Explain why metals have high melting points and can conduct electricity.

AQA GCSE Chemistry (8462) — 4.2.2 How bonding and structure are related to the properties of substances · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Metals such as copper are used in electrical wiring and in high-temperature industrial equipment.

Model answer (4 marks)

Metals contain delocalised electrons that are free to move through the crystal lattice.
These delocalised electrons can carry electrical charge, allowing the metal to conduct electricity.
The positive metal ions are held together by strong metallic bonds with the delocalised electrons.
A large amount of energy is required to break these strong bonds, giving metals high melting points.

Examiner tips

  • Use the term "delocalised electrons" and "metallic bonds". Show the link between free electrons and electrical conductivity. Explain that breaking metallic bonds needs high energy → high melting point.
  • common_mistakes
  • :
  • Failing to mention delocalised electrons. Confusing metallic bonds with ionic or covalent bonds. Giving a generic statement about metals without linking to conductivity or melting point.

Mark scheme (4 marks)

  1. Metals contain delocalised electrons (that are free to move through the structure)
  2. The delocalised electrons can carry electrical charge / current through the metal
  3. There are strong metallic bonds between the positive ions and the delocalised electrons
  4. A large amount of energy is needed to break these strong bonds, so the melting point is high

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