Copper has 29 protons and 29 electrons, corresponding to its atomic number of 29 on the periodic table. Copper also has 35 neutrons. It has an atomic mass of 63.546 atomic mass units and is grouped in the transition metals. Several isotopes of copper exist with varying half-lives.
Copper has been mined for several thousand years. It is reddish in color, ductile and malleable. It is a good conductor of heat and electricity, second to silver as the best conductor of electricity. Because of its conducting properties, it is used in the electrical industry. It is also used in plumbing, cookware and coinage.