How does electronegativity change down a group on the periodic table?

Electronegativity, which is defined as the tendency of an atom to attract shared electrons in a chemical bond, generally decreases as you move down a group on the periodic table.12

This trend occurs because, as you move down a group, the atomic size of the elements increases. As the atoms become larger, the valence electrons are located at an increasing distance from the positive nucleus, which reduces the atom's ability to attract additional electrons. Consequently, elements at the top of a group are typically more electronegative than those at the bottom.21