Nitrates of alkali metals, except LiNO3, decompose on strong heating to form nitrites.
LiNO3, on decomposition, gives oxide.
Similar to lithium nitrate, alkaline earth metal nitrates also decompose to give oxides.
As we move down group 1 and group 2, the thermal stability of nitrate increases.
Nitrates of both group 1 and group 2 metals are soluble in water.
The carbonates of alkali metals are stable towards heat. However, carbonate of lithium, when heated, decomposes to form lithium oxide. The carbonates of alkaline earth metals also decompose on heating to form oxide and carbon dioxide.
Carbonates of alkali metals are soluble in water with the exception of Li2CO3. Also, the solubility increases as we move down the group.
Carbonates of alkaline earth metals are insoluble in water.
Sulphates of both group 1 and group 2 metals are stable towards heat.
Sulphates of alkali metals are soluble in water. However, sulphates of alkaline earth metals show varied trends.
BeSO4 Fairly soluble
CaSO4 Sparingly soluble
In other words, while moving down the alkaline earth metals, the solubility of their sulphates decreases.