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Printable version; In other projects Wikidata item; Appearance. move to sidebar hide. ... Pages in category "Lists of isotopes by element" The following 122 pages are ...
[c] For a list of primordial nuclides in order of half-life, see List of nuclides. [citation needed] 118 chemical elements are known to exist. All elements to element 94 are found in nature, and the remainder of the discovered elements are artificially produced, with isotopes all known to be highly radioactive with relatively short half-lives ...
When it was realized that all of these are isotopes of the same element, many of these names fell out of use, and "radium" came to refer to all isotopes, not just 226 Ra, [5] though mesothorium 1 in particular was still used for some time, with a footnote explaining that it referred to 228 Ra. [6] Some of radium-226's decay products received ...
A nuclide is a species of an atom with a specific number of protons and neutrons in the nucleus, for example, carbon-13 with 6 protons and 7 neutrons. The nuclide concept (referring to individual nuclear species) emphasizes nuclear properties over chemical properties, whereas the isotope concept (grouping all atoms of each element) emphasizes chemical over nuclear.
Eighteen isotopes and four nuclear isomers are known for einsteinium, with mass numbers 240–257. [2] All are radioactive; the most stable one, 252 Es, has half-life 471.7 days. [44] The next most stable isotopes are 254 Es (half-life 275.7 days), [45] 255 Es (39.8 days), and 253 Es (20.47 days). All the other isotopes have half-lives shorter ...
The column labeled "energy" denotes the energy equivalent of the mass of a neutron minus the mass per nucleon of this nuclide (so all nuclides get a positive value) in MeV, formally: m n − m nuclide / A, where A = Z + N is the mass number. Note that this means that a higher "energy" value actually means that the nuclide has a lower energy.
All biologically active elements exist in a number of different isotopic forms, of which two or more are stable. For example, most carbon is present as 12 C, with approximately 1% being 13 C. The ratio of the two isotopes may be altered by biological and geophysical processes, and these differences can be utilized in a number of ways by ecologists.
Natural isotopes are either stable isotopes or radioactive isotopes that have a sufficiently long half-life to allow them to exist in substantial concentrations in the Earth (such as bismuth-209, with a half-life of 1.9 × 10 19 years, potassium-40 with a half-life of 1.251(3) × 10 9 years), daughter products of those isotopes (such as 234 Th, with a half-life of 24 days) or cosmogenic ...