35.2: Introduction
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- 29319
Radioactive decay is the process of an atom changing into a different type of atom; it is a change in the number of protons. Half-life is the time it takes for one half of a sample of radioactive atoms to decay, so that half of the original number of atoms have decayed. Each radioactive isotope has its own half-life. The half-life of an isotope of carbon may be used to determine the age of a fossil. The amount of a radioactive isotope remaining in a sample indicates the approximate age of the sample.
Radioactive Isotope |
Half-life |
---|---|
\(\ce{_{94}^{239}Pu}\) |
24,400 years |
\(\ce{_{92}^{238}U}\) |
4.51 x 109 years |
\(\ce{_{84}^{214}Po}\) |
0.00016 seconds |
\(\ce{_{83}^{210}Bi}\) |
5 days |
\(\ce{_{82}^{210}Pb}\) |
20.4 years |
\(\ce{_{6}^{14}C}\) |
5,730 years |