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Platinum also has 38 synthetic isotopes ranging in atomic mass from 165 to 208, making the total number of known isotopes 44. The least stable of these are 165 Pt and 166 Pt, with half-lives of 260 μs, whereas the most stable is 193 Pt with a half-life of 50 years. Most platinum isotopes decay by some combination of beta decay and alpha decay ...
Gold is currently considered the heaviest monoisotopic element. Bismuth formerly held that distinction until alpha-decay of the 209 Bi isotope was observed. All isotopes of gold are either radioactive or, in the case of 197 Au, observationally stable, meaning that 197 Au is predicted to be radioactive but no actual decay has been observed. [4]
Naturally occurring platinum (78 Pt) consists of five stable isotopes (192 Pt, 194 Pt, 195 Pt, 196 Pt, 198 Pt) and one very long-lived (half-life 4.83×10 11 years) radioisotope (190 Pt). There are also 34 known synthetic radioisotopes , the longest-lived of which is 193 Pt with a half-life of 50 years.
The price is high and varying (see table). Illustrative factors that affect the price include oversupply of Ir crucibles [79] [81] and changes in LED technology. [82] Platinum metals occur together as dilute ores. Iridium is one of the rarer platinum metals: for every 190 tonnes of platinum obtained from ores, only 7.5 tonnes of iridium is ...
For isotopes with atomic mass unit values less than that of the most abundant stable isotope, 106 Pd, the primary decay mode is electron capture with the primary decay product being rhodium. The primary mode of decay for those isotopes of Pd with atomic mass greater than 106 is beta decay with the primary product of this decay being silver. [14]
This infobox contains the table of § Main isotopes, and the § Standard atomic weight. For example, {{Infobox uranium isotopes}}, as used on page Isotopes of uranium. The main isotopes table is reused in the regular Infobox: {{Infobox uranium}}.
However, the relative atomic mass of each isotope is quite close to its mass number (always within 1%). The only isotope whose atomic mass is exactly a natural number is 12 C, which has a mass of 12 Da; because the dalton is defined as 1/12 of the mass of a free neutral carbon-12 atom in the ground state.
The relative atomic mass (a weighted average, weighted by mole-fraction abundance figures) of these isotopes is the atomic weight listed for the element in the periodic table. The abundance of an isotope varies from planet to planet, and even from place to place on the Earth, but remains relatively constant in time (on a short-term scale).