Radioactive Elements:

How is it possible that certain elements can change into other elements?

e x / atoms of carbon can become atoms of nitrogen

<<Radioactive Decay: process where atomic nuclei of radioactive isotopes release fast-moving particles and energy<<

during radioactive decay, the identity of an atom changes

radioactive decay is an example of a nuclear reaction

<<Nuclear Reactions: involve the particles in the nucleus of an atom<<

<<ex/ Nuclear Fission: process in which atomic nuclei split apart<<

<<ex/ Nuclear Fusion: process in which atomic nuclei join together<<

both examples of a nuclear reaction

These physical processes make it possible for scientists to turn one element into another

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1896- French scientist Henri Becquerel accidentally discovered the effects of Radioactive Decay

<<Radioactivity: when an element (uranium) spontaneously emits radiation, named by Marie Curie, worked on by Marie Curie, her husband chemist Pierre Curie, and Becquerel who presented his findings to the Curie’s<<

All three were awarded Nobel Prize in Physics

Marie had another one later for her research in Radioactive Elements. She died of cancer, as a result of exposure to radium.

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<<Alpha Particle: consists of two protons + two neutrons; positively charged<<

<<the release of this particle during alpha decay decreases the atomic number by two and the mass number by 4<<

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<<Beta Particle: fast-moving electron given off by a nucleus during radioactive decay. A new proton remains inside the nucleus, nucleus is then left w/ one less neutron + one more proton. Mass # stays the same, but its atomic # increases by 1<<

<<during beta decay, a neutron in an unstable nucleus changes into a negatively charged beta particle + a proton<<

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<<Gamma Rays(also known as gamma radiation): consist of high-energy waves, similar to x-rays. They have no charge + do not cause a change in either the atomic mass or the atomic #<<

<<Alpha + Beta decay are almost always accompanied by gamma radiation<<

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<<Uses of Radioactive isotopes: determining the ages of fossils, tracing the steps of a chemical reaction and industrial processes, diagnosing and treating disease, and providing sources of energy<<

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<<Half-life: (of a radioactive substance) the length of time needed for half of the atoms of a sample to decay, different for each radioactive isotope (can range from less than a second to billions of years)<<

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<<Radioactive Dating: when scientists measure the amount of carbon-14 in a preserved fossil to calculate how many half-lives have passed since it died and estimate the age<<

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<<Tracers: radioactive isotopes that can be followed through the steps of a chemical reaction or an industrial process. They behave chemically like nonradioactive forms of an element<<

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