Copper (29)

Copper is one of the most important metals. Copper is reddish with a bright metallic luster. It is malleable, ductile, and a good conductor of heat and electricity (second only to silver in electrical conductivity). Its alloys, brass and bronze, are very important. Monel and gun metals also contain copper. Apparently the reason that policemen in the USA are nicknamed "cops" or "coppers" is to do with their uniforms which used to have copper buttons.

The most important compounds are the oxide and the sulphate, (blue vitriol).

•Name: Copper
•Symbol: Cu
•Atomic number: 29
•Atomic weight: 63.546
•Standard state: solid at 298 K
•CAS Registry ID: 7440-50-8
•Group in periodic table: 11
•Group name: Coinage metal
•Period in periodic table: 4
•Block in periodic table: d-block
•Color: copper, metallic
•Classification: Metallic

Historical information

Copper was discovered by Known since ancient times at no data in not known. Origin of name is from the Latin word "cuprum" meaning the island of "Cyprus". The discovery of copper dates from prehistoric times. There are reports of copper beads dating back to 9000BC found in Iraq. Methods for refining copper from its ores were discovered around 5000BC and a 1000 or so years later it was being used in pottery in North Africa.

Part of the reason for it being used so early is simply that it is relatively easy to shape. However it is somewhat too soft for many tools and around 5000 years ago it was discovered that when copper is mixed with other metals the resulting alloys are harder than the copper itself. As examples, brass is a mixture of copper and zinc while bronze is a mixture of copper and tin.

Copper is one of the elements which has an alchemical symbol, what looks like the symbol for female.

Sometime prior to the autumn of 1803, the Englishman John Dalton was able to explain the results of some of his studies by assuming that matter is composed of atoms and that all samples of any given compound consist of the same combination of these atoms. Dalton also noted that in series of compounds, the ratios of the masses of the second element that combine with a given weight of the first element can be reduced to small whole numbers (the law of multiple proportions). This was further evidence for atoms. Dalton's theory of atoms was published by Thomas Thomson in the 3rd edition of his System of Chemistry in 1807 and in a paper about strontium oxalates published in the Philosophical Transactions. Dalton published these ideas himself in the following year in the New System of Chemical Philosophy.

Physical properties

•Melting point: 1357.77 [or 1084.62 °C (1984.32 °F)] K
•Boiling point: 3200 [or 2927 °C (5301 °F)] K
•Density of solid: 8920 kg m-3

Orbital properties

•Ground state electron configuration: [Ar].3d10.4s1
•Shell structure: 2.8.18.1
•Term symbol: 2S1/2

Isolation

Copper metal is readily available commercially so it is not normally necessary to make it in the laboratory. Most copper production is based upon sulfide ores containing little copper but quite a lot of iron. New cleaner technologies are now important but older processes present major environmental problems. Complex procedures are used initially to form a form of copper sulfide appropriate for final reduction via a copper(I) oxide. The resulting crude copper is purified using an electrolytic procedure involving plating onto pure copper cathodes.

2Cu2S + 3O2 → 2Cu2O + 2SO2

2Cu2O + Cu2S → 6Cu + SO2

Notably, the purification step leaves an "anode slime" which contains useful amounts of silver and gold.