Isotope "nuclide", and is still sometimes used in contexts where "nuclide" might be more appropriate, such as nuclear technology and nuclear medicine. An isotope and/or nuclide is specified by the name of the particular element (this indicates the atomic number) followed by a hyphen and the mass number (e.g. helium-3, helium-4, carbon-12, carbon-14, uranium-235 and uranium-239). When a chemical symbol is used, e.g. "C" for carbon, standard notation (now known as "AZE notation" because "A" is the mass number, "Z" the atomic number, and E for element) is to indicate the mass number (number of nucleons) with a superscript at the
Isotopes of fermium not confirmed in 1997. Isotopes of fermium Fermium (Fm) is a synthetic element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be discovered (in fallout from nuclear testing) was Fm in 1952. Fm was independently synthesized shortly after the discovery of Fm. There are 20 known radioisotopes ranging in atomic mass from Fm to Fm (Fm is unconfirmed), and 2 nuclear isomers, Fm and Fm. The longest-lived isotope is Fm with a half-life of 100.5 days, and the longest-lived isomer is Fm with a half-life of