What type of bond involves sharing a pair of electrons between atoms?

A covalent bond is characterized by the sharing of a pair of electrons between two atoms. This type of bond typically occurs between nonmetal atoms that have similar electronegativities, allowing them to share electrons rather than transferring them. By sharing electrons, the atoms can achieