Why do some metals conduct electricity better than others?

Metal atoms share a sea of delocalized electrons, which allows electric charge to flow. The exact arrangement of atoms, impurities, temperature, and crystal defects affect how easily electrons move. Silver is the best electrical conductor of the common metals, followed closely by copper and gold; copper is used most widely because it is cheaper than silver. Heating a metal usually makes it conduct less efficiently because atomic vibrations scatter electrons. This is why transmission lines, wiring, and circuit traces rely heavily on copper and aluminum.