip;" data-term-url="/en/glossary/view/atomic+mass/1513">atomic mass</mark> of the starting lead <mark class="term" data-term="atom" data-term-def="The smallest unit of an element that retains the chemical properties of the element. Atoms can exist alone or in&hellip;" data-term-url="/en/glossary/view/atom/1509">atom</mark> and the resulting bismuth atom are the same at 214. But what about the atomic number? It actually increases—how can this be? Well, the <mark class="term" data-term="electron" data-term-def="A subatomic particle with a negative charge of 1.60 × 10<sup>-19</sup> coulombs and a mass of 9.11 × 10<sup>-31</sup> kg. Electrons&hellip;" data-term-url="/en/glossary/view/electron/852">electron</mark> lost from lead is not released from the electron shells—it is ejected from the <mark class="term" data-term="nucleus" data-term-def="1. [Atomic] A tiny, dense positively charged mass at the heart of an atom. The nucleus is composed of protons and&hellip;" data-term-url="/en/glossary/view/nucleus/1526">nucleus</mark>. In beta <mark class="term" data-term="decay" data-term-def="To break down; to decrease over time in size, amount, or force." data-term-url="/en/glossary/view/decay/8265">decay</mark>, a <mark class="term" data-term="neutron" data-term-def="A sub-atomic particle with no charge and a mass of 1.675 × 10<sup>-27</sup> kg. Neutrons are found in the nucleus&hellip;" data-term-url="/en/glossary/view/neutron/1520">neutron</mark> itself is unstable and decays by releasing both an electron and a <mark class="term" data-term="proton" data-term-def="A subatomic (ß link to atom) particle with a positive charge of 1.60 × 10<sup>-19</sup> coulombs and a mass of 1.672&hellip;" data-term-url="/en/glossary/view/proton/854">proton</mark>. The proton is retained in the nucleus, and thus the <mark class="term" data-term="atomic number" data-term-def="The number of protons in an atomic nucleus." data-term-url="/en/glossary/view/atomic+number/1512">atomic number</mark> of the resulting <mark class="term" data-term="element" data-term-def="One of fewer than 118 pure chemical substances. An element is a substance composed of atoms with identical atomic number." data-term-url="/en/glossary/view/element/1510">element</mark> increases. The electron is ejected as the radioactive <mark class="term" data-term="particle" data-term-def="A tiny piece of matter." data-term-url="/en/glossary/view/particle/8259">particle</mark>.</p> <p>“Gamma decay” is the loss of <mark class="term" data-term="energy" data-term-def="An abstract property defined as the capacity to do work. The basic forms of energy include chemical, electrical, mechanical, nuclear, and&hellip;" data-term-url="/en/glossary/view/energy/1497">energy</mark> only and does not itself lead to a change in the nucleus of an atom. Gamma (γ) rays are often emitted along with alpha and <mark class="term" data-term="beta particle" data-term-def="An electron released by some radioisotopes during radioactive decay." data-term-url="/en/glossary/view/beta+particle/13608">beta particles</mark>. Gamma rays are represented as $\ce{^0_0\gamma}$ in a nuclear equation. Of the three types of <mark class="term" data-term="radiation" data-term-def="Energy emitted as particles, waves, or rays." data-term-url="/en/glossary/view/radiation/8266">radiation</mark> we have discussed, gamma rays have the greatest penetrating power because they are pure energy, as shown in Figure 5. Even a thin piece of paper can stop <mark class="term" data-term="alpha particle" data-term-def="A type of particle that is ejected from radioactive nuclei. Alpha particles consist of two protons and two neutrons and&hellip;" data-term-url="/en/glossary/view/alpha+particle/1525">alpha particles</mark>; beta particles travel through paper but can be stopped by something denser like aluminum, but thick lead shielding is needed to reduce gamma rays.</p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox="" data-lightbox-src="/img/library/large_images/image_13582.jpg"> <img src="/img/library/modules/mid284/Image/VLObject13582-24082011084304.svg" alt="Figure 5: Relative penetrating power of alpha, beta, and gamma radiation from least to most. " /> </button> <figcaption> <p><strong>Figure 5:</strong> Relative penetrating power of alpha, beta, and gamma radiation from least to most. </p> <span class="credit">image ©<a href="https://commons.wikimedia.org/wiki/File:Alfa_beta_gamma_radiation_penetration.svg"> CC BY-SA 3.0 Ehamberg</a> </span> </figcaption> </figure> </div> <p>Now that we understand these three types of radioactive <mark class="term" data-term="decay" data-term-def="To break down; to decrease over time in size, amount, or force." data-term-url="/en/glossary/view/decay/8265">decay</mark>, we can get back to our discussion of <mark class="term" data-term="radiation" data-term-def="Energy emitted as particles, waves, or rays." data-term-url="/en/glossary/view/radiation/8266">radiation</mark> therapy. Just how does this work? Two types of radiation therapy are used to treat cancer: external <mark class="term" data-term="beam" data-term-def="A ray or shaft of light from a source." data-term-url="/en/glossary/view/beam/8277">beam</mark> radiation therapy and internal radiation therapy. Doctors use medical imaging, like magnetic resonance imaging (MRI), to determine the exact location of cancer <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark>. They also determine the type of therapy and radiation dosage needed to destroy the cancer cells.