Particles in the Nucleus

A stable nucleus, which is not radioactive, contains protons and neutrons. A neutron is electrically neutral without any net charge. Its mass is almost the same as a proton.

A proton has the positive charge of a hydrogen nucleus. The charge is the same amount as that of an orbital electron but of opposite polarity. There are no electrons in the nucleus. Table 3 lists the charge and mass for these three basic particles in all atoms.