Electronegativity, bond polarity, and why water is polar

Electronegativity is how strongly an atom attracts the shared electrons in a bond. It generally increases across a period from left to right and up a group, so fluorine is the most electronegative element. The difference in electronegativity between two bonded atoms predicts the kind of bond: a very small difference gives a nonpolar covalent bond with evenly shared electrons, a moderate difference gives a polar covalent bond with unevenly shared electrons, and a large difference, typical of a metal bonded to a nonmetal, gives an ionic bond. In water, oxygen pulls the shared electrons more strongly than hydrogen, and the molecule's bent shape keeps those pulls from canceling, so water is polar, with a slightly negative oxygen side and slightly positive hydrogen side. That polarity makes water very good at dissolving ionic and polar substances.

This explanation is AI-generated and can occasionally be wrong. 🚩 Report