Explain why metals are good conductors of heat.
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 lattice.
When one end of a metal is heated, these delocalised electrons gain kinetic energy.
The energised electrons then move rapidly through the metal, carrying the energy with them.
Because the electrons can move freely in all directions, the heat is transferred quickly throughout the metal.
When one end of a metal is heated, these delocalised electrons gain kinetic energy.
The energised electrons then move rapidly through the metal, carrying the energy with them.
Because the electrons can move freely in all directions, the heat is transferred quickly throughout the metal.
Examiner tips
- Use the term "delocalised electrons". Explain the energy transfer step by step. Show the link between electron mobility and rapid heat conduction.
- common_mistakes
- :
- Forgetting to mention delocalised electrons. Confusing electron movement with ion movement. Saying only the lattice vibrates without linking to electrons.
Mark scheme (4 marks)
- Metals contain delocalised electrons (free/mobile electrons)
- When one end of the metal is heated, these delocalised electrons gain (kinetic) energy
- The energised delocalised electrons move/travel through the metal (transferring energy)
- Energy is transferred rapidly throughout the metal because electrons can move freely in all directions
Related
- All Cambridge International IGCSE Chemistry (0620) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →