Electronegativity (χᵣ) is a measure of the ability of an atom in a molecule to attract the shared bonding electrons towards itself. The greater an atom's electronegativity, the more strongly it pulls electron density in a bond. Differences in electronegativity between bonded atoms determine bond polarity; fluorine is the most electronegative element.

电负性(χᵣ)是分子中某原子把共享成键电子吸引向自己的能力的量度。原子的电负性越大,在键中吸引电子密度的能力越强。成键原子之间的电负性差异决定键的极性;氟是电负性最大的元素。