Metals are described as malleable and good conductors of electricity. Explain why metals have these two properties, in terms of their structure and bonding.

Eduqas GCSE Chemistry — C2 Bonding, structure and properties · 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 have a crystalline lattice in which atoms are arranged in layers that can slide over one another.

The ability of these layers to move relative to each other allows a metal to be hammered or rolled into sheets – this is the origin of malleability.

Metals also possess a sea of delocalised valence electrons that are not attached to any particular atom.

These free electrons can move easily through the lattice, carrying charge when a potential difference is applied, which makes metals good conductors of electricity.

Examiner tips

  • Use the phrase ‘delocalised electrons’ and ‘sea of electrons’ to show understanding of metallic bonding.
  • Explain that layer sliding gives malleability and electron mobility gives conductivity – link structure to property directly.

Common mistakes

  • Confusing metallic bonding with covalent or ionic bonding; not mentioning delocalised electrons.
  • Failing to connect the sliding layers explicitly to malleability or the electron movement to conductivity.

Mark scheme (4 marks)

  1. Metals contain layers of atoms that can slide over each other
  2. This (sliding of layers) is why metals are malleable / can be bent and shaped
  3. Metals contain delocalised electrons that are free to move throughout the structure
  4. The movement of delocalised electrons carries electrical charge / current through the metal

Key terms in this question

malleable · conductor

Related

More Bonding, structure and properties questions

▶ Try answering this question with AI marking (free) →