Therefore the concentration is
| 1200 |
| 9 × 10⁴ × 300 |
FOOTNOTES
[1]There are exceptions. For a few elements there are no stable nuclei. In some cases, there are other differences that make certain atoms radioactive.
[2]These gamma rays (called prompt gamma rays because they are instantaneously produced when the neutron is captured) can also be used for analysis and sometimes are, but we will not be discussing this type of analysis in this booklet.
[3]Sensitivity in this case means how small an amount of an unknown element can be detected.
[4]Nuclide is a general term applicable to all atomic forms of elements. Whereas isotopes are the various forms of a single element (hence are a family of nuclides) and all have the same atomic number and number of protons, nuclides comprise all the isotopic forms of all the elements.
[5]The half-life of a radioactive nuclide is the time it takes for half the nuclei in a large sample to undergo decay. Note that after half of them are gone, a second half-life period will reduce the remainder by one half, leaving one quarter of the original number.
[6]The disintegration constant is related to the half-life, T½, by the expression: λ = natural logarithm of 2/half-life, or
λ =