The nucleus is the dense core of an atom or ion in which neutrons and protons (collectively called nucleons) reside, and which contains most of the atomic mass. The study of nuclei, their properties, and decay is called nuclear physics.
Atom, Atomic Mass Number, Binding Energy, Ion, Neutron, Nucleon, Nuclide, Proton, Weizsäcker's Semi-Empirical Mass Formula
