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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.
Polonium in the body has a biological half-life of about 30 to 50 days. Caesium in the body has a biological half-life of about one to four months. Mercury (as methylmercury) in the body has a half-life of about 65 days. Lead in the blood has a half life of 28–36 days. [29] [30] Lead in bone has a biological half-life of about ten years.
Boron (5 B) naturally occurs as isotopes 10 B and 11 B, the latter of which makes up about 80% of natural boron. There are 13 radioisotopes that have been discovered, with mass numbers from 7 to 21, all with short half-lives, the longest being that of 8 B, with a half-life of only 771.9(9) ms and 12 B with a half-life of 20.20(2) ms.
The shortest-lived is 7 B, with a half-life of a mere 350±50 × 10 −24 s, being the boron isotope with the fewest neutrons and a half-life long enough to measure. Some radioisotopes have important roles in scientific research; a few are used in the production of goods for commercial use or, more rarely, as a component of finished products.
There are 13 known isotopes of boron; the shortest-lived isotope is 7 B which decays through proton emission and alpha decay with a half-life of 3.5×10 −22 s. Isotopic fractionation of boron is controlled by the exchange reactions of the boron species B(OH) 3 and [B(OH) 4] −.
A chart or table of nuclides maps the nuclear, or radioactive, behavior of nuclides, as it distinguishes the isotopes of an element.It contrasts with a periodic table, which only maps their chemical behavior, since isotopes (nuclides that are variants of the same element) do not differ chemically to any significant degree, with the exception of hydrogen.
232 Th is one of the two nuclides beyond bismuth (the other being 238 U) that have half-lives measured in billions of years; its half-life is 14.05 billion years, about three times the age of the Earth, and slightly longer than the age of the universe. Four-fifths of the thorium present at Earth's formation has survived to the present.
Beryllium-10 (10 Be) is a radioactive isotope of beryllium.It is formed in the Earth's atmosphere mainly by cosmic ray spallation of nitrogen and oxygen. [3] [4] [5] Beryllium-10 has a half-life of 1.39 × 10 6 years, [6] [7] and decays by beta decay to stable boron-10 with a maximum energy of 556.2 keV.