150px-Native Copper from the Keweenaw Peninsula Michigan

A chunk of copper mined from the Keweenaw Peninsula, Michigan

Atomic Properties

Copper is a chemical element with symbol Cu and with the atomic number 29, meaning it has 29 protons and 29 electrons. It has a mass number of 64,[1] giving a copper atom 35 neutrons. Copper gets its name from the original Latin form of "metal of Cyprus".[2]


Copper is a soft, malleable, and ductile metal with very high thermal and electrical conductivity, thus giving copper its purpose in electrical wires and as a heat conductor. A freshly exposed surface of pure copper has a reddish-orange color.

Copper is one of the few transition metals that occur in nature in a directly usable form (native metals) as opposed to metals needing extraction from an ore.

Chemical Reactions

Copper reacts with oxygen to form copper oxide, which is the green substance that forms on copper coins. The Statue of Liberty was supposed to be brown like copper, but due to copper reacting with oxygen forming copper oxide, the statue now looks green. Copper Sulphate (originally called "blue vitriol") is a blue salt used in many chemistry experiments.


Copper forms several alloys. Copper is mixed with tin to form the alloy bronze, and with zinc to form the alloy brass.


  2. Encyclopaedia Britannica, 11th ed., vol. 7, p. 102