- All organic molecules contain carbon; this is due to its chemical properties that allow it to produce the individuality of living things.
- A Carbon atom has four electrons in its outer shell, and becomes stable when it loses or gains four electrons.
- This would be too many to lose or gain, as the charge when losing and gaining four electrons would be either 4+ or 4-, which is too highly charged. So carbon forms covalent bonds.
- For example, in methane a carbon atom bonds with four hydrogen atoms, sharing their electrons.
- Carbon can form a strong covalent bond with itself (catenation) and so can form long chains. This leads to a limitless variety of carbon compounds.
- Hydrocarbons are compounds containing Hydrogen and Carbon only.
- There three different categories of Hydrocarbon: alkanes, alkenes and aromatic hydrocarbons.
- Aromatic hydrocarbons are derived from benzene.
- Aliphatic hydrocarbons have an open chain structure.
Useful books for revision:
Revise AS Chemistry for Salters (Written by experienced examiners and teachers of Salter's chemistry)
Revise AS Chemistry for Salters (OCR) (Salters Advanced Chemistry)