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1 Νοε 2023 · Polonium-210 (210 Po) is typically artificially produced in nuclear reactors by bombarding the stable isotope bismuth-209 (209 Bi) (via the (n, γ) reaction, yielding 210 Bi, which decays with a half-life of T = 5 days to 210 Po) (Health Physics Society, 2008). Determining the atomic mass of polonium was a very challenging task.
All atomic nuclei of the chemical element polonium are summarized under polonium isotopes; these all consist of an atomic nucleus with 84 protons and, in the uncharged state, 84 electrons. The difference between each polonium isotope is based on the number of neutrons in the nucleus.
13 Οκτ 2023 · Polonium has 29 isotopes with known half-lives, with mass numbers ranging from 190 Po to 218 Po. None of them are secure. The most stable isotope, having a half-life of 102 years, is 209 Po. Polonium has an atomic number of 84 and is a silvery metal. It has a melting point of 254 °C (489 °F) and a boiling point of 962 °C ( 1764 °F).
Polonium has 42 known isotopes, all of which are radioactive. They have atomic masses that range from 186 to 227 u . 210 Po (half-life 138.376 days) is the most widely available and is manufactured via neutron capture by natural bismuth .
Today, all isotopes between mass numbers 193 and 218 are known. The longest-lived isotope is 209 Po (t 1/2 = 102 years). Nearly all the chemical and physical studies on polonium were performed with the pure α emitter 210 Po (t 1/2 =138 day). Figure 1 shows the naturally occurring polonium isotopes.
Its abundance in the Earth’s crust is about one part in 10 15. It occurs in nature as a radioactive decay product of uranium, thorium, and actinium. The half-lives of its isotopes range from a fraction of a second up to 103 years; the most common natural isotope of polonium, polonium-210, has a half-life of 138.4 days.
Isotopes. Atoms of the same element with different numbers of neutrons. Key for isotopes
