Question

Why cations are smaller and anions are larger in radius than their parent atoms

Answer 1

because cation means loosing of electrons so it means like positive charge only no......... and anion means gaining of electrons that it is like negative charge no....... so cations are and anions are larger in radius than their parent atom 

Answer 2

Answer:

(1) An anion is formed by the acceptance of an electron by a parent atom.

A + e^- → A^-

(2) The nuclear charge in a parent atom and its anion is same.

(3) The additional electron in an anion, results in the repulsion among the electrons and results in the decrease in effective nuclear charge, as compared to the parent atom. Therefore, the radius of an anion is larger than its parent atom. For example, F atom has atomic radius 64 pm while anion F has ionic radius 136 pm