Copper is a metal used in electrical wiring and water pipes. It is malleable, has a high melting point, and conducts electricity well. Explain these three properties of copper in terms of metallic bonding.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Copper has been used in plumbing and electrical systems for centuries. It can be bent and shaped without breaking, withstands high temperatures, and allows electric current to pass through it easily.
Model answer (5 marks)
In metallic bonding the metal atoms lose their outer electrons, forming a lattice of positive ions surrounded by a sea of delocalised electrons.
Copper’s high melting point is due to the strong electrostatic attraction between the positive Cu⁺ ions and the delocalised electrons; a large amount of energy is required to break these forces, so the melting point is high.
Copper conducts electricity because the delocalised electrons are free to move through the lattice and carry charge.
Copper is malleable because the layers of positive ions can slide over one another while the sea of delocalised electrons continues to bind the lattice together.
Copper’s high melting point is due to the strong electrostatic attraction between the positive Cu⁺ ions and the delocalised electrons; a large amount of energy is required to break these forces, so the melting point is high.
Copper conducts electricity because the delocalised electrons are free to move through the lattice and carry charge.
Copper is malleable because the layers of positive ions can slide over one another while the sea of delocalised electrons continues to bind the lattice together.
Examiner tips
- Use the phrase "delocalised electrons" and "lattice of positive ions". Explain that melting point relates to energy needed to break electrostatic forces. Show that conductivity comes from free electrons. Mention ion layers sliding for malleability.
Common mistakes
- Confusing the role of electrons with that of ions. Forgetting to link high melting point to strong electrostatic forces. Saying the metal is malleable because it is soft rather than because ion layers slide.
Mark scheme (5 marks)
- In metallic bonding, metal atoms lose their outer electrons to form a lattice of positive ions surrounded by a 'sea' of delocalised electrons.
- Copper has a high melting point because there are strong electrostatic forces of attraction between the positive ions and the delocalised electrons.
- A large amount of energy is needed to break these strong electrostatic forces, so the melting point is high.
- Copper conducts electricity because the delocalised electrons are free to move through the lattice and carry charge.
- Copper is malleable because the layers of positive ions can slide over each other whilst the sea of delocalised electrons maintains the metallic bonding.
Key terms in this question
Related
- All Edexcel A-Level Chemistry (9CH0) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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