How can you tell if a element is an isotope, ion, or stable?

An isotope is an element that has a different number of neutrons than the stable form. An ion is an atom that has a charge; this means it has lost or gain an electron(s). A stable form of an element will be uncharged and has the number of neutrons which can be inferred from the recorded mass value in the periodic table. For example, Carbon has the recorded atomic mass of 12.01 and has 6 protons. 12.01-6=6.01 so we can tell that the most stable form of carbon would have 6 neutrons. (The mass number is an average of all naturally occurring isotopes and there are a few isotopes that have 7 neutrons which is why the mass number is not exactly 12)

The question is either incomplete or just does not make sense.

Perhaps you should mention some specific examples that could be explained.