What is considered a good conductor of electricity?

Copper is considered a good conductor of electricity because it has a high number of free electrons that can move easily through the metal, allowing electrical current to flow with minimal resistance. This property makes copper an ideal choice for electrical wiring and components, as it can efficiently carry electrical currents with low energy loss.

In contrast, sodium is a metal but is less commonly used as a conductor for electrical wiring due to its reactivity and the fact that it must be in a molten state to conduct electricity effectively. Glass and wood, on the other hand, are considered insulators, meaning they do not conduct electricity well. They lack free-moving electrons, making them appropriate materials for preventing the flow of electrical current.