![Copper element card: symbol Cu, atomic number 29, atomic mass 63.546, electron configuration [Ar] 3d¹⁰ 4s¹, oxidation states +2, Transition metal, group 11, period 4, solid at room temperature.](https://stage.chemistry-dictionary.com/wp-content/uploads/2026/09/copper-chemical-element.webp)
Copper sits in group 11 of the periodic table. It is one of the few metals found in nature in a pure, usable form. Freshly exposed, pure copper has a distinct pinkish-orange color.
Over time, the metal reacts with oxygen, water, and carbon dioxide (CO2) in the air. This slow chemical reaction creates a protective green surface layer. We call this green layer a patina, and it consists of copper carbonate.
A common student misconception is that this green color means the metal has ruined or rusted like iron. In truth, this layer actually shields the inner metal from further damage. Copper forms many different chemical compounds and coordination salts.
It usually takes a +1 or +2 oxidation state when dissolved in water solutions. The metal is widely distributed throughout the Earth’s crust. It is most often found as sulfide minerals like chalcopyrite and chalcocite.
Workers heavily mine, crush, and melt these mineral ores for modern commercial applications. Copper features a unique electron structure. It possesses a completely full d-subshell and a single s-electron.
This specific electron arrangement lets its valence electrons move freely, making copper an outstanding conductor of heat and electricity. Among all pure metals, only silver conducts electricity better than copper.