Why are lithium salts commonly hydrated and those of the other alkali ions usually anhydrous?

Explanation

Lithium is the smallest in size among the alkali metals. Hence `Li^(+)` ion can polarize water molecules more easily than alkali metals. As a result, water molecules get attached to lithium salts as water of crystallization Hence, lithium salts such as trihydrated lithium chloride `(LiCl. 3H_(2)O)` are commonly hydrated As the size of the ions increases, their polarizing power decreases Hence, other alkali metal ions usually form anhydrous salts.