</p> <p>During external beam radiation therapy, a machine, such as a Gamma Knife, is positioned over the patient to precisely release gamma rays at a location over the cancer cells. Gamma rays damage the <mark class="term" data-term="DNA" data-term-def="Deoxyribonucleic acid. A double-stranded nucleic acid containing the sugar 2-deoxy-D-ribose. A constituent of cellular nuclear material responsible for encoding&hellip;" data-term-url="/en/glossary/view/DNA/1604">DNA</mark> inside of cells so that, over time, the cancer cells stop dividing and die. External beam radiation therapy is used to treat many types of cancer.</p> <p>Other types of cancer are treated with internal radiation therapy. A source of radiation is placed by the cancer cells. As the radioactive <mark class="term" data-term="isotope" data-term-def="Atoms of the same element with different numbers of neutrons in their atomic nucleus. Isotopes have the same chemical properties and&hellip;" data-term-url="/en/glossary/view/isotope/1516">isotope</mark> decays and releases radiation, the cancer cells are killed over time. Brachytherapy uses a <mark class="term" data-term="solid" data-term-def="A collection of atoms or molecules that are held together so that, under constant conditions, they maintain a defined shape and&hellip;" data-term-url="/en/glossary/view/solid/7571">solid</mark> radiation source; by comparison, systemic therapy uses a <mark class="term" data-term="liquid" data-term-def="The state of matter characterized by its condensed nature and ability to flow. Unlike gases, molecules within a liquid often experience&hellip;" data-term-url="/en/glossary/view/liquid/8727">liquid</mark> source of radiation that travels through the blood.</p> <p>Cancer <mark class="term" data-term="treatment" data-term-def="In science, a treatment refers to a method for fixing or manipulating an independent variable in the course of scientific research.&hellip;" data-term-url="/en/glossary/view/treatment/3799">treatments</mark> may include radiation therapy only or radiation therapy combined with surgery, chemotherapy, or immunotherapy. Doctors recommend treatment on a case-by-case basis.</p> <p>Let’s review the three types of radiation:</p><div class='\"table-container\"'><table class="table"> <thead> <th scope="col"></th> <th scope="col">Alpha ($\alpha$)</th> <th scope="col">Beta ($\beta$)</th> <th scope="col">Gamma ($\gamma$)</th> </thead> <tbody> <tr> <td scope="row">Form</td> <td>particle</td> <td>particle</td> <td>energy</td> </tr> <tr> <td scope="row">Symbol</td> <td>$\ce{^4_2He}$</td> <td>$\ce{^0_-1e}$</td> <td>$\ce{^0_0\gamma}$</td> </tr> <tr> <td scope="row">Charge</td> <td>+2</td> <td>-1</td> <td>0</td> </tr> <tr> <td scope="row">Presentation power</td> <td>Low</td> <td>Moderate</td> <td>Very high</td> </tr> </tbody> </table></div> <p>While these are the more common types of nuclear <mark class="term" data-term="decay" data-term-def="To break down; to decrease over time in size, amount, or force." data-term-url="/en/glossary/view/decay/8265">decay</mark> processes, it’s important to note that there are others. <mark class="term" data-term="neutron" data-term-def="A sub-atomic particle with no charge and a mass of 1.675 × 10<sup>-27</sup> kg. Neutrons are found in the nucleus&hellip;" data-term-url="/en/glossary/view/neutron/1520">Neutron</mark> emission (observed by Chadwick), <mark class="term" data-term="electron" data-term-def="A subatomic particle with a negative charge of 1.60 × 10<sup>-19</sup> coulombs and a mass of 9.11 × 10<sup>-31</sup> kg. Electrons&hellip;" data-term-url="/en/glossary/view/electron/852">electron</mark> capture, cluster decay, and other types of pathways exist by which nuclear decay can occur.</p> <div class="comprehension-checkpoint margin-y-4"> <h6 class="comprehension-checkpoint__header"> <span> <span class="icon icon-question"></span> </span> Comprehension Checkpoint </h6> <form class="" name="cc13586"> <div class="form-entry"> <div class="form-entry__field"> <span class="form-entry__field__label">Which type of radioactive decay releases the heaviest particles?</span> <div class="form-entry__option"> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-13586-0-option-a" name="quiz-option-13586" type="radio" value="Beta" > <span class="option__label"> <span class="screen-reader-only">a.</span> Beta </span> </label> <span class="quiz__response" id="response-13586-0"> <strong>Incorrect.</strong> </span> </div> <div class="form-entry__option__radio" data-answer="correct"> <label> <input id="q1-13586-1-option-b" name="quiz-option-13586" type="radio" value="Alpha" > <span class="option__label"> <span class="screen-reader-only">b.</span> Alpha </span> </label> <span class="quiz__response" id="response-13586-1"> <strong>Correct!