# How do you use electronegativity values to determine the one element that always has a negative oxidation number when it appears in any binary compound?

Mar 11, 2017

#### Answer:

Well, which is the most electronegative element.........?

#### Explanation:

On most electronegativity scales, fluorine is the most electronegative element. What does electronegativity mean? It is conceived to be the ability of an atom involved in a chemical bond to polarize electron density towards itself.

So let's look at some simple compounds (or molecules) of fluorine: interhalogens, $F - X$; and $O {F}_{2}$. The oxidation states of the heteroatom are ${X}^{+ I}$ and ${O}^{+ I I}$, and of course we have ${F}^{- I}$. What is the oxidation number of fluorine in molecular fluorine, ${F}_{2}$?

As a curiosity that speaks to fluorine's oxidizing ability, and reactivity, some fluorine chemists I have met are missing eyes or fingers after a laboratory accident. Fluorine chemistry is to be approached with care.