Question

lithium salta are commonly hydrated and those of other alkali ions are usually anhydrous.

Answer 1

Lithium is the smallest in size among all the elements of the alkali metals group. Hence, Lithium ion can polarize water molecules more easily than other alkali metals. As a result of this ability to polarize water, water molecules get attached to lithium salts as water of crystallization. Hence, lithium salts are commonly hydrated. As the size of the ions increases, their polarizing power decreases. Hence, other alkali metal ions usually form anhydrous salts.