Atomic nucleus - Definition and properties
The atomic nucleus is the small central part of the atom, with a positive electric charge and in which most of the mass of the atom is concentrated. Ernest Ruthenford discovered it in 1911. After the discovery of the neutron, in 1932, the atomic nucleus model was quickly developed by Dmitri Ivanenko and Werner Heisenberg.
The major subatomic particles in the nuclei of atoms are protons and neutrons or nucleons (except ordinary hydrogen, which contains only one proton). A single chemical element is characterized by the number of protons in the nucleus that determines the total positive charge. This number is called the atomic number. The mass number is the total of protons and neutrons.
Nuclear physics is the scientific branch that deals with the study and understanding of the atomic nucleus, including the forces that unite it and its composition.
Properties of the atomic nucleus
Nearly all the mass of an atom is in the nucleus, with a very small contribution of the cloud of electrons because the electrons weigh very little in comparison with the neutrons and protons. Protons and neutrons are joined to form the atomic nucleus by nuclear force.
Last review: August 30, 2017