(a)[1]
On strong heating, copper(II) carbonate decomposes in a way similar to Group 2 carbonates. Predict what would be seen when anhydrous copper(II) carbonate is heated.
(b)[3]
Describe and explain how the thermal stability of the Group 2 carbonates changes down the group.
(c(i))[2]
Calcium cyanamide, $\text{CaCN}_2$, can be used as a fertiliser. Complete the dot-and-cross diagram for the cyanamide ion, $\text{CN}_2^{2-}$. Use the key below for the electrons: electrons from carbon, electrons from nitrogen, added electron(s) causing the overall negative charge.
(c(ii))[2]
$\text{CaCN}_2$ reacts readily with water to produce only ammonia and an insoluble white solid. Suggest an equation for this reaction.