How does the oxidation number relate to valency?

The oxidation number is a measure of the number of electrons that an atom uses to bond with another atom, similar to valency.

The oxidation number, also known as oxidation state, is a concept in chemistry that helps to keep track of electrons in an atom. It is a measure of the degree of oxidation or reduction of an atom in a chemical compound. The oxidation number of an atom is the charge that atom would have if the compound was composed of ions. It is a way of keeping track of electrons and is used in balancing chemical equations.

On the other hand, valency is a measure of the ability of an atom to bond with other atoms. It is determined by the number of electrons in the outermost shell of an atom that are available for bonding. In other words, valency is the combining power of an element.

The oxidation number and valency are related because they both involve the number of electrons an atom uses to form a bond. However, they are not always the same. For example, in many compounds, oxygen has an oxidation number of -2, but its valency is 2 because it can accept two electrons to achieve a stable electron configuration.

In simple terms, the oxidation number can be thought of as the charge an atom would have if all shared electrons were assigned to the atom with the greater electronegativity, while the valency is the number of bonds an atom can form. Both concepts are fundamental to understanding chemical reactions and bonding.