</strong> </span> </div> </div> </div> </div> </form> </div> </section> <section id="toc_5"> <h2>Half-life and its applications</h2><p>As you have seen, unstable nuclei release <mark class="term" data-term="particle" data-term-def="A tiny piece of matter." data-term-url="/en/glossary/view/particle/8259">particles</mark> and <mark class="term" data-term="energy" data-term-def="An abstract property defined as the capacity to do work. The basic forms of energy include chemical, electrical, mechanical, nuclear, and&hellip;" data-term-url="/en/glossary/view/energy/1497">energy</mark> as <mark class="term" data-term="radiation" data-term-def="Energy emitted as particles, waves, or rays." data-term-url="/en/glossary/view/radiation/8266">radiation</mark> when they undergo nuclear <mark class="term" data-term="decay" data-term-def="To break down; to decrease over time in size, amount, or force." data-term-url="/en/glossary/view/decay/8265">decay</mark>. Depending on the <mark class="term" data-term="element" data-term-def="One of fewer than 118 pure chemical substances. An element is a substance composed of atoms with identical atomic number." data-term-url="/en/glossary/view/element/1510">element</mark> being observed, this <mark class="term" data-term="process" data-term-def="Method, procedure; series of actions or steps." data-term-url="/en/glossary/view/process/8256">process</mark> can take fractions of seconds or billions of years. The decay’s speed depends upon how unstable an <mark class="term" data-term="atom" data-term-def="The smallest unit of an element that retains the chemical properties of the element. Atoms can exist alone or in&hellip;" data-term-url="/en/glossary/view/atom/1509">atom</mark> is: Very unstable atoms decay quicker than others. But the nuclei do not all decay at once. Instead, they decay independently and randomly. One cannot predict exactly when a particular <mark class="term" data-term="nucleus" data-term-def="1. [Atomic] A tiny, dense positively charged mass at the heart of an atom. The nucleus is composed of protons and&hellip;" data-term-url="/en/glossary/view/nucleus/1526">nucleus</mark> will decay, but the <mark class="term" data-term="probability" data-term-def="The likelihood that a given event will occur. In statistics, probability is often expressed as a ratio of the number of&hellip;" data-term-url="/en/glossary/view/probability/3913">probability</mark> of a nucleus undergoing decay can be calculated. When this probability is placed in the context of a <mark class="term" data-term="unit" data-term-def="An accepted quantity used as a standard of measurement. For example, the meter, liter, and gram." data-term-url="/en/glossary/view/unit/848">unit</mark> of time, it is called a “decay <mark class="term" data-term="constant" data-term-def="In mathematics, a quantity that has a fixed value; something that does not vary." data-term-url="/en/glossary/view/constant/8557">constant</mark>.” This leads us to a concept for measuring decay over time called “half-life.”</p> <p>The <mark class="term" data-term="half-life" data-term-def="The time required for half of the original amount of a substance to undergo a process. For example, the time required&hellip;" data-term-url="/en/glossary/view/half~life/1617">half-life</mark> of a radioisotope is the time required for half of the atoms of the radioactive substance to break down or undergo decay. Mathematically, the amount of a radioactive substance that remains after a certain amount of time can be calculated with the equation shown below (Equation 3).</p><div class="figure"><figure><p style="text-align: center;">$$N = N_0e^{-kt}$$</p> <figcaption><strong>Equation 3</strong></figcaption> </figure></div><p><em>N</em> = amount of radioactive substance remaining</p> <p><em>N<sub>0</sub></em> = initial amount of radioactive substance</p> <p><em>e</em> = a <mark class="term" data-term="constant" data-term-def="In mathematics, a quantity that has a fixed value; something that does not vary." data-term-url="/en/glossary/view/constant/8557">constant</mark>, approximately 2.71828</p> <p><em>k</em> = <mark class="term" data-term="decay" data-term-def="To break down; to decrease over time in size, amount, or force." data-term-url="/en/glossary/view/decay/8265">decay</mark> rate/half-life</p> <p><em>t</em> = time</p><p>Equation 3 tells us that the amount of radioactive material that remains after a given time is a <mark class="term" data-term="product" data-term-def="The material that is formed as a result of a chemical reaction. Written on the right side of a chemical equation.