Why does electronegativity decreases as you go down a group on the periodic table?

Electronegativity decreases as you go down a group in the Periodic Table primarily due to the increasing atomic radius and the addition of electron shells. As more energy levels are added, the valence electrons are farther from the nucleus, resulting in a weaker attractive force between the nucleus and the valence electrons. Additionally, the shielding effect from inner electron shells reduces the nucleus's ability to attract bonding electrons. Consequently, elements lower in a group have lower electronegativity values.