Mass numbers are used to identify different isotopes of an element and are a count of the protons and neutrons found in that isotope's nucleus. Interestingly, the number of protons will remain constant, regardless of the isotope, but the number of neutrons will change. This is because an ato...
8,1 87Francium2,8,18,32,18,8,1 All of the atoms in alkali metals have one electron in their outer electron shells. To become stable they have to give off one electron to elements with seven electrons in their outer