Question

Explain why are cation smaller and anions larger in radii than their parent atoms.

Answer 1

this is because cation losses its electron and losses their one valence shell therefore are smaller than its parent
and anions gains electron and are larger than its parent atom.
eg.. Ca²+ is smaller than Ca
and
Cl- is larger than Cl.

Answer 2

this is because a cation loses electrons.... thus the no of shells decreases, thereby reducing the radius.
in anion, it gains electrons.... thus no of shells increases thereby increasing the radius