&hellip;" data-term-url="/en/glossary/view/product/1569">product</mark> of the initial amount multiplied by the <mark class="term" data-term="constant" data-term-def="In mathematics, a quantity that has a fixed value; something that does not vary." data-term-url="/en/glossary/view/constant/8557">constant</mark> e raised to a negative <mark class="term" data-term="exponent" data-term-def="A number or expression written superscript to another number or expression, called the base, and indicating the power to which the&hellip;" data-term-url="/en/glossary/view/exponent/8759">exponent</mark> that is the product of the <mark class="term" data-term="decay" data-term-def="To break down; to decrease over time in size, amount, or force." data-term-url="/en/glossary/view/decay/8265">decay</mark> rate (half-life and time elapsed). Let’s see how this <mark class="term" data-term="work" data-term-def="A process that occurs when a force acts over a distance, as when an object is moved. Work equals the multiple&hellip;" data-term-url="/en/glossary/view/work/1502">works</mark>. The Curie’s first isolated radium in their lab, and radium-226 has a <mark class="term" data-term="half-life" data-term-def="The time required for half of the original amount of a substance to undergo a process. For example, the time required&hellip;" data-term-url="/en/glossary/view/half~life/1617">half-life</mark> of 1,600 years and a decay rate of 0.693. Using the equation, we can calculate how much of a 1.0 g sample of radium-226 remains after 100 years.</p> <p>$$N = N_0e^{-kt}$$</p> <p><em>N</em> = ?</p> <p><em>N<sub>0 </sub></em>= 1.0 g</p> <p><em>e </em>= a <mark class="term" data-term="constant" data-term-def="In mathematics, a quantity that has a fixed value; something that does not vary." data-term-url="/en/glossary/view/constant/8557">constant</mark>, approximately 2.71828</p> <p><em>k </em>= 0.693/1600 years</p> <p><em>t </em>= 100 years</p> <p> </p> <p><em>N</em> = (1.0 g) $e^{-(\frac{0.693}{1600})(100)}$</p> <p><em>N</em> = 0.958g radium-226 remaining</p><p>So, it should be no surprise that the Curies’ laboratory notebooks are still radioactive. Even after 100 years, most of the trace amount of radium that contaminated them is still present. The amount remaining can also be determined graphically. Figure 6 is a graph showing the amount of radium-226 remaining over time for a 1g sample. Note that at 1,600 years, or one <mark class="term" data-term="half-life" data-term-def="The time required for half of the original amount of a substance to undergo a process. For example, the time required&hellip;" data-term-url="/en/glossary/view/half~life/1617">half-life</mark>, half of one gram remains; at 3,200 years, or two half-lives, one-fourth of one gram remains; and at 4,800 years, or three half-lives, only one-eighth of one gram remains. How long will it take for the sample to <mark class="term" data-term="decay" data-term-def="To break down; to decrease over time in size, amount, or force." data-term-url="/en/glossary/view/decay/8265">decay</mark> so that only one-sixteenth of one gram remains?</p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox=""> <img src="/img/library/modules/mid284/Image/VLObject13595-24082012080113.jpg" alt="Figure 6: A graph of mass of radium versus time representing the half-life of radium-226. " /> </button> <figcaption> <p><strong>Figure 6:</strong> A graph of mass of radium versus time representing the half-life of radium-226. </p> <span class="credit">image ©Visionlearning</span> </figcaption> </figure> </div> <div class="comprehension-checkpoint margin-y-4"> <h6 class="comprehension-checkpoint__header"> <span> <span class="icon icon-question"></span> </span> Comprehension Checkpoint </h6> <form class="" name="cc13596"> <div class="form-entry"> <div class="form-entry__field"> <span class="form-entry__field__label">How much of an original sample of a radioactive element remains after one half-life?</span> <div class="form-entry__option"> <div class="form-entry__option__radio" data-answer="correct"> <label> <input id="q1-13596-0-option-a" name="quiz-option-13596" type="radio" value="1/2" > <span class="option__label"> <span class="screen-reader-only">a.</span> 1/2 </span> </label> <span class="quiz__response" id="response-13596-0"> <strong>Correct!</strong> </span> </div> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-13596-1-option-b" name="quiz-option-13596" type="radio" value="1/4" > <span class="option__label"> <span class="screen-reader-only">b.</span> 1/4 </span> </label> <span class="quiz__response" id="response-13596-1"> <strong>Incorrect.</strong> </span> </div> </div> </div> </div> </form> </div> </section> <section id="toc_6"> <h2>Decay chains</h2><p>Radioisotopes rarely turn into a stable <mark class="term" data-term="element" data-term-def="One of fewer than 118 pure chemical substances. An element is a substance composed of atoms with identical atomic number." data-term-url="/en/glossary/view/element/1510">element</mark> after just one <mark class="term" data-term="decay" data-term-def="To break down; to decrease over time in size, amount, or force." data-term-url="/en/glossary/view/decay/8265">decay</mark> <mark class="term" data-term="process" data-term-def="Method, procedure; series of actions or steps." data-term-url="/en/glossary/view/process/8256">process</mark>. Instead, they go through a “decay chain,” or sequence of nuclear <mark class="term" data-term="reaction" data-term-def="A chemical change when substances come into contact with each other." data-term-url="/en/glossary/view/reaction/8263">reactions</mark>, to reach stability. For example, when radium-226 decays, it releases an <mark class="term" data-term="alpha particle" data-term-def="A type of particle that is ejected from radioactive nuclei. Alpha particles consist of two protons and two neutrons and&hellip;" data-term-url="/en/glossary/view/alpha+particle/1525">alpha particle</mark> to