Hydrogen cyanide, HCN\mathrm{HCN}HCN, is a simple molecule in which the carbon atom is bonded to both the hydrogen atom and the nitrogen atom. Carbon is in group 4 and nitrogen is in group 5. Every atom has a full outer shell.
Which describes the covalent bonds in a molecule of hydrogen cyanide?
a single H−C\mathrm{H{-}C}H−C bond and a triple C≡N\mathrm{C{\equiv}N}C≡N bond
a single H−C\mathrm{H{-}C}H−C bond and a double C=N\mathrm{C{=}N}C=N bond
a double H=C\mathrm{H{=}C}H=C bond and a double C=N\mathrm{C{=}N}C=N bond
a single H−C\mathrm{H{-}C}H−C bond and a single C−N\mathrm{C{-}N}C−N 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.