How does electronegativity change across the periodic table?

Electronegativity, which is the ability of an atom to attract shared electrons in a chemical bond, follows a clear trend across the periodic table.12

• Across a period: Electronegativity generally increases as you move from left to right.
• Down a group: Electronegativity generally decreases as you move from top to bottom.

Consequently, the elements with the highest electronegativities are located in the upper right-hand corner of the periodic table, near fluorine, which is the most electronegative element. Conversely, elements with the lowest electronegativities—often described as electropositive—are found in the lower left-hand corner, such as cesium or francium.231

This trend is closely related to ionization energy and electron affinity. Atoms with high electronegativities have high ionization energies and high electron affinities, making them more likely to attract electrons and form anions. Elements with low electronegativities have low ionization energies and low electron affinities, making them more likely to lose electrons and form cations.2