Why does the solubility of alkaline earth metal carbonates and sulphates in water decrease down the group ?

Explanation

The size of `CO_(3)^(2-)` and `SO_(4)^(-)` ions are much bigger than those of the cations. Therefore the lattice energies of carbonates and sulphates Tema s constant as we move down the group. Since the hydration enthalpies decrease as the size of the cation increases down the group, the solubility of carbonates and sulphates of alkaline earth metals decrease down the group.