Nuclear Chemistry

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Nuclear Chemistry

• Unstable Nuclides

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Belt of Stability
Stable nuclides have N/Z ratios from 1 to 1.52.
All nuclides that lie outside this belt are
unstable and undergo nuclear reactions until they
become a stable nuclide.
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Radioactivity

• Process in which an unstable nucleus is
  ultimately converted to a stable nucleus by means
  of nuclear reactions
• All nuclei having Z gt 83 and a few having Z lt 83
  are unstable
• The emission of energetic particles during a
  nuclear change is called radiation

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Types of Radiation
Buell/Girard, "Chemistry", Prentice Hall,
NJ,1994, 152
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Natural Radiation
Tro, 185
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Penetrating Power
http//www.princeton.edu/ehs/radtrain/Modules/bas
ics.html
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Equations for Natural Radioactivity
Alpha Radiation
Beta Radiation
Gamma Radiation
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Half-Life

• Half-life is the time required for half of the
  radioactive nuclei in a sample to decay
• After n-half-lives, the fraction of the original
  radioactive nuclei still remaining is 1/2n

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Half-life
Joesten et al, Chemistry Impact on Society,
Saunders, NY, 1988, 68.
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5730 y
McMurray/Fay, "Chemistry", Prentice Hall, NJ,
1995,885
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Joesten/Wood, "World of Chemistry,2nd,
Saunders,PA, 1996,122
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U to Pb Dating
Oldest rocks found on surface of Earth contain
50U and 50 Pb. Estimate the age of planet Earth
Tro, 202
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Dating of Samples that Contain Carbon
Half-life 5730 yr
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Carbon Dating
Object
Tro, 200
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Summary of Nuclear Chemistry
http//www.lbl.gov/abc/