become radon-222. But radon itself is radioactive and undergoes decay to Polonium. You can see in Figure 7 that the radium <mark class="term" data-term="decay chain" data-term-def="A series of nuclear reactions that a radioactive isotope goes through to become more stable." data-term-url="/en/glossary/view/decay+chain/13610">decay chain</mark> actually contains seven distinct steps. And while the first few steps release alpha <mark class="term" data-term="particle" data-term-def="A tiny piece of matter." data-term-url="/en/glossary/view/particle/8259">particles</mark>, <mark class="term" data-term="beta particle" data-term-def="An electron released by some radioisotopes during radioactive decay." data-term-url="/en/glossary/view/beta+particle/13608">beta particles</mark> will also be released as the decay chain continues (Figure 7).</p><p>Radioisotopes rarely turn into a stable <mark class="term" data-term="element" data-term-def="One of fewer than 118 pure chemical substances. An element is a substance composed of atoms with identical atomic number." data-term-url="/en/glossary/view/element/1510">element</mark> after just one <mark class="term" data-term="decay" data-term-def="To break down; to decrease over time in size, amount, or force." data-term-url="/en/glossary/view/decay/8265">decay</mark> <mark class="term" data-term="process" data-term-def="Method, procedure; series of actions or steps." data-term-url="/en/glossary/view/process/8256">process</mark>. Instead, they go through a “decay chain,” or sequence of nuclear <mark class="term" data-term="reaction" data-term-def="A chemical change when substances come into contact with each other." data-term-url="/en/glossary/view/reaction/8263">reactions</mark>, to reach stability. For example, when radium-226 decays, it releases an <mark class="term" data-term="alpha particle" data-term-def="A type of particle that is ejected from radioactive nuclei. Alpha particles consist of two protons and two neutrons and&hellip;" data-term-url="/en/glossary/view/alpha+particle/1525">alpha particle</mark> to become radon-222. But radon itself is radioactive and undergoes decay to Polonium. You can see in Figure 7 that the radium <mark class="term" data-term="decay chain" data-term-def="A series of nuclear reactions that a radioactive isotope goes through to become more stable." data-term-url="/en/glossary/view/decay+chain/13610">decay chain</mark> actually contains seven distinct steps. And while the first few steps release alpha <mark class="term" data-term="particle" data-term-def="A tiny piece of matter." data-term-url="/en/glossary/view/particle/8259">particles</mark>, <mark class="term" data-term="beta particle" data-term-def="An electron released by some radioisotopes during radioactive decay." data-term-url="/en/glossary/view/beta+particle/13608">beta particles</mark> will also be released as the decay chain continues (Figure 7).</p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox=""> <img src="/img/library/modules/mid284/Image/VLObject13600-24082012080330.jpg" alt="Figure 7: The radioactive decay chain of radium-226. " /> </button> <figcaption> <p><strong>Figure 7:</strong> The radioactive decay chain of radium-226. </p> <span class="credit">image ©<a href="https://www.nist.gov/image-23773"> National Institute of Standards and Technology</a> </span> </figcaption> </figure> </div> <p>What else do you notice in this <mark class="term" data-term="decay" data-term-def="To break down; to decrease over time in size, amount, or force." data-term-url="/en/glossary/view/decay/8265">decay</mark> chain (Figure 7)? Each arrow represents a nuclear equation that can be modeled and has its own <mark class="term" data-term="half-life" data-term-def="The time required for half of the original amount of a substance to undergo a process. For example, the time required&hellip;" data-term-url="/en/glossary/view/half~life/1617">half-life</mark>. Some, like the decay of polonium-218, have a half-life measured in minutes. Others, like the decay of lead-210, have half-lives measured in years. The rate of decay of each different <mark class="term" data-term="product" data-term-def="The material that is formed as a result of a chemical reaction. Written on the right side of a chemical equation.&hellip;" data-term-url="/en/glossary/view/product/1569">product</mark> is independent of others.</p> <p>Radium-226 is not the only radioactive <mark class="term" data-term="isotope" data-term-def="Atoms of the same element with different numbers of neutrons in their atomic nucleus. Isotopes have the same chemical properties and&hellip;" data-term-url="/en/glossary/view/isotope/1516">isotope</mark> that goes through a <mark class="term" data-term="decay chain" data-term-def="A series of nuclear reactions that a radioactive isotope goes through to become more stable." data-term-url="/en/glossary/view/decay+chain/13610">decay chain</mark>. Uranium is found naturally in our <mark class="term" data-term="environment" data-term-def="The conditions that surround and affect an organism." data-term-url="/en/glossary/view/environment/8270">environment</mark>, in rocks, <mark class="term" data-term="soil" data-term-def="The loose