Each nucleus has a (positive) charge Ze , and integer number times the elementary charge e . This follows from the fact that atoms are neutral! Nuclei of identical charge come in different masses, a...Each nucleus has a (positive) charge Ze , and integer number times the elementary charge e . This follows from the fact that atoms are neutral! Nuclei of identical charge come in different masses, all approximate multiples of the “nucleon mass”. Nuclei of identical charge (chemical type) but different mass are called isotopes. Nuclei of approximately the same mass, but different chemical type, are called isobars.
