Copper
Element 29 · Transition Metal
Copper is a distinctive reddish-orange transition metal and one of the pillars of civilization — the Bronze Age began when it was alloyed with tin. Like chromium it has an anomalous electron configuration ([Ar] 3d10 4s1), since a full 3d subshell is especially stable. It conducts heat and electricity second only to silver among pure metals.
Exposed to air, copper slowly develops a green patina of basic copper carbonate, the color of old rooftops and statues. It is also an essential trace element: enzymes throughout the body depend on copper, though large doses are toxic.
Key facts
| Atomic number | 29 |
|---|---|
| Atomic weight | 63.546 |
| Category | Transition Metal |
| Group / Period | 11 / 4 |
| Block | d |
| Electron configuration | [Ar] 3d10 4s1 |
| Common oxidation states | +2, +1 |
| State at STP | Solid |
| Electronegativity | 1.90 |
| Atomic radius | 145 pm |
| Density | 8.96 g/cm³ |
| Melting point | 1084.62 °C |
| Boiling point | 2562 °C |
Occurrence
Copper occurs as native metal in some deposits and more commonly in sulfide ores such as chalcopyrite and in colorful carbonate minerals like malachite and azurite. Humans have mined it for about 10,000 years, making it one of the first metals ever used.
Applications
Electrical wiring and electronics depend on copper's superb conductivity
Plumbing and roofing use copper for corrosion resistance and workability
Bronze and brass alloys serve in bearings, instruments, and fittings
Coins in many currencies are copper-plated or copper alloys
Copper surfaces and fungicides exploit its antimicrobial properties
Common compounds
- copper(II) sulfate
- copper(II) oxide
- copper(I) chloride
- copper carbonate
The Statue of Liberty's green color is a copper patina about as thick as two pennies.
Data source: IUPAC standard atomic weights 2021