Isotopes of the same element have the same number of protons and electrons when in neutral atomic form. Different isotopes have different numbers of neutrons in their nuclei, resulting in different atomic weights for the different isotopes of a single element. read more
Isotopes of the same element differ in the number of neutrons contained within the nucleus of the element's atoms, which causes them to differ in their atomic weights. Some isotopes are more radioactive and unstable than others. read more