Copper (Cu)
Transition metal
Copper was the first metal humans worked, and it still wires the modern world: its superb electrical conductivity is second only to silver. Fresh copper is salmon-pink, weathering to brown and finally the famous green patina.
Position on the periodic table
Atomic properties
| Atomic number | 29 |
|---|---|
| Atomic mass | 63.5463 amu |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s1 3d10 |
| Noble gas shorthand | [Ar] 3d10 4s1 |
| Electrons per shell | 2, 8, 18, 1 |
| Valence electrons (outer shell) | 1 |
| Common oxidation states | +2, +1 |
| Electronegativity (Pauling) | 1.9 |
| Covalent radius (approx.) | 132 pm |
| First ionization energy | 745.5 kJ/mol |
| Electron affinity | 119.2 kJ/mol |
Physical properties
| State at 25 °C | Solid |
|---|---|
| Density | 8.96 g/cm³ |
| Melting point | 1084.6 °C (1357.8 K) |
| Boiling point | 2561.8 °C (2835 K) |
| Appearance | red-orange metallic luster |
| Radioactive | No |
| Origin | Occurs naturally |
Electron configuration of copper
Copper's ground-state electron configuration is 1s2 2s2 2p6 3s2 3p6 4s1 3d10, usually shortened to [Ar] 3d10 4s1. Its electrons occupy 4 shells (2, 8, 18, 1), placing it in period 4 of the d-block. Explore it interactively in the electron configuration calculator.
Uses of copper
- Electrical wiring and motors
- Plumbing pipes and roofing
- Alloys: brass (with zinc) and bronze (with tin)
- Antimicrobial touch surfaces
Biological role: Essential trace element — copper enzymes help form red blood cells and connective tissue.
Occurrence: Occasionally found as native metal; mainly mined from sulfide ores.
Common compounds of copper
History and discovery
Discovered: Known since ancient times — Middle East. Name origin: From Latin cuprum, after Cyprus, the Roman world's great copper source.
Worked since about 9000 BCE; the Bronze Age began when smiths learned to alloy copper with tin.
Safety notes
Copper surfaces and pipes are safe; soluble copper salts are toxic if swallowed in quantity.
Educational context only — always follow your school's laboratory rules and never handle chemicals without proper supervision. See our disclaimer.
Practice questions
Quick practice: Copper
1. What is the chemical symbol of Copper?
2. What is the atomic number of Copper?
3. Which category does Copper belong to?
4. What is the state of Copper at room temperature?
5. Which period of the periodic table is Copper in?
Copper FAQs
What is the atomic number of copper?
Copper's atomic number is 29 — every copper atom has 29 protons in its nucleus.
What is the symbol for copper?
Cu. From Latin cuprum, after Cyprus, the Roman world's great copper source.
Is copper a metal, nonmetal, or metalloid?
Copper is classified as a transition metal.
What state is copper at room temperature?
At about 25 °C, copper is a solid. It melts at 1084.6 °C.
What is copper used for?
Key uses include: electrical wiring and motors; plumbing pipes and roofing; alloys: brass (with zinc) and bronze (with tin).
Related elements
Keep working with this element
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