Presentation on theme: "CHAPTER 22 Nuclear Chemistry"— Presentation transcript:
1 CHAPTER 22 Nuclear Chemistry II. Radioactive Decay(p )IIIIIIV
2 A. Types of Radiation 2+ 1- 1+ Alpha particle () helium nucleus paper2+Beta particle (-)electron1-leadPositron (+)positron1+concreteGamma ()high-energy photon
3 B. Nuclear Decay Numbers must balance!! Alpha Emission parent nuclide daughternuclidealphaparticleNumbers must balance!!
4 B. Nuclear DecayBeta EmissionelectronPositron Emissionpositron
5 B. Nuclear Decay Electron Capture electron Gamma Emission Usually follows other types of decay.TransmutationOne element becomes another.
6 B. Nuclear Decay Why nuclides decay… need stable ratio of neutrons to protonsDECAY SERIES TRANSPARENCY
7 C. Half-life Half-life (t½) Time required for half the atoms of a radioactive nuclide to decay.Shorter half-life = less stable.
8 C. Half-lifemf: final massmi: initial massn: # of half-lives
9 C. Half-life t½ = 5.0 s mf = mi (½)n mi = 25 g mf = (25 g)(0.5)12 Fluorine-21 has a half-life of 5.0 seconds. If you start with 25 g of fluorine-21, how many grams would remain after 60.0 s?GIVEN:t½ = 5.0 smi = 25 gmf = ?total time = 60.0 sn = 60.0s ÷ 5.0s =12WORK:mf = mi (½)nmf = (25 g)(0.5)12mf = g