Question

Explain why cations are smaller and anions are larger in size than their parent atom.

Answer 1

cation has more protons than electrons. so its nucleus can attract more forcefully and it leads to decrease the size.

anion has less protons than electrons. so its nucleus attract comparetively less .so it has larger size

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