Question

What is the difference between valency and Oxidation State in context 2 Chapter metals and nonmetals?

Answer 1

. Valency is the maximum no. of electrons which an atom can lose or gain while oxidation no. is the actual no. of electrons which the element lose or gain to form a molecule.
2. Valency is the property of an isolated atom while oxidation state is calculated for an atom is present in a molecule i.e, in a bonded state.
3. Valency of an element remains the same while its oxidation state may be different in different molecules.


An oxidation state is a number that is assigned to an element in a chemical combination. This number represents the number of electrons that an atom can gain, lose, or share when chemically bonding with an atom of another element.
The increase in oxidation state of an atom through a chemical reaction is known as an oxidation; a decrease in oxidation state is known as reduction. Such reactions involve the formal transfer of electrons, a net gain in electrons being a reduction and a net loss of electrons being an oxidation. For pure elements, the oxidation state is zero.
The valency of an element measures its ability to combine with other elements. The valency is determined by the number of electrons in the outer shell of each atom of an element.

Eg.

1) two atoms of aluminium combine with 3 atoms of oxygen. Thus oxidation state of aluminium is 3 ( so is its valency ).

2) one atom of chlorine combine with one atom of hydrogen. Thus oxidation state of chlorine is 1 ( so is its valency ).