top layer of Earth’s surface where plants grow, made up of particles of rocks, minerals, and organic material." data-term-url="/en/glossary/view/soil/8563">soil</mark>, and even water, and there are three naturally occurring <mark class="term" data-term="radioisotopes" data-term-def="Forms of elements that have unstable atomic nuclei and undergo decay by releasing parts of their nucleus and energy to the environment." data-term-url="/en/glossary/view/radioisotopes/13607">radioisotopes</mark> of uranium: U-238, U-235, and U-234. More than 99% of all uranium found in the environment is U-238. U-234 makes up less than 1% of the uranium found naturally but gives off more <mark class="term" data-term="radiation" data-term-def="Energy emitted as particles, waves, or rays." data-term-url="/en/glossary/view/radiation/8266">radiation</mark> than U-238. And U-235 is the radioisotope used in nuclear reactors and weapons.</p> <p>Though rare, uranium is an important <mark class="term" data-term="element" data-term-def="One of fewer than 118 pure chemical substances. An element is a substance composed of atoms with identical atomic number." data-term-url="/en/glossary/view/element/1510">element</mark>. The small amount of radiation emitted by naturally occurring uranium as it decays makes up a significant portion of the background radiation around us all the time. As it turns out, U-238 has a half-life of 4.5 billion years! This <mark class="term" data-term="mean" data-term-def="In statistics, mean commonly refers to the arithmetic mean, also called the average, which is one measure of the mid-point of&hellip;" data-term-url="/en/glossary/view/mean/4221">means</mark> that half of a sample of U-238 changes into a more stable form in 4.5 billion years as the remaining sample continues to break down. Uranium is important to the planet as it releases <mark class="term" data-term="heat" data-term-def="A measure of the total internal energy of a substance that can be increased or decreased when objects with different temperatures&hellip;" data-term-url="/en/glossary/view/heat/1506">heat</mark> inside the Earth as it decays. Uranium and other natural radioactive elements inside the Earth, like thorium-232 and potassium-40, account for about half of the heat given off deep inside the Earth.</p> <p>Understanding radioactive decay is especially important to modern science. For example, one way that scientists date very old objects is by radioactive dating. Carbon dating is one example of this. Recall that carbon-14 is a radioactive element, and since all living <mark class="term" data-term="organism" data-term-def="Any connected living system, such as an animal, plant, fungus, or bacterium. Organisms may be composed of a single cell or&hellip;" data-term-url="/en/glossary/view/organism/2171">organisms</mark> on earth contain carbon, they also contain traces of C-14. By understanding the decay of this element over time, scientists can date the remains of animals or plants that lived tens of thousands of years ago. To better understand how <mark class="term" data-term="carbon-14 dating" data-term-def="A technique used to determine the age of an organic object by measuring the amount of the radioactive isotope <sup>14</sup>C in&hellip;" data-term-url="/en/glossary/view/carbon~14+dating/8760">carbon-14 dating</mark> <mark class="term" data-term="work" data-term-def="A process that occurs when a force acts over a distance, as when an object is moved. Work equals the multiple&hellip;" data-term-url="/en/glossary/view/work/1502">works</mark>, you can read our <a href="https://www.visionlearning.com/en/library/Process-of-Science/49/Uncertainty-Error-and-Confidence/157">Uncertainty, Error, and Confidence</a> module.</p> <div class="comprehension-checkpoint margin-y-4"> <h6 class="comprehension-checkpoint__header"> <span> <span class="icon icon-question"></span> </span> Comprehension Checkpoint </h6> <form class="" name="cc13602"> <div class="form-entry"> <div class="form-entry__field"> <span class="form-entry__field__label">Why do radioisotopes go through a decay chain?</span> <div class="form-entry__option"> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-13602-0-option-a" name="quiz-option-13602" type="radio" value="To become less stable" > <span class="option__label"> <span class="screen-reader-only">a.</span> To become less stable </span> </label> <span class="quiz__response" id="response-13602-0"> <strong>Incorrect.</strong> </span> </div> <div class="form-entry__option__radio" data-answer="correct"> <label> <input id="q1-13602-1-option-b" name="quiz-option-13602" type="radio" value="To become more stable" > <span class="option__label"> <span class="screen-reader-only">b.</span> To become more stable </span> </label> <span class="quiz__response" id="response-13602-1"> <strong>Correct!