Sample of native elemental copper Cu rotating. Copper has the atomic number 29, and is a soft, ductile transition metal that is an excellent conductor of heat and electricity. It is one of only a few metals to occur in nature in an elemental native form. It is more often found combined with other elements, such as with oxygen in the form of copper oxide. As it is found in a native state, it has a long history of use, and evidence of its use goes back more than 10,000 years. It is still widely used today, in electrical wiring, and in alloys such as brass and bronze.