WHAT IS COVALENCY,OXIDATION STATE

covalency means to form a bond by sharing of electrons by two atoms equally.

in this way they complete their electron octet[normally].

oxidation no is the residual charge which an atom appears to have when other atoms are withdrawn from the molecules as ioins by counting electrons with more electronegativity atoms.

increase of ox no is oxidation.

oxidation no and oxidation state is almost same.

Oxidation states are used to determine the degree of oxidation or reduction that an element has undergone when bonding. The oxidation state of a compound is the sum of the oxidation states of all atoms within the compound, which equals zero unless the compound is ionic