# Explain why sodium chloride has a high melting point but does not conduct electricity when solid. Include in your answer what happens when sodium chloride is melted.

> AQA A-Level Chemistry (7405) — 3.1.3 Bonding · Explain · 5 marks

> Sodium chloride is an ionic compound made up of sodium ions and chloride ions arranged in a giant ionic lattice.

## Mark scheme (5 marks)

1. Sodium chloride has a giant ionic lattice structure
2. There are strong electrostatic forces of attraction between oppositely charged ions
3. A large amount of energy is needed to overcome these forces, so the melting point is high
4. When solid, the ions are held in fixed positions and cannot move
5. When melted, the ions are free to move and carry charge, so it conducts electricity

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