# How would you calculate oxidation number?

Oct 31, 2015

I will take a simple example, $C l - F$. Fluorine is the most electronegative element; if the $C l - F$ bond is broken we get the ions $C {l}^{+}$, and ${F}^{-}$. So by the above definition oxidation numbers are (we use Roman numerals) ${I}^{+}$, and $I -$, for chlorine and fluorine respectively. The charges must sum up to the charge on the original species which was $0$.