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Chapter 21 Nuclear Chemistry. 21.1 Radioactivity. Review from Ch. 2 Subatomic particles Atoms are neutral: # protons = # electrons Isotopes – atoms with same number of protons but different number of neutrons. Nuclear Chemistry deals with only the nucleus.
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21.1 Radioactivity • Review from Ch. 2 • Subatomic particles • Atoms are neutral: # protons = # electrons • Isotopes – atoms with same number of protons but different number of neutrons
Nuclear Chemistry deals with only the nucleus. • nuclide – nucleus with specified number of protons and neutrons • radioactivity – spontaneous emission of radiation • radionuclide – radioactive nuclide • radioisotopes – atoms containing radioactive nuclei • radioactive decay – spontaneous decomposition to form a different, more stable, nucleus with the production of one or more particles • decay series – multiple decay steps through which radioactive nuclides go to reach a stable state
Nuclear Equations – sum of both mass and atomic numbers on both sides of equation are equal Examples: 6831Ga + 0-1e → _____ 21287Fr → 20885At + ______ 263106Sg → ______ + 42He
21.4 Rates of Radioactive Decay • Radioactive decay follows 1st order kinetics. • All half-lives are equal. N – # of radioactive nuclei k – decay constant Individual half-lives vary tremendously 214Po 2 x 10-4 s 144Nd 5 x 1015 year