</strong> </span> </div> </div> </div> </div> </form> </div> </section> <section id="toc_7"> <h2>Radioactivity and medical therapies</h2><p>The <mark class="term" data-term="half-life" data-term-def="The time required for half of the original amount of a substance to undergo a process. For example, the time required&hellip;" data-term-url="/en/glossary/view/half~life/1617">half-life</mark> of radioactive <mark class="term" data-term="isotope" data-term-def="Atoms of the same element with different numbers of neutrons in their atomic nucleus. Isotopes have the same chemical properties and&hellip;" data-term-url="/en/glossary/view/isotope/1516">isotopes</mark> is also important in <mark class="term" data-term="radiation" data-term-def="Energy emitted as particles, waves, or rays." data-term-url="/en/glossary/view/radiation/8266">radiation</mark> therapy. Recall that the Curies observed the effects of radiation on their own health. Radium caused skin burns, leading physicians to believe that tumors could be treated with radium. In 1903, American surgeon Dr. Robert Abbe was one of the first physicians to use radium for <mark class="term" data-term="experiment" data-term-def="A test or trial carried out under controlled conditions so that specific actions can be performed and the results can be observed." data-term-url="/en/glossary/view/experiment/8292">experiments</mark> in cancer <mark class="term" data-term="treatment" data-term-def="In science, a treatment refers to a method for fixing or manipulating an independent variable in the course of scientific research.&hellip;" data-term-url="/en/glossary/view/treatment/3799">treatment</mark>. Abbe found that placing a tumor in contact with a source of radium caused the tumor to stop growing. Physicians continued to experiment to determine the dosage of radium needed and ways to deliver it safely to the patient.</p> <p>As <mark class="term" data-term="research" data-term-def="A study or an investigation." data-term-url="/en/glossary/view/research/8257">research</mark> about the use of radium and other <mark class="term" data-term="radioisotopes" data-term-def="Forms of elements that have unstable atomic nuclei and undergo decay by releasing parts of their nucleus and energy to the environment." data-term-url="/en/glossary/view/radioisotopes/13607">radioisotopes</mark> for treating cancer grew in the early part of the 20th century, findings were published in the prestigious journals of the day, such as the <em>Journal of the American Medical Association</em>. However, this did not <mark class="term" data-term="mean" data-term-def="In statistics, mean commonly refers to the arithmetic mean, also called the average, which is one measure of the mid-point of&hellip;" data-term-url="/en/glossary/view/mean/4221">mean</mark> that all physicians began to learn about this life-saving technique. For example, at the time, African American physicians were barred from joining the American Medical Association due to racist policies, let alone being given a sample of radium for research. So, they formed the National Medical Association in 1895 to share information and released their first journal in 1909. While the African American physicians did not have access to the J<em>ournal of the American Medical Association</em>, they relied on pioneers like L. Greeley Brown. Brown was an African American radiologist who had read about the treatment of uterine tumors with radium. In 1918, he published an article in the <em>Journal of the National Medical Association</em> about research on treating uterine tumors with radium to inform his colleagues of the groundbreaking use of radium in treating cancer.</p> <p>However, not all uses of radium turned out so well. As it became more available in the 1920s, radium was considered a “wonder drug.” Radium <mark class="term" data-term="salt" data-term-def="Generally, any ionic compound except those that contain hydroxide or hydrogen ions. Specifically, any compound other than water formed by&hellip;" data-term-url="/en/glossary/view/salt/1575">salts</mark> were placed in all sorts of household <mark class="term" data-term="product" data-term-def="The material that is formed as a result of a chemical reaction. Written on the right side of a chemical equation.&hellip;" data-term-url="/en/glossary/view/product/1569">products</mark>, such as toothpaste, cosmetics, and even water. Figure 8 is an image of a tin that contained cigarettes branded with radium. The thinking went: If radium could shrink cancerous tumors, it must be healthy. Sadly, thousands of people were sickened, and many died due to the careless use of radium in household products. Radium quickly disappeared from household products; however, radium-223 is still used today as a life-saving treatment for bone cancer.</p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox=""> <img src="/img/library/modules/mid284/Image/VLObject13605-24082012080950.jpeg" alt="Figure 8: Tin containing cigarettes branded with radium." /> </button> <figcaption> <p><strong>Figure 8:</strong> Tin containing cigarettes branded with radium.</p> <span class="credit">image ©<a href="https://commons.wikimedia.org/wiki/File:Radium_red_cigaretets_tin,_front.JPG"> Public Domain</a> </span> </figcaption> </figure> </div> <p>The discovery of radiation, radium, radioactivity, types of radioactive decay, and half-life have all contributed to medical success stories in treating cancer with radiation therapy. This has happened in just over a century of experimentation, research, and innovation. As Madame Curie said in a speech at Vassar College in 1921:</p> <blockquote class="blockquote"> <p>We must not forget that when radium was discovered, no one knew that it would prove useful in hospitals. The work was one of pure science. And this is a proof that scientific work must not be considered from the point of view of the direct usefulness of it. It must be done for itself, for the beauty of science, and then there is the chance that a scientific discovery may become like the radium, a benefit for humanity.