Question

Why are lithium saltscommonly hydrated and those of the other alkali metal ions usuallyanhydrous?

Answer 1

Lithium is the smallestin size among the alkali metals. Hence, Li⁺ ion canpolarize water molecules more easily than other alkali metals. As aresult, water molecules get attached to lithium salts as water ofcrystallization. Hence, lithium salts such as trihydrated lithiumchloride (LiCl.3H₂O) are commonly hydrated. As the size ofthe ions increases, their polarizing power decreases. Hence, otheralkali metal ions usually form anhydrous salts.