In polar covalent bonds, how is the electron distribution described?

Polar covalent bonds arise when two atoms with different electronegativities form a bond. Electronegativity is the tendency of an atom to attract electrons in a bond. When one atom is more electronegative than the other, it attracts the shared electrons more strongly, resulting in an unequal distribution of electron density. This difference in electron sharing leads to the formation of a dipole moment, where one end of the bond becomes slightly negative and the other slightly positive.

This unequal sharing is a hallmark of polar covalent bonds and underscores the key characteristic that differentiates them from nonpolar covalent bonds, where electrons are shared equally, and ionic bonds, where electrons are completely transferred from one atom to another. The correct answer succinctly captures the essence of how electron distribution occurs in polar covalent bonds, emphasizing the role of differing electronegativities in shaping the nature of the bond.