Discuss the trend of the following:
(i) Thermal stability of carbonates of Group 2 elements.
(ii) The solubility and the nature of oxides of Group 2 elements
(i) Thermal stability increases down the group.
(ii) All oxides are basic and ionic in nature except BeO, which is amphoteric and covalent. The lattice energy of oxides decreases with an increase in the size of cation. Basic nature also increases down the group. Except for BeO and MgO, all are soluble in water and produce a large amount of heat on dissolving. The insolubility of BeO and MgO can be attributed to their high lattice energy.