Copper (Cu)
Copper is element 29, a transition metal in period 4, group 11 of the periodic table. At room temperature it is a solid.
Electron configuration [Ar] 3d10 4s1
Electrons per shell 2, 8, 18, 1
Copper data
| Atomic number | 29 |
|---|---|
| Symbol | Cu |
| Atomic mass | 63.546 u |
| Category | Transition metal |
| Group | 11 |
| Period | 4 |
| Block | d |
| State at 25 °C | solid |
| Melting point | 1358 K (1084.9 °C) |
| Boiling point | 3200 K (2926.9 °C) |
| Density | 8.92 g/cm³ |
| Electronegativity (Pauling) | 1.9 |
| Atomic radius | 138 pm |
| 1st ionization energy | 746 kJ/mol |
| Electron affinity | -118 kJ/mol |
| Oxidation states | +1, +2, +3, +4 |
| Common ion charge | +, 2+ |
| Discovered | Known since antiquity |
Orbital diagram
Each box is one orbital holding up to two electrons of opposite spin. Following Hund’s rule, electrons spread out singly across a subshell before pairing.
Work through copper’s configuration and its ions →
Where copper sits
Copper belongs to the transition metals. Its Pauling electronegativity of 1.9 is mid-range; see the electronegativity chart and periodic trends for context. To use its mass in a calculation, try the molar mass calculator.
Copper FAQ
What is the electron configuration of copper?
Copper (Z = 29) has the configuration 1s2 2s2 2p6 3s2 3p6 3d10 4s1. In noble-gas shorthand that is [Ar] 3d10 4s1. This is an exception to the simple Aufbau prediction (1s2 2s2 2p6 3s2 3p6 3d9 4s2); a half-filled or filled subshell lowers the energy.
How many valence electrons does copper have?
11 (1 outer s + 10 d electrons; 1 in the outermost shell).
What is the atomic mass of copper?
The standard atomic weight of copper is 63.546 u, so one mole weighs 63.546 g.
Is copper a metal?
Yes. Copper is a transition metal.
What is the charge of a copper ion?
Copper most commonly forms Cu+ or Cu2+.