What is a polar covalent bond?

A polar covalent bond is characterized by the unequal sharing of electrons between two atoms. This situation arises when the two atoms involved have different electronegativities, which is the measure of an atom's ability to attract and hold onto electrons.

In a polar covalent bond, the atom with the higher electronegativity attracts the shared electron pair more strongly than the atom with the lower electronegativity. This creates a dipole moment, where one end of the bond becomes slightly negative, and the other end becomes slightly positive, resulting in molecular polarity.

This concept is crucial in understanding molecular interactions and reactivity, as polar molecules often exhibit different physical and chemical properties compared to nonpolar molecules. For example, polar molecules tend to dissolve well in polar solvents, leading to significant implications in various chemical processes.

The other definitions do not accurately capture the essence of a polar covalent bond. Equal sharing of electrons refers to nonpolar covalent bonds, complete electron transfer describes ionic bonds, and the notion that a polar covalent bond can only be formed between identical atoms incorrectly suggests that polarity is dependent on identical atomic structure, which is not the case.