Copper 铜

[Ar] 3d¹⁰ 4s¹

Electron configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s¹

3d ↑↓↑↓↑↓↑↓↑↓

4s ↑

Mass number A	Atomic mass / u	Abundance
⁶³Cu	62.929597	69.15 %
⁶⁵Cu	64.927790	30.85 %

Isotope masses: AME2020; abundances: IUPAC/CIAAW representative values.

Copper flame · blue-green

The lessons that discuss this element most (ranked by mentions).

$\ce{Cu+(aq)} + \ce{e-} \mathrel{\ce{->}} \ce{Cu(s)}$	+0.521 V
$\ce{Cu^2+(aq)} + \ce{2e-} \mathrel{\ce{->}} \ce{Cu(s)}$	+0.342 V
$\ce{Cu^2+(aq)} + \ce{e-} \mathrel{\ce{->}} \ce{Cu+(aq)}$	+0.153 V
$\ce{Cu(OH)2(s)} + \ce{2e-} \mathrel{\ce{->}} \ce{Cu(s)} + \ce{2OH-(aq)}$	−0.222 V
$\ce{Cu2O(s)} + \ce{H2O(l)} + \ce{2e-} \mathrel{\ce{->}} \ce{2Cu(s)} + \ce{2OH-(aq)}$	−0.360 V

Data: PubChem periodic table (public domain); atomic weights are IUPAC abridged standard values; covalent radii from Cordero et al. (2008).