Question

Why do halogens possess very high values of electronegativity?

Answer 1

1. Halogen atoms have small atomic radii, meaning their outer electrons are close to the nucleus.
2. They have a high effective nuclear charge, which strongly attracts electrons towards the nucleus.
3. These two factors increase their ability to attract shared electrons in a bond.
4. Because of this, each halogen is the most electronegative element in its period.
5. Electronegativity decreases down the group as atomic size increases and effective nuclear charge decreases.
6. Fluorine has the highest electronegativity due to the smallest size and highest nuclear charge.

Hence, the small size and strong nuclear pull cause halogens to have very high electronegativity values.