Isotopes of the same element will have a different number of neutrons, but the same number of protons

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.

each played a major role in ending the cold war.

i confess that there are several parts of this constitution which i do not at present approve, but i am not sure i shall never approve them: for having lived long, i have experienced many instances of being obliged by better information or fuller consideration, to change opinions even on important subjects, which i once thought right, but found to be otherwise. it is therefore that the older i grow, the more apt i am to doubt my own judgment, and to pay more respect to the judgment of others.