Hi, How would you determine the relative atomic sizes of a neutral atom and an ion? I can't figure this out. It can't be that all neutral atoms are always smaller than all ions can it? For example, how would I determine if Cl- is smaller or larger than S?. (The answer is that Cl- is larger than S). Is there a rule that applies to all comparisons of neutral atoms and ions? For example, how would I determine if Na is smaller or larger than Cl-? Thank you very much!