What type of bond involves the sharing of electron pairs between atoms?

A covalent bond involves the sharing of electron pairs between atoms, allowing them to achieve a more stable electronic configuration. This type of bond commonly occurs between nonmetals, where atoms need to gain, lose, or share electrons in order to fill their outer electron shells and achieve a stable octet. For instance, in a water molecule (H2O), each hydrogen atom shares one of its electrons with the oxygen atom, resulting in two covalent bonds that hold the molecule together.

In contrast, ionic bonds arise from the transfer of electrons from one atom to another, resulting in the attraction between positively and negatively charged ions. Hydrogen bonds are not true bonds but rather intermolecular attractions that occur due to the partial charges in polar molecules. Metallic bonds involve a "sea of electrons" that are free to move among a lattice of metal cations, allowing for conductivity and malleability rather than the localized sharing of electron pairs characteristic of covalent bonds. Thus, the defining feature of covalent bonding is the sharing of electron pairs, making it the correct answer for this question.