Radioisotopes in radioactive dating updating articles of incorporation
Elements heavier than lead, and the elements technetium and promethium, exist only as radionuclides.
(In theory, elements heavier than dysprosium exist only as radionuclides, but the half-life for some such elements, e.g. Unplanned exposure to radionuclides generally has a harmful effect on living organisms including humans, although low levels of exposure occur naturally without harm.
The radioactive decay can produce a stable nuclide or will sometimes produce a new unstable radionuclide which may undergo further decay.
Radioactive decay is a random process at the level of single atoms: it is impossible to predict when one particular atom will decay.) for that collection can be calculated from their measured decay constants.
During those processes, the radionuclide is said to undergo radioactive decay.
Radionuclides occur naturally or are artificially produced in nuclear reactors, cyclotrons, particle accelerators or radionuclide generators.Most of those are only produced artificially, and have very short half-lives.For comparison, there are about 252 stable nuclides.Many of these radionuclides exist only in trace amounts in nature, including all cosmogenic nuclides.Secondary radionuclides will occur in proportion to their half-lives, so short-lived ones will be very rare.