Copper metal (Cu). Atomic weight 63.546. Atomic number 29. Copper is a chemical element. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. From 10000 BCE this metal has be used pure and later as a constituent of bronze, brass and other alloys. It can be found in nature in a usable metallic form. Copper reacts with oxygen and sulphur while old roofs and statues turn green with verdigris (copper carbonate).