how do ionic radii vary within a group of metals .How do they vary within a group of nonmetals

Expert Answers
jerichorayel eNotes educator| Certified Educator


The general rule for the ionic radii of metals and non metals are as follows:

Ionic Metals: ionic radii increases from right to left 

meaning, Na+> Mg2+> Al3+


Ionic non metals: ionic radii increases from righ to left

meaning, P^-3 > S^-2 > Cl^-1



comparing the ions with its atomic form

For metals: the ion form of metals tend to have smaller radius that its atomic/uncharged state. Take a look at the sodium and sodium ion for example:

Na and Na+

Na> Na+


For non-metals: the ion of a non metals is larger than its atomic/ uncharged state. For example:

Cl and Cl-




hope this helps :)