Question

The charge/size ratio of a cation determines its polarizing power. Which one of the following sequences represents the increasing order of the polarizing power of the cationic species, $K^{+},C{a}^{2+},M{g}^{2+},B{e}^{2+}$

• A. $K^{+}>C{a}^{2+}>M{g}^{2+}<B{e}^{2+}$
• B. $B{e}^{2+}<C{a}^{2+}<M{g}^{2+}<K^{+}$
• C. $M{g}^{2+}<K^{+}<B{e}^{2+}<C{a}^{2+}$
• D. $K^{+}<C{a}^{2+}<M{g}^{2+}<B{e}^{2+}$

Answer 1

The correct option is D $K^{+}<C{a}^{2+}<M{g}^{2+}<B{e}^{2+}$

Smaller the size and higher the charge, more will be polarizing power of the cation. Since the order of the size of cation is $K^{+}>C{a}^{2+}>M{g}^{2+}>B{e}^{2+}$ the correct order of polarizing power is $K^{+}<C{a}^{2+}<M{g}^{2+}<B{e}^{2+}$.