Copper
Atomic Data
| Atomic Number | 29 |
| Symbol | Cu |
| Atomic Weight | 63.546 u |
| Density (STP) | 8.96 g/cm³ |
| Melting Point | 1084.62 °C (1357.77 K) |
| Boiling Point | 2561.85 °C (2835 K) |
| Electronegativity | 1.9 (Pauling) |
| Electron Config. | 1s2 2s2 2p6 3s2 3p6 3d10 4s1 |
| Oxidation States | +1, +2 |
| Phase at STP | Solid |
| Category | Transition Metal |
| Period / Group | 4 / 11 |
| CAS Number | 7440-50-8 |
Electron Configuration
[Ar] 3d10 4s1
| Shell | n | Subshell | Electrons | Cumulative |
|---|---|---|---|---|
| K | 1 | 1s | 2 | 2 |
| L | 2 | 2s | 2 | 4 |
| L | 2 | 2p | 6 | 10 |
| M | 3 | 3s | 2 | 12 |
| M | 3 | 3p | 6 | 18 |
| M | 3 | 3d | 10 | 28 |
| N | 4 | 4s | 1 | 29 |
| Total | 29 | 29 | ||
Abundance & Occurrence
Copper is present in Earth's crust at approximately 60 ppm by mass and at approximately 6 ppm by mass throughout the universe.
Earth's Crust (ppm by mass)
Universe (ppm by mass)
Discovery & History
Read more about the discovery of the periodic table of elements →
Safety & Handling
- Copper fume fever: Inhaling freshly generated copper fume (from welding, brazing, or smelting) causes metal fume fever: a flu-like illness with fever, chills, and muscle aches; symptoms resolve within 24–48 hours but recur with each exposure.
- Copper dust inhalation: Fine copper dust irritates the respiratory tract and mucous membranes; chronic exposure to copper dusts has been associated with liver damage and, in rare cases, Wilson's disease-like copper accumulation.
- Skin and eye contact: Copper compounds (copper sulfate, copper chloride) cause skin and eye irritation; concentrated solutions are corrosive and cause chemical burns.
- Aquatic ecotoxicity: Copper is highly toxic to aquatic organisms at low concentrations; copper-containing effluents must not be discharged untreated: they cause significant ecotoxicological harm to freshwater invertebrates and fish.
Copper in the Real World
Real-World Uses
- Electrical wiring: Copper's combination of high electrical conductivity, ductility, and moderate cost makes it the dominant conductor material in building wiring, power cables, motors, and transformers globally.
- Plumbing: Copper pipe systems resist corrosion in both hot and cold water, carry no taste or odour, and are easily soldered, making them standard in residential and commercial plumbing for over a century.
- Alloys: Brass (Cu-Zn) and bronze (Cu-Sn) are used in plumbing fittings, musical instruments, bearings, ship propellers, and decorative hardware; beryllium copper is used in precision springs and electrical connectors.
- Antimicrobial surfaces: Copper and its alloys kill a wide range of bacteria, viruses, and fungi on contact; hospitals are increasingly fitting copper-alloy touch surfaces (door handles, bed rails, taps) to reduce healthcare-associated infections.
- Electronics and printed circuit boards: Electrodeposited and etched copper traces on PCBs carry signals between components; copper pillars and bond wires connect semiconductor dies to packages in integrated circuit manufacturing.
- Roofing and architecture: Sheet copper develops a green patina (verdigris) that protects the metal from further corrosion, used on domes, gutters, flashings, and cladding on landmark buildings such as the Statue of Liberty.
Downloadable Resources
Free periodic table reference sheets for classrooms, study sessions, and laboratory use.
Frequently Asked Questions
What is copper used for?
Copper is the world's third most widely used metal. Its exceptional electrical conductivity makes it the standard material for electrical wiring in buildings, vehicles, and electronics. Copper is also used in plumbing pipes, roofing, heat exchangers, and as the base for alloys including brass (with zinc) and bronze (with tin), which have been used by humans for thousands of years.
Is copper toxic?
Copper is an essential nutrient for all living things, required for enzyme function and the formation of red blood cells. However, excess copper is toxic: ingesting large amounts can cause nausea, liver damage, and Wilson's disease (a genetic disorder causing copper accumulation). Copper surfaces are naturally antimicrobial, killing bacteria and viruses on contact within minutes, a property exploited in hospital equipment.
How was copper discovered?
Copper is one of the oldest metals used by humans, with artefacts dating back over 10,000 years. It was the first metal to be widely smelted, marking the Chalcolithic (Copper Age) period. The name copper derives from 'Kyprios', the Latin and Greek name for Cyprus, which was the main source of copper in the ancient Mediterranean world.
Why is copper used for electrical wiring?
Copper has the second highest electrical conductivity of any element after silver, and is far cheaper than silver. It is also flexible, easy to draw into thin wire, resistant to corrosion, and straightforward to join by soldering. These combined properties: not any single one: make copper the practical standard for electrical wiring worldwide.