Arrange the following sulphates of Alkaline earth metals in order of decreasing thermal stability : BeSO₄, MgSO₄, CaSO₄, SrSO₄

Give reasons of the following:
The crystalline salts of alkaline earth metals contain more water of crystallisation than the corresponding alkali metal salts.

Explain the difference in the nature of bonding in LiF and LiI.

Complete and balance the following reactions:
Ca₅(PO₄)₃F + H₂SO₄ + H₂O $$\buildrel {Heat} \over \longrightarrow $$ ........ + 5CaSO₄.2H₂O + ........