(a)[3]
The nitrate ion, $\text{NO}_3^-$, has a dative covalent bond. Finish the following ‘dot-and-cross’ diagram for the bonding in the nitrate ion. Show every outer-shell electron for each of the four atoms. Three electrons have already been shown. Use this code for your electrons: electrons from oxygen, electrons from nitrogen, added electron(s) that produce the overall negative charge.
(b(i))
Write an equation for the effect of heat on magnesium nitrate, $\text{Mg(NO}_3)_2$.
(b(ii))[4]
Describe and explain the pattern seen in the thermal stabilities of the Group II nitrates.
(c)[2]
When concentrated nitric acid, $\text{HNO}_3$, is added to copper turnings, a brown gas is given off. Use data from the Data Booklet to write an ionic equation for this reaction.