Copper is a chemical element with the symbol Cu (from Latin: cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins, and constantan used in strain gauges and thermocouples for temperature measurement.

Copper, ₂₉Cu

Copper
Appearance	Red-orange metallic luster
Standard atomic weight Ar°(Cu)
	63.546±0.003 63.546±0.003 (abridged)
Copper in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson – ↑ Cu ↓ Ag nickel ← copper → zinc
Atomic number (Z)	29
Group	group 11
Period	period 4
Block	d-block
Electron configuration	[Ar] 3d10 4s1
Electrons per shell	2, 8, 18, 1
Physical properties
Phase at STP	solid
Melting point	1357.77 K ​(1084.62 °C, ​1984.32 °F)
Boiling point	2835 K ​(2562 °C, ​4643 °F)
Density (near r.t.)	8.96 g/cm3
when liquid (at m.p.)	8.02 g/cm3
Heat of fusion	13.26 kJ/mol
Heat of vaporization	300.4 kJ/mol
Molar heat capacity	24.440 J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 1509 1661 1850 2089 2404 2834
Atomic properties
Oxidation states	−2, 0, +1, +2, +3, +4 (a mildly basic oxide)
Electronegativity	Pauling scale: 1.90
Ionization energies	1st: 745.5 kJ/mol 2nd: 1957.9 kJ/mol 3rd: 3555 kJ/mol (more)
Atomic radius	empirical: 128 pm
Covalent radius	132±4 pm
Van der Waals radius	140 pm
Spectral lines of copper
Other properties
Natural occurrence	primordial
Crystal structure	​face-centered cubic (fcc)
Speed of sound thin rod	(annealed) 3810 m/s (at r.t.)
Thermal expansion	16.5 µm/(m⋅K) (at 25 °C)
Thermal conductivity	401 W/(m⋅K)
Electrical resistivity	16.78 nΩ⋅m (at 20 °C)
Magnetic ordering	diamagnetic
Molar magnetic susceptibility	−5.46×10−6 cm3/mol
Young's modulus	110–128 GPa
Shear modulus	48 GPa
Bulk modulus	140 GPa
Poisson ratio	0.34
Mohs hardness	3.0
Vickers hardness	343–369 MPa
Brinell hardness	235–878 MPa
CAS Number	7440-50-8
History
Naming	after Cyprus, principal mining place in Roman era (Cyprium)
Discovery	Middle East (9000 BC)
Symbol	"Cu": from Latin cuprum
Isotopes of copper v e
Main isotopes Decay abun­dance half-life (t1/2) mode pro­duct 63Cu 69.2% stable 64Cu synth 12.70 h β+ 64Ni β− 64Zn 65Cu 30.9% stable 67Cu synth 61.83 h β− 67Zn
Category: Copper view talk edit | references

Copper is one of the few metals that can occur in nature in a directly usable metallic form (native metals). This led to very early human use in several regions, from c. 8000 BC. Thousands of years later, it was the first metal to be smelted from sulfide ores, c. 5000 BC; the first metal to be cast into a shape in a mold, c. 4000 BC; and the first metal to be purposely alloyed with another metal, tin, to create bronze, c. 3500 BC.

In the Roman era, copper was mined principally on Cyprus, the origin of the name of the metal, from aes cyprium (metal of Cyprus), later corrupted to cuprum (Latin). Coper (Old English) and copper were derived from this, the later spelling first used around 1530.

Commonly encountered compounds are copper(II) salts, which often impart blue or green colors to such minerals as azurite, malachite, and turquoise, and have been used widely and historically as pigments.

Copper used in buildings, usually for roofing, oxidizes to form a green patina of compounds called verdigris. Copper is sometimes used in decorative art, both in its elemental metal form and in compounds as pigments. Copper compounds are used as bacteriostatic agents, fungicides, and wood preservatives.

Copper is essential to all living organisms as a trace dietary mineral because it is a key constituent of the respiratory enzyme complex cytochrome c oxidase. In molluscs and crustaceans, copper is a constituent of the blood pigment hemocyanin, replaced by the iron-complexed hemoglobin in fish and other vertebrates. In humans, copper is found mainly in the liver, muscle, and bone. The adult body contains between 1.4 and 2.1 mg of copper per kilogram of body weight.