Explain why metals are able to conduct electricity and why they can be bent into different shapes without breaking.

Cambridge International IGCSE Chemistry (0620) — 9.1 Properties of metals · Explain · 4 marks · View as Markdown

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

Model answer (4 marks)

Metals contain delocalised electrons that are free to move throughout the crystal lattice.
These mobile electrons can carry charge, so an electric field causes them to drift and a current flows.
The metal lattice is a regular array of positive ions.
When a force is applied the layers of ions can slide over one another because the metallic bonds are not directional, allowing the metal to be bent without breaking the structure.

Examiner tips

  • Mention delocalised electrons and their role in conductivity. Explain the non‑directional metallic bond and ion‑layer sliding for malleability. Use the exact terms "delocalised electrons" and "regular lattice of positive ions". Keep the answer concise – 4 marks allow a short paragraph.

Common mistakes

  • Confusing conductivity with ionic conduction; forgetting to mention mobile electrons. Describing metals as having covalent bonds or directional bonds. Using vague phrases like "free electrons" without linking to current or lattice structure.

Mark scheme (4 marks)

  1. Metals contain delocalised electrons (free/mobile electrons)
  2. These electrons can move through the metal and carry charge / carry current
  3. Metals have a regular lattice of positive ions
  4. The layers of ions can slide over each other (without disrupting the metallic bonding / without breaking the structure)

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