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Isotopes of nobelium 54 s activity was actually due to No and the isotope No was retracted. Isotopes of nobelium Nobelium (No) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized (and correctly identified) was No in 1966. There are 12 known radioisotopes, which are No to No and No, and 3 isomers, No, No, and No. The longest-lived isotope is No with a half-life of 58 minutes. The longest-lived isomer is No with a half-life of 1.7 seconds. This cold fusion reaction was