What is the thermal stability of Group 2 carbonates and how does it relate to reactivity?

Group 2 carbonates become less thermally stable down the group, which increases their reactivity.

Group 2 carbonates, including calcium carbonate, magnesium carbonate, and barium carbonate, are generally stable compounds. However, their thermal stability decreases as you move down the group. This means that the carbonates become more reactive as you move down the group.

For example, calcium carbonate is relatively stable and requires a high temperature to decompose. On the other hand, barium carbonate is much less stable and can decompose at a lower temperature. This is because the size of the Group 2 metal cation increases down the group, which weakens the bond between the metal cation and the carbonate ion.

The decreased thermal stability of Group 2 carbonates down the group also affects their solubility in water. As the carbonates become more reactive, they are more likely to react with water to form metal hydroxides and carbon dioxide. This means that the solubility of Group 2 carbonates increases down the group.

In summary, the thermal stability of Group 2 carbonates decreases down the group, making them more reactive. This reactivity is due to the weakening of the bond between the metal cation and the carbonate ion, which also affects their solubility in water.