Copper

Source of the photo
http://webmineral.com/specimens/picshow.php?id=280
Author of the description
Gruiz Katalin

Atomic number

29

Atomic mass

63.546 g.mol -1

Electronegativity

1.9

Density

8.9 g.cm-3 at 20°C

Melting point

1083 °C

Boiling point

2595 °C

Vanderwaals radius

0.128 nm

Ionic radius

0.096 nm (+1) ; 0.069 nm (+3)

Isotopes

6

Electronic shell

[ Ar ] 3d10 4s1

Energy of first ionisation

743.5 kJ.mol -1

Energy of second ionisation

1946 kJ.mol -1

Standard potential

+ 0.522 V ( Cu+/ Cu ) ; + 0.345 V (Cu2+/ Cu )

Discovered by

The ancients

 

Copper is a reddish metal with a face-centered cubic crystalline structure. It reflects red and orange light and absorbs other frequencies in the visible spectrum, due to its band structure, so it as a nice reddish colour. It is malleable, ductile, and an extremely good conductor of both heat and electricity. It is softer than iron but harder than zinc and can be polished to a bright finish. It is found in group Ib of the periodic table, together with silver and gold. Copper has low chemical reactivity. In moist air it slowly forms a greenish surface film called patina; this coating protects the metal from further attack.

Applications

Most copper is used for electrical equipment (60%); construction, such as roofing and plumbing (20%); industrial machineri, such as heat exchangers (15%) and alloys (5%). The main long established copper alloys are bronze, brass (a copper-zinc alloy), copper-tin-zinc, which was strong enough to make guns and cannons, and was known as gun metal, copper and nichel, known as cupronickel, which was the preferred metal for low-denomination coins.
Copper is ideal for electrical wiring because it is easily worked, can be drawn into fine wire and has a high electrical conductivity.