i. The bicarbonates of the alkaline earth metals do not exist in the solid state but are known only in solution. On heating, these bicarbonates decompose forming carbonates with the evolution of CO2 .
ii. The solubilities of the carbonates decrease as we move down the group from Be to Ba, i.e., BeCO3 > MgCO3 > CaCO3 > SrCO3 > BaCO3 . This is mainly due to the reason that as the size of the cation increases, the lattice enthalpy of their carbonates remains almost unchanged (like that of sulphates) but the enthalpies of hydration of the cations decrease.
iii. The carbonates of all alkaline earth metals decompose on heating to form the corresponding metal oxide and CO2 . The temperature of decomposition of these carbonates, however, increases down the group as the electropositive character of the metal or the basicity of metal hydroxide increases from Be(OH)2 to Ba(OH)2 .
