Copper
Symbol: Cu
Atomic Number: 29
Atomic Mass: 63.546 amu (atomic mass units)
Melting Point: 1083.0 C (1356.15 K, 1981.4 F)
Boiling Point: 2567.0 C (2840.15 K, 4652.6 F)
Number of Protons: 29
Number of Electrons: 29
Number of Neutrons: 35
Classification: Transition Metal
Crystal Structure: Cubic
Density @ 293 K: 8.96 grams per cubic centimeter
Color: red/orange
Archaeological evidence points to copper being used by man 11000 years ago. This was probably obtained as native copper which is the element found in its free state. Extraction of copper from its mineral ores was being carried out at least 7000 years ago. Copper is a fairly soft metal and unsuitable for use in tools or weapons. 5000 ago man started producing the first alloys when production of bronze began. Bronze is an alloy of copper and tin and is much more suitable for tool making than copper alone. The Romans got much of their copper from the island of Cyprus. The Latin word “cuprum” from which the element gets its name means “from the island of Cyprus”.
Copper is a malleable and ductile metal. It is a good conductor of both heat and electricity. Silver is the only metal better at conducting electricity.
Copper is a biologically essential element in small quantities. It is found in some enzymes and in hemocyanin.
Naturally occurring copper has two isotopes both of which are stable. Copper-63 is the most common at 69.17%. The remaining 30.83 % consists of copper-65. The mass numbers of the unstable isotopes of copper are in the range of 52 to 80.
Although copper is found free in nature most copper is extracted commercially from a number of mineral ores. The principal copper ores are cuprite, tenorite, malachite, chalcocite, covellite and bornite. Large deposits of copper ore are found in many countries including the USA, Canada, Chile and Zambia.
Copper metal has a number of important industrial uses. The main use for copper is as wire in electrical equipment and distribution networks. It is also used to make water pipes. It has been widely used to make coins the American penny used to be made of copper but now they are made of zinc and coated with copper. Some jewelry is made of copper.
Alloys of copper combine copper resistance to corrosion with another metals hardness. Bronze containing up to 25% zinc is often used by sculpture artists to cast their works of art. Brass is an alloy which contains between 5% and 45 % zinc. Brass was first made over 2500 year ago and the Romans made extensive use of this alloy. Today brass is used to make screws, musical instruments and numerous ornaments. Other alloys containing copper include gun metal and monel.
Of the many copper compounds used today hydrated copper sulfate (CuSO4.H2O) has the widest usage. It is used as an herbicide in agriculture and an algaecide in the water industry. It also provides a blue color for inks. Cupric chloride (CuCl3) is used in the textile industry to fix dyes to fabrics. The toxic compound cuprous chloride (CuCl) is used to absorb carbon dioxide. Electroplating makes use of copper cyanide (CuCN).
