# What is the electronegativity difference in a homonuclear diatomic molecule?

Jul 14, 2017

Zero.

#### Explanation:

Electronegativity is a measure of how well an atom can pull electrons to itself.

If two atoms in a bond have different electronegativities, the electron density will be pulled towards the atom with the higher electronegativity, i.e. in $H - C l$, $C l$ is more electronegative creating, ${H}^{\delta +} - C {l}^{\delta -}$.

However, if it was the same on both atoms, they would have an equal pull on the electrons.

For example, $H - H$ has no dipole. If a bond is non-polar it will form a temporary dipole due to the instantaneous movement of the electrons around both nuclei, sometimes giving an uneven electron distribution.