Why are metals good conductors?
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Answer: Free electrons carry electricity
Metals are very dense materials — Wrong. Density doesn't determine conductivity. Metals conduct because they have free electrons—in metallic bonds, outer electrons aren't bound to specific atoms but move freely. These mobile electrons carry electric current efficiently. Some dense materials (like lead) conduct poorly; some light metals (like aluminum) conduct well.
Free electrons carry electricity ✓ — Correct! Metallic bonds create a 'sea' of free electrons—outer electrons aren't bound to specific atoms but move freely throughout the metal. When voltage is applied, these mobile electrons drift, carrying electric current. This electron mobility makes metals excellent conductors of electricity (and heat). Copper and silver have particularly mobile electrons, making them the best conductors.
Metal atoms touch each other — Wrong. Atoms touching doesn't create conductivity—many solids have atoms in contact. Metals conduct because metallic bonds create free electrons that can move throughout the material, carrying current. It's electron mobility, not atom proximity, that creates conductivity.