Difference Between Oxidation Number and Valency-
1. Oxidation state is the amount of charge on an atom which is developed in the formation of a molecule, while valency is the capacity of an atom to combine with the same or different atoms to give compounds.
2. Oxidation state may be positive, negative or fractional, while valency is a number (positive and negative signs are not associated with valency).
3. Oxidation state for an element may be different in different compounds, e.g. oxidation state of C in CH4, CH3CI, CH2Cl2, CHCl3 and CCl4 are -4, -2, 0, +2 and +4 respectively, while valency for carbon is 4 in all the above compounds.
