Question

What are the oxidation states of copper?

Answer 1

Hint: An oxidation number or oxidation state of any atom represents its capability to gain or lose electrons. Oxidation state of any element can be identified by its electronic configuration, and the configuration of its fully filled stable state. Copper is an element of the transition elements of the d block so it has variable oxidation states.

Complete answer:
Oxidation state of any element is its ability to gain electrons or lose electrons. Copper is a d – block, transition metal that has an atomic number 29. d – Block elements have a property that the valence electron in their atoms, enters into the d – orbital. The d – orbital is either partially filled or fully filled, in their ground state or their most stable states.
The electronic configuration of copper is$[Ar]4{{s}^{1}}3{{d}^{10}}$, copper exist in two oxidation states, +1 and +2, both being positive as copper can donate electrons. When copper has an oxidation state of +1 it is called cuprous, this is as the 4s electron gets removed. But copper has a more stable +2 oxidation state called cupric. This is because the d – orbital will be half filled in +2 oxidation state that results in high negative enthalpy of hydration that makes it more stable in forming aqueous solutions.
So, oxidation states of copper are +1 and +2.

Note:
The hydration enthalpy is the ability to be added to the water molecules. The +2 oxidation state of copper enables it to form stronger bonds and release more energy due to partially filled d – orbital. The variable oxidation states of d – block elements make their properties similar to each other. The valency of these elements are written as Roman numerals along with their name in a compound.