Which statement describes the primary reason why metals are much better conductors of thermal energy than non-metal solids?
Metal atoms can detach and flow freely from the hot end to the cold end.
Metals contain delocalised (free) electrons that can move rapidly through the lattice to transfer energy.
The intermolecular forces in metals are extremely weak, allowing molecules to vibrate more easily.
Metals are less dense than non-metals, which allows thermal energy to disperse more quickly.
301 exam-style questions on CIE IGCSE Physics 2.3 Transfer of thermal energy, covering 2.3.1a Thermal conductors and thermal insulators, 2.3.1b Explaining thermal conduction, 2.3.2 Convection, 2.3.3a Thermal radiation, 2.3.3b Surface colour and texture, 2.3.3c Rate of emission and absorption of radiation, and 2.3.4 Consequences of thermal energy transfer. Each one has a worked solution and a mark scheme showing where the marks go.