Apply the shared-electron-pair model to a nitrogen molecule, N2\mathrm{N_2}N2.
Each nitrogen atom has five outer-shell electrons. In this molecule each atom has a complete outer shell of eight electrons. Both atoms contribute equally to every shared pair.
Deduce how many pairs of electrons must be shared between the atoms. Explain your reasoning using the number of extra electrons each atom needs access to.
Draw a complete outer-shell dot-and-cross diagram of the molecule. Use dots for one nitrogen atom's electrons and crosses for the other atom's electrons.
A bond containing three shared pairs is called a triple covalent bond. Compare the number of bonding electrons and lone pairs in N2\mathrm{N_2}N2 with those in O2\mathrm{O_2}O2. Each oxygen atom has six outer-shell electrons and the oxygen molecule contains a double bond.
53 exam-style questions on Edexcel GCSE Chemistry 2.4 Covalent bonding, covering 2.4.1 Covalent bonding and simple molecules. Each one has a worked solution and a mark scheme showing where the marks go.