Electronegativity help

Question

I was told to tell based on using if a molecule is polar non polar or having hydrogen bonds to determine electronegativity along with the total number of electrons

 

However when I got to NH2NH2 and H2O2 they have the same number of electrons and are both hydrogen bounding polar.

So how do you determine which is more electronegative? I assume there is an easy mathematic or whatever way to do this I just don't know how.

 

Answer 1

If you look in a chem book, you should be able to find a periodic table that has the electronegativity values associated with each element. In your case you are looking at N, H, and O.

 

The electronegativity value for N is 3.0, O is 3.5 and H is 2.1. The larger the difference, the more electronegative something is. In your case, the bonds in your hydrogen peroxide (H₂O₂) are going to be more electronegative.