Question

The correct order of size of hydrated ions among the following is

• A. $L{i}^{+}>N{a}^{+}>K^{+}$
• B. $N{a}^{+}>L{i}^{+}>K+$
• C. $K^{+}>N{a}^{+}>L{i}^{+}$
• D. cannot predict

Answer 1

The correct option is A $L{i}^{+}>N{a}^{+}>K^{+}$

Smaller size of the ion, greater the extent of hydration and greater the size of the hydrated ion.
As we move down the group, size of the ion increases, and hence extention of hydration decreases and hence the size of the hydrated ion decreases.