Question

Why cation are smaller and anion larger in radii than their parents?

Answer 1

In case of cations they have comparatively less electrons than their parent atoms keeping the nuclear charge same.. therefore electrons held more tightly by the protons and the atomic radii become smaller....
in case of anions they have comparatively more atoms than their parent atoms keeping the nuclear charge same ...therefore electrons are held more loosely n the atomic radii become larger than the parent atoms...


hope it helps.. :)