What characterizes a covalent bond?

A covalent bond is characterized by the sharing of a pair of electrons between two atoms. This type of bond typically occurs between nonmetals, where the atoms involved have similar electronegativities, allowing them to share electrons more or less equally. When two atoms share one or more pairs of electrons, they form a stable balance that holds the atoms together.

In the case of the statement you selected, the mention of "unequally shared" can relate to polar covalent bonds, where there is an unequal sharing of electrons due to differences in electronegativity. However, the key characteristic of covalent bonding remains the sharing of electron pairs rather than transferring them completely, which distinguishes it from ionic bonds.

Understanding covalent bonds is crucial in chemistry as they form the backbone of many biological molecules, including DNA, proteins, and carbohydrates, playing a vital role in the structure and function of living organisms.