How does the ionic radius of a typical anion compare?

1 Answer
Aug 2, 2017

Compared to what, the parent atom?


Well the radius of an anion SHOULD be greater than that of the parent atom. Why? Two factors are important here: (i) nuclear charge; and (ii) shielding by other electrons. These work in opposition; high nuclear charge reduces atomic size inasmuch as it attract the valence electrons; full electronic shells shield the nuclear charge, and force the valence electrons to lie at a greater separation, i.e. a greater radius, from the nuclear core.