Copper (Cu): Electron Configuration, Properties and Uses
Copper (Cu): Electron Configuration, Properties and Uses
Electron configuration [Ar] 4s1 3d10 · group 11 · period 4 · Ar 63.546
Copper data
- Atomic number
- 29
- Relative atomic mass
- 63.546
- Group
- 11
- Period
- 4
- Block
- d
- Category
- Transition metal
- Electron configuration
- [Ar] 4s1 3d10
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s1 3d10
- Electrons per shell
- 2, 8, 18, 1 (K L M N)
- Valence electrons
- 11
- Electronegativity (Pauling)
- 1.9
- First ionisation energy
- 7.726 eV
- Atomic radius (van der Waals)
- 140 pm
- State at room temperature
- Solid
- Melting point
- 1085 °C
- Boiling point
- 2562 °C
- Density
- 8.933 g/cm³
- Common oxidation states
- +2, +1
- Discovered
- ancient times
Source: PubChem (NIH, accessed 13 Nov 2026); atomic mass: IUPAC standard atomic weight.
Electron shell diagram
K 2 · L 8 · M 18 · N 1
Orbital diagram (outer electrons)
About copper
Copper, symbol Cu, is element number 29 in the periodic table. It is a transition metal in group 11, period 4, d-block. Copper has been known and used since ancient times. The symbol Cu comes from the Latin cuprum, after Cyprus, the Roman source of copper. Copper is a solid at room temperature, melting at 1085 °C and boiling at 2562 °C.
Copper electron configuration
The electron configuration of copper is 1s2 2s2 2p6 3s2 3p6 4s1 3d10, or in short [Ar] 4s1 3d10. Its electrons occupy 4 shells: K = 2, L = 8, M = 18, N = 1. For transition metals, valence electrons are counted from the 4s and 3d subshells: 1 + 10 = 11, matching group 11. This is an exception to the Aufbau rule: the usual filling order predicts [Ar] 4s2 3d9, but a full 3d subshell is more stable, so an electron moves from the s subshell into 3d. When it forms cations, electrons leave the outermost subshell first: Cu+ = [Ar] 3d10; Cu2+ = [Ar] 3d9.
Filling order: 1s2(2) → 2s2(4) → 2p6(10) → 3s2(12) → 3p6(18) → 4s1(19) → 3d10(29)
Uses of copper
Well-known applications of copper include electrical wiring, plumbing, brass and bronze, and copper sulfate fungicides. For research and analysis you can browse copper compounds in the AMI Scientific catalogue.
Safety
Copper metal is safe, but soluble copper salts such as CuSO4 are harmful if swallowed and very toxic to aquatic life. Always read the safety data sheet (SDS) before working with a chemical.
Other elements in group 11
Frequently asked questions
What is the electron configuration of copper?
The electron configuration of copper (Cu, atomic number 29) is 1s2 2s2 2p6 3s2 3p6 4s1 3d10, or [Ar] 4s1 3d10 in short. By shell: 2, 8, 18, 1.
How many valence electrons does copper have?
Copper has 11 valence electrons.
Which group and period is copper in?
Copper is in group 11, period 4, d-block.
What is the atomic mass of copper?
The relative atomic mass of copper is 63.546. Use it to calculate molar mass with the molar mass calculator.
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