Question

The following is the correct increasing order of the ionic radii

• A. $L{i}^{+}<M{g}^{2+}<K^{+}<A{l}^{3+}$
• B. $A{l}^{3+}<L{i}^{+}<M{g}^{2+}<K^{+}$
• C. $A{l}^{3+}<M{g}^{2+}<K^{+}<L{i}^{+}$
• D. $K^{+}<A{l}^{3+}<M{g}^{2+}<L{i}^{+}$

Answer 1

Answer: (B)

$L{i}^{+}=60pm,K^{+}=133pm,M{g}^{2+}=65pm$,
$A{l}^{3+}=53.5pm$
The correct increasing order of ionic radii is
$A{l}^{3+}<L{i}^{+}<M{g}^{2+}<K^{+}$
In general, on moving from left to right, the ionic radii decreases due to increased effective nuclear charge.
On moving down a group, the number of shells increases and that why ionic radii increase.