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This is a list of radioactive nuclides (sometimes also called isotopes), ordered by half-life from shortest to longest, in seconds, minutes, hours, days and years. Current methods make it difficult to measure half-lives between approximately 10 −19 and 10 −10 seconds.
In this situation it is generally uncommon to talk about half-life in the first place, but sometimes people will describe the decay in terms of its "first half-life", "second half-life", etc., where the first half-life is defined as the time required for decay from the initial value to 50%, the second half-life is from 50% to 25%, and so on. [7]
Phosphorus-32 only exists in small quantities on Earth as it has a short half-life of 14 days and so decays rapidly. Phosphorus is found in many organic molecules , and so, phosphorus-32 has many applications in medicine , biochemistry , and molecular biology where it can be used to trace phosphorylated molecules (for example, in elucidating ...
Absorption half-life 1 h, elimination half-life 12 h. Biological half-life ( elimination half-life , pharmacological half-life ) is the time taken for concentration of a biological substance (such as a medication ) to decrease from its maximum concentration ( C max ) to half of C max in the blood plasma .
Radon-222 itself alpha decays to polonium-218 with a half-life of approximately 3.82 days, making it the most stable isotope of radon. [1] Its final decay product is stable lead-206 . In theory, 222 Rn is capable of double beta decay to 222 Ra, and depending on the mass measurement, single beta decay to 222 Fr may also be allowed.
After one half-life has elapsed, one half of the atoms of the nuclide in question will have decayed into a "daughter" nuclide or decay product. In many cases, the daughter nuclide itself is radioactive, resulting in a decay chain , eventually ending with the formation of a stable (nonradioactive) daughter nuclide; each step in such a chain is ...
Alternatively, since the radioactive decay contributes to the "physical (i.e. radioactive)" half-life, while the metabolic elimination processes determines the "biological" half-life of the radionuclide, the two act as parallel paths for elimination of the radioactivity, the effective half-life could also be represented by the formula: [1] [2]
The half-life of La-140 is 40.224 hours; it undergoes beta decay to stable cerium-140. It was prepared from barium-140, a common fission product isolated from the spent fuel from the Oak Ridge National Laboratory X-10 Graphite Reactor , [ 14 ] and later, after 1948, also from the Hanford Site plutonium-239 producing nuclear reactors .