Copper is a fascinating element in the periodic table because it can exist in two oxidation states: +1 and +2. This ability is primarily due to its electronic configuration and the stability of its oxidation states.
Copper has the electron configuration of [Ar] 3d10 4s1. When it loses one electron to form the +1 oxidation state, it can lose the single 4s electron, resulting in the configuration [Ar] 3d10. This +1 ion, known as cuprous ion (Cu+), is stable because the 3d subshell is completely filled, making it energetically favorable.
In the +2 oxidation state, copper loses two electrons, including the one from the 4s subshell and one from the 3d subshell, leading to the configuration [Ar] 3d9. This ion is called cupric ion (Cu2+). Although the 3d subshell is no longer fully filled, the +2 state is stable due to the effective nuclear charge experienced by the remaining electrons and the overall energy considerations involved in oxidation and reduction reactions.
In summary, copper can exhibit both +1 and +2 oxidation states due to the unique arrangement of its electrons and the stability associated with each ion. This dual ability makes copper versatile in various chemical reactions and compounds.