Which type of chemical bond is characterized by shared electrons?

The type of chemical bond characterized by shared electrons is a covalent bond. In a covalent bond, two atoms share one or more pairs of electrons, which allows each atom to achieve a more stable electron configuration, often resembling that of noble gases. This sharing can occur equally, leading to nonpolar covalent bonds, or unequally, resulting in polar covalent bonds.

Covalent bonds are fundamental in forming molecules, as they directly affect a compound's properties, such as boiling and melting points, as well as its solubility.

In contrast, ionic bonds involve the transfer of electrons from one atom to another, resulting in the formation of charged ions. Metallic bonds involve the pooling of electrons among a lattice of metal atoms, which is distinct from the sharing seen in covalent bonds. Hydrogen bonds are relatively weak attractions between a hydrogen atom and an electronegative atom, which also do not involve electron sharing in the typical sense of a covalent bond. Thus, the defining feature of shared electrons clearly identifies covalent bonds as the correct answer.