Electrically neutral elementary particles found in all atomic nuclei except light hydrogen; the mass is equal to that of the proton and electron combined and they are unstable when isolated from the nucleus, undergoing beta decay. Slow, thermal, epithermal, and fast neutrons refer to the energy levels with which the neutrons are ejected from heavier nuclei during their decay.
An electrically neutral particle located in the nucleus of the atom.
Small atomic particle similar in mass to a proton but without an electrical charge.
A subatomic particle equal in mass to a proton but without an electric charge. It is believed to be a particle of all nuclei of mass number greater than one.
The smallest unit of neutral electric charge present within the nucleus of an atom is referred to as an elementary charge.