There is no metal that does not conduct electricity entirely, but there are some metals that are less effective conductors than others. Metal atoms have electrons in their outer shells that are not tied to any particular atom and can flow freely within the metal when electricity is applied.
The most effective conductor of electricity is pure gold, closely followed by pure copper and pure silver. The worst conductors of electricity among metals are carbonized steel, pure lead and stainless steel. The best insulators, or non-conductors, are covalent and ionic solids, which do not contain the free-flowing electrons found in metals.