|red-orange metallic luster Native copper (~4 cm in size) |Name,
symbol, number||copper, Cu, 29| |Element category||transition
metal| |Group, period, block||11, 4, d| |Standard atomic
weight||63.546(3)| |Electron configuration||[Ar] 3d 4s 2, 8, 18,
1 |Naming||after Cyprus, principal mining place in Roman era
(Cyprium)| |Discovery||Middle Easterns (9000 BC)| |Density (near
r.t.)||8.96 g·cm| |Liquid density at m.p.||8.02 g·cm| |Melting
point||1357.77 K, 1084.62 °C, 1984.32 °F| |Boiling point||2835
K, 2562 °C, 4643 °F| |Heat of fusion||13.26 kJ·mol| |Heat of
vaporization||300.4 kJ·mol| |Molar heat capacity||24.440
J·mol·K| |Oxidation states||+1, +2, +3, +4 (mildly basic oxide)
|Electronegativity||1.90 (Pauling scale)| |1st: 745.5 kJ·mol|
|2nd: 1957.9 kJ·mol| |3rd: 3555 kJ·mol| |Atomic radius||128 pm|
|Covalent radius||132±4 pm| |Van der Waals radius||140 pm|
|Crystal structure||face-centered cubic| |Electrical
resistivity||(20 °C) 16.78 nΩ·m| |Thermal conductivity||401
W·m·K| |Thermal expansion||(25 °C) 16.5 µm·