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The longest-lived radioisotopes are 205 Pb with a half-life of 17.3 million years and 202 Pb with a half-life of 52,500 years. A shorter-lived naturally occurring radioisotope, 210 Pb with a half-life of 22.2 years, is useful for studying the sedimentation chronology of environmental samples on time scales shorter than 100 years. [5]
Polonium-210. Polonium-210 (210 Po, Po-210, historically radium F) is an isotope of polonium. It undergoes alpha decay to stable 206 Pb with a half-life of 138.376 days (about 4⁄ months), the longest half-life of all naturally occurring polonium isotopes (210–218 Po). [1] First identified in 1898, and also marking the discovery of the ...
Isotopes of polonium (84Po) There are 42 isotopes of polonium (84 Po). They range in size from 186 to 227 nucleons. They are all radioactive. 210 Po with a half-life of 138.376 days has the longest half-life of any naturally-occurring isotope of polonium and is the most common isotope of polonium. It is also the most easily synthesized polonium ...
210 Po (half-life 138.376 days) is the most widely available and is made via neutron capture by natural bismuth. The longer-lived 209 Po (half-life 124 years, longest-lived of all polonium isotopes) [3] and 208 Po (half-life 2.9 years) can be made through the alpha, proton, or deuteron bombardment of lead or bismuth in a cyclotron. [35]
lead-192: 3.5 210 americium-236: 3.6 220 astatine-220: 3.71 223 ... Radioactive isotope table "lists ALL radioactive nuclei with a half-life greater than 1000 ...
Lead-210 is particularly useful for helping to identify the ages of samples by measuring its ratio to lead-206 (both isotopes are present in a single decay chain). [51] In total, 43 lead isotopes have been synthesized, with mass numbers 178–220. [38] Lead-205 is the most stable radioisotope, with a half-life of around 1.70 × 10 7 years.
The isotope 210 Po is the penultimate member of the uranium-radium-decay series; it decays into a stable lead-isotope with a half-life of 138 days. In almost all cases, the decay is via the emission of an alpha particle of 5.305 MeV .
Half-life (symbol t½) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable atoms survive. The term is also used more generally to characterize any type of exponential (or, rarely ...