nuclide A widely used alternative name for an atom. The composition of any nuclide can be given by means of the chemical symbol of the element, the mass number written as a superscript, and the atomic number written as a subscript. For example, ¹⁴₆C is an atom of carbon (C) having six protons (the atomic number) and 14 nucleons (the mass number).

nuclide A widely used alternative name for an atom. The composition of any nuclide can be given by means of the chemical symbol of the element, with the mass number written as a superscript, and the atomic number written as a subscript (e.g. ¹⁴₆C is an atom of carbon (C) having six protons (the atomic number) and 14 nucleons (the mass number).