Definitions Valence, Oxidation State, Formal Charge, and Coordination Number

24 DEFINITIONS VALENCE, OXIDATION STATE, FORMAL CHARGE, AND COORDINATION NUMBER 

Valence is most simply defined as the number of electrons an atom uses in bonding. More accurately, valence may be defined as the number of valence electrons in an atom minus the number of nonbonding electrons on the atom in the molecule in question.. Using either of these definitions, we may readily see that the valence of sulfur is 2, 4, and 6 in H2S, SF4, and SFs, respectively  

Valence is often confused with OS (also called oxidation number, ON) and less frequently with CN. Not infrequently, valence equals OS. For example, the valence and OS of carbon in CF4 are each 4 the same holds for CO2. Consider, however, CH2F2 and H2CO carbon 

TABLE 1.7 Definitions of Vaience, Oxidation State, Formai Charge, and Coordination Number 

This table Is adapted trom Parkin, G. J. Chem. Educ. 2006, 83, 791-799. 

---