Question

differentiate between valency and oxidation number

Answer 1

The combining power or the combining capacity of an atom or an element is called its VALENCY. The number of other atoms of other elements with which one atom of an element combines is decided by the valency of that element.  In AlCl3 the valency of Al is 3 and it combines with three atoms of Al.

 Oxidation number is the residual charge which an atom has or appears to have when other elements are removed as ions by counting the number of shared electrons.

 For example, the oxidation number of N in NH3 is- 3.

 

Answer 2

Valency is the maximum number of electrons that an atom of any element loses or gain i.e It is the number of chemical bonds an atom can form.

Ex: Valency of oxygen is 2 because it needs only 2 electrons.

Oxidation Number: It is the actual number of electrons that an element lose or gain.

Ex: Most of the elements in oxygen have an oxidation state of -2.