All the carbonates in this group undergo thermal decomposition to the metal oxide and carbon dioxide gas. The term "thermal decomposition" describes splitting up a compound by heating it.
All the Group 2 carbonates and their resulting oxides exist as white solids. If "X" represents any one of the elements, the following describes this decomposition:XCO3(s)→XO(s)+CO2(g)XCO3(s)→XO(s)+CO2(g)
Down the group, the carbonates require more heating to decompose.
The carbonates become more thermally stable down the group.
Group 2 oxides:
These react with water to form metal hydroxide.
These are soluble so dissolve in the water forming an alkali, pH10 - 12