Explain why metals have high melting points and are good conductors of electricity.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Metals are widely used in construction and electrical wiring due to their physical properties. These properties can be explained by metallic bonding.
Model answer (5 marks)
In metallic bonding the metal atoms lose their outer electrons to form positive ions (cations). A sea of delocalised electrons surrounds the positive ions. The strong electrostatic attraction between the positive ions and the delocalised electrons holds the structure together. A large amount of energy is required to break these strong electrostatic attractions, which explains the high melting point. The delocalised electrons can move freely through the structure and carry charge, which explains why metals are good conductors of electricity.
Examiner tips
- Use the term ‘delocalised electrons’ and ‘positive ions’ to show understanding of the structure.
- Explain that the high melting point is due to the strong ion–electron attraction.
- Show that electrical conductivity comes from the mobility of the delocalised electrons.
- Keep the answer concise and directly linked to the points in the mark scheme.
Common mistakes
- Confusing metallic bonding with ionic bonding and not mentioning delocalised electrons.
- Failing to link the high melting point to the strength of the electrostatic attraction.
- Using vague terms such as ‘strong bonds’ without specifying ion–electron attraction.
Mark scheme (5 marks)
- In metallic bonding, metal atoms lose their outer electrons to form positive ions (cations)
- A 'sea' of delocalised electrons surrounds the positive ions
- Strong electrostatic attraction between the positive ions and the delocalised electrons holds the structure together
- A large amount of energy is needed to break these strong electrostatic attractions, explaining the high melting point
- The delocalised electrons can move freely through the structure and carry charge, explaining electrical conductivity
Related
- All Edexcel A-Level Chemistry (9CH0) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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