Periodic table / Transition metals

29Copper

Copper is a transition metal in group 11, period 4. At 25 °C it is a solid.

Cu
Shells: 2, 8, 18, 1. A simple picture: electrons do not move in circles.
Symbol
Cu
Atomic number
29 protons in the nucleus
Standard atomic weight
63.546 ± 0.003The isotope mix varies in normal samples, so the value cannot be given more precisely.
Electron configuration
[Ar] 3d10 4s1
Electrons in each shell
2, 8, 18, 1
Group, period, block
11, 4, d
Family
Transition metals
State at 25 °C
solid
Electronegativity
1.9 (Pauling scale)
First ionisation energy
745.5 kJ/mol (7.72638 eV)
Where these numbers come from

Atomic weight: IUPAC CIAAW, abridged standard atomic weights 2024. Electron configuration and ionisation energy: NIST Atomic Spectra Database. Family, state and electronegativity: PubChem. See Sources. Melting points, boiling points and densities are left out for now: published values differ between sources, and we will add them once each has been checked.