</p> </p></blockquote> </div> </section> <hr class="border-color-dark" /> <footer class="module__footer"> <p class="citation"> <em> Judi Luepke, PhD. “Nuclear Chemistry I” Visionlearning Vol. CHE-5 (8), 2024. </em> </p>  <div class="title-list" name="further"> <p class="h6 title-list__title"> Further Reading </p> <ul class="grid grid--column-2--md grid--column-3--md gap-1"> <li> <a class="no-hover-focus height-100" href="/en/library/Chemistry/1/Atomic-Theory-I/50"> <article class="flex-row align-items-center flex-column--md align-items-start--md height-100 theme-light padding-2 gap-2"> <div class="width-30 width-auto--md"> <img class="border-radius box-shadow-1" src="/img/library/moduleImages/featured_image_50-23061209064435.jpeg" alt="Atomic Theory I"> </div> <div class="flex-grow-shrink"> <h2 class="h6 font-weight-normal"> Atomic Theory I: <em>Detecting electrons and the nucleus</em> </h2> </div> </article> </a> </li> <li> <a class="no-hover-focus height-100" href="/en/library/Process-of-Science/49/Uncertainty-Error-and-Confidence/157"> <article class="flex-row align-items-center flex-column--md align-items-start--md height-100 theme-light padding-2 gap-2"> <div class="width-30 width-auto--md"> <img class="border-radius box-shadow-1" src="/img/library/moduleImages/featured_image_157-23061210061558.jpeg" alt="Uncertainty, Error, and Confidence"> </div> <div class="flex-grow-shrink"> <h2 class="h6 font-weight-normal"> Uncertainty, Error, and Confidence: <em>Characterizing natural variability and human error</em> </h2> </div> </article> </a> </li> </ul> </div> </footer> </div>   </div>  <div class="order-1 order-2--lg module__tools"> <div class="narrow margin-x-auto position-sticky-top font-size-md"> <div class="padding-2 border-radius box-shadow-1--lg"> <div class="tabs" role="tablist"> <nav> <button class="button button--icon-label" id="tab-button-in-this-module" aria-label="Table of Contents" aria-controls="tab-panel-module__tools" aria-selected="true" role="tab"> <span class="icon icon-list" aria-hidden="true"></span> <span class="button__text">Contents</span> </button> <button class="button button--icon-label" id="tab-button-toggle-terms" aria-controls="tab-panel-toggle-terms" aria-selected="false" role="tab"> <span class="icon icon-glossary-highlight"></span> <span class="button__text">Glossary Terms</span> </button> </nav> <hr class="divider" /> <div class="tabs__panel shown" id="tab-panel-module__tools" aria-labelledby="tab-button-module__tools" role="tabpanel"> <p class="font-weight-bold margin-bottom-1"> Table of Contents </p> <div class="table-of-contents" id="module-toc"> <ul> <li><a href="/en/library/chemistry/1/nuclear-chemistry-i/284#toc_1">The discovery of radiation and radium</a> </li> <li><a href="/en/library/chemistry/1/nuclear-chemistry-i/284#toc_2">Radioactivity</a> </li> <li><a href="/en/library/chemistry/1/nuclear-chemistry-i/284#toc_3">Radioactive isotopes</a> </li> <li><a href="/en/library/chemistry/1/nuclear-chemistry-i/284#toc_4">Types of radioactive decay</a> </li> <li><a href="/en/library/chemistry/1/nuclear-chemistry-i/284#toc_5">Half-life and its applications</a> </li> <li><a href="/en/library/chemistry/1/nuclear-chemistry-i/284#toc_6">Decay chains</a> </li> <li><a href="/en/library/chemistry/1/nuclear-chemistry-i/284#toc_7">Radioactivity and medical therapies</a> </li> </ul> </div> </div>   <div class="tabs__panel" id="tab-panel-toggle-terms" aria-labelledby="tab-button-toggle-terms" role="tabpanel"> <div class="reading-toggle"> <div class="reading-toggle__switch"> <div class="form-entry__option__switch"> <label> <input type="checkbox" name="termsToggleSwitch" id="terms-toggle-switch" /> <span class="switch__slider"></span> <span class="option__label text-decoration-none font-size-md"> Highlight Glossary Terms </span> </label> </div> </div> <div class="reading-toggle__help"> <p> <em> Activate glossary term highlighting to easily identify key terms within the module. Once highlighted, you can click on these terms to view their definitions. </em> </p> </div> </div> </div> <div class="tabs__panel" id="tab-panel-toggle-ngss" aria-labelledby="tab-button-toggle-ngss" role="tabpanel"> <div class="reading-toggle"> <div class="reading-toggle__switch"> <div class="form-entry__option__switch"> <label> <input type="checkbox" name="ngssToggleSwitch" id="ngss-toggle-switch" /> <span class="switch__slider"></span> <span class="option__label text-decoration-none font-size-md"> Show NGSS Annotations </span> </label> </div> </div> <div class="reading-toggle__help"> <p> <em> Activate NGSS annotations to easily identify NGSS standards within the module. 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Nuclear Chemistry I | Chemistry | Visionlearning