Copper is a metal element and a transition element. Its chemical symbol is Cu, English copper, and its atomic number is 29. Pure copper is a soft metal, the surface is reddish orange with metallic luster when it is just cut open, and its simple substance is purple-red. Good ductility, high thermal conductivity and electrical conductivity, so it is the most commonly used material in cables and electrical and electronic components. It can also be used as a building material and can be composed of many alloys.