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NUCLEAR CHEMISTRY

NUCLEAR CHEMISTRY. CHAPTER 21.1 Types of Radioactivity. Discovery of Radioactivity. Radiation: Energy that is spontaneously released from, or given off, by an object Accidentally discovered by Henri Becquerel in 1896

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NUCLEAR CHEMISTRY

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  1. NUCLEAR CHEMISTRY CHAPTER 21.1 Types of Radioactivity

  2. Discovery of Radioactivity • Radiation: Energy that is spontaneously released from, or given off, by an object • Accidentally discovered by Henri Becquerel in 1896 • Becquerel was studying a phosphorescent uranium compound when he discovered that it gave off, what he thought, was radiation. • To verify his hypothesis he sent his work to Marie Curie • Curie concluded that a nuclear reaction was occurring inside the uranium atoms because it had an unstable nucleus

  3. Radioactivity • Definition: the spontaneous emission of energy/radiation by an unstable atomic nucleus • Radioactive elements • Uranium • Plutonium • Radium • Radon • Curium

  4. Nuclear Reactions • During a nuclear reaction a nucleus can gain or lose protons and neutrons • What would happen if you gained or lost protons? • The identity of the element would change. • You can represent nuclear reactions with equations REACTANTS PRODUCTS PARENT ELEMENT DAUGHTER ELEMENT

  5. Types of Radiation • Alpha radiation • Consist of alpha particles. (α) • Helium nuclei being emitted from the nucleus U Th + He Uranium-238  Thorium-234 + Alpha particle • Do not travel far due to large mass (most massive of the particles) • Are not very penetrating- easily stopped by skin or paper • Only dangerous if ingested • Has a +2 charge • Symbol: 42 He

  6. Types of Radiation • Beta Radiation • Consist of beta particles (β) • Fast moving electrons formed by the decomposition of a neutron in an atom. N  H + e Neutron  proton + electron (beta particle) • The neutron decomposes into a proton, which remains in the nucleus, and an electron, which is released from the atom • Charge of -1 • These are more penetrating because they have less charge and less mass • Stopped by aluminum foil or thin pieces of wood • Symbol: 0-1e

  7. Types of Reactions • Gamma Radiation • Consist of gamma rays (ϒ) • High energy form of radiation because has no mass or charge • Penetrates almost everything and can seriously harm living cells • Can be stopped by thick blocks of lead or thicker blocks of concrete • Symbol:00Υ

  8. How far can they go?

  9. Detecting Radioactivity • Radioactivity cannot be seen, heard, smelled, tasted, or touched….so how do we know its there? • Photographic film • If the source of radioactivity is nearby • People who work near radiation wear film badges showing their exposure levels • Geiger counter • An instrument that senses radioactive particles

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