Copper

Atomic Number:

29

Melting Point: 1084.6 ºC
Atomic Symbol: Cu Boiling Point:  2562 ºC
Atomic Weight: 63.546 amu Density: 8920 kg/m 3
Atomic Radius:

127.8 pm

Oxidation States: 2, 1
Covalent Radius: 138 pm Electron Configuration: [Ar]4s13d10
van der Waals Radius:

140 pm

State of Matter: solid 

History

(Latin cuprum , from the island of Cyprus) It is believed that copper has been mined for 5,000 years.

Properties

Copper is reddish and takes on a bright metallic luster. It is malleable, ductile, and a good conductor of heat and electricity (second only to silver in electrical conductivity).

There are numerous alloys of copper - speculum metal is a copper/tin alloy, Brass is a copper/zinc alloy, and bronze is a copper/tin alloy. Common oxidation states of copper include the copper (I) state, Cu+1, and copper (II) state, Cu+2.

Sources

Copper occasionally occurs natively, and is found in many minerals such as cuprite, malachite, azurite, chalcopyrite, and bornite.

Large copper ore deposits are found in the U.S., Chile, Zambia, Zaire, Peru, and Canada. The most important copper ores are the sulfides, the oxides, and carbonates. From these, copper is obtained by smelting, leaching, and by electrolysis.

Uses

The electrical industry is one of the greatest users of copper. Iron's alloys -- brass and bronze -- are very important: all American coins are copper alloys and gun metals also contain copper.

Copper has wide use as an agricultural poison and as an algaecide in water purification. Copper compounds, such as Fehling's solution, are widely used in analytical chemistry tests for sugar. Copper carbonate is green from which arises the unique appearance of copper-clad roofs or domes on some buildings. Copper oxides form the basis of many unconventional superconductors.

Isotopes

There are two stable isotopes, 63Cu and 65Cu, along with a couple dozen radioisotopes. The vast majority of radioisotopes have half lives on the order of minutes or less, the longest lived, 64Cu, has a half life of 12.7 hours, with two decay modes, leading to two separate products.

Hazards

All copper compounds, unless otherwise known, should be treated as if they were toxic. The metal, when powdered, is a fire hazard. 30g of copper sulfate is potentially lethal in humans. Copper in drinking water at concentrations higher than 1 mg/liter can stain clothes and items washed in water. The suggested safe level of copper in drinking water for humans varies depending on the source, but tends to be pegged at 1.5 to 2 mg/liter.