Question

Metals are good conductors of heat and electricity. Why?

Answer 1

Metal having free electron. When one end of metal wire is heated, these free electron start moving to another end of metal thus conducting heat.

Same for electricity , when potential differences (PD) is applied accrues end of a metallic conductor ,they start moving from negative end to positive end of the conductor giving rise to flow of current which is from positive to negative end. Because of that metal is good conductor of heat and electricity.