Copper is the 29th element in the periodic table, and its symbol is Cu. It is a reddish, extremely ductile metal of Group 11 (Ib) of the periodic table, an excellent conductor of electricity and heat. Copper is found in the free metallic state in nature. This native Copper was first used (c. 8000 BCE) as a substitute for stone by Neolithic (New Stone Age) humans. Metallurgy dawned in Mesopotamia as Copper was cast to shape in molds (c. 4000 BCE), was reduced to metal from ores with fire and charcoal, and was intentionally alloyed with tin as bronze (c. 3500 BCE). The Roman supply of Copper came almost entirely from Cyprus. It was known as aes Cyprium, “metal of Cyprus,” shortened to cyprium and later corrupted to cuprum.

The total number of electrons in Copper is twenty-nine. These electrons are arranged according to specific rules in different orbitals. The arrangement of electrons in Copper in specific rules in different orbits and orbitals is called the electron configuration of Copper. The electron configuration of Copper is [Ar] 3d10 4s1 if the electron arrangement is through orbitals. Electron configuration can be done in two ways.

Electron configuration through orbit (Bohr principle)

Electron configuration through orbital (Aufbau principle)

Electron configuration through orbitals follows different principles. For example, the Aufbau principle, Hund’s principle, and Pauli’s exclusion principle. The expected electron configuration for Copper will be 1s²2s²2p⁶3s²3p⁶3d⁹4s²(when writing the electron configuration for an atom like Cu, the 3d is usually written before the 4s.)

However, half-filled and fully-filled subshells have extra stability. Therefore, one of the 4s2 electrons jumps to the 3d9. This gives us the (correct) configuration of 1s²2s²2p⁶3s²3p⁶3d¹⁰4s¹.

For the Cu+ ion, we remove one electron from 4s1, leaving us withm 1s²2s²2p⁶3s²3p⁶3d¹⁰.

For the Cu2+ ion, we remove a total of two electrons (one from the 4s1 and one from the 3d10), leaving us with: 1s²2s²2p⁶3s²3p⁶3d⁹.