Nukleids

Nukleids, known in English as nuclides, are the distinct species of atomic nuclei defined by their proton number Z and neutron number N. Each nuclide has a mass number A = Z + N. The term refers to the nucleus itself, apart from the surrounding electrons. Nuclides with the same Z but different N are isotopes of the same element; nuclides with the same A but different Z are isobars, and those with the same N are isotones.

Nuclides can be stable or radioactive. Stable nuclides do not undergo spontaneous decay, while radioactive nuclides decay over characteristic timescales through processes such as alpha decay, beta decay (minus or plus), or gamma emission. Some nuclides exist in excited nuclear states, leading to short-lived isomeric forms.

Notation for nuclides typically shows the mass number and elemental symbol, for example carbon-14 written as 14C. In fuller nuclear notation, the nucleus is specified by Z and N. Well-known nuclides include protium (1H), carbon-12 (12C), carbon-14 (14C), and uranium-235 (235U).

Natural nuclides occur in matter and space, comprising both stable and certain radioactive species (such as 14C and 40K). Artificial nuclides are produced in reactors and particle accelerators and have wide applications. They are used in medicine (diagnostic and therapeutic radioisotopes), archaeology and geology (radiometric dating), industry (tracers and imaging), and energy research.

In summary, nukleids provide a framework for describing nuclear properties across the periodic table, independent of electronic structure.