• Covalent bonding can produce substances that have different structures and therefore different physical properties.
  • We have already seen how small molecules such as H2O and N2 are simple, covalent compounds.
  • These simple compounds consist of molecules which contain fixed numbers of atoms joined together covalently.
  • Giant covalent structures have a huge number of non-metal atoms bonded to other non-metal atoms via strong covalent bonds.
  • Three common macromolecules are diamond, graphite and silicon dioxide.


  • They have high melting and boiling points as they have many strong covalent bonds.
  • Large amounts of heat energy are needed to overcome these forces and break down bonds.
  • Most cannot conduct electricity as they do not have free electrons nor charged particles but there are some exceptions such as graphite.

AQA GCSE Chemistry Notes

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Morgan Curtin Chemistry

Author: Morgan

Morgan’s passion for the Periodic Table begun on his 10th birthday when he received his first Chemistry set. After studying the subject at university he went on to become a fully fledged Chemistry teacher, and now works in an international school in Madrid! In his spare time he helps create our fantastic resources to help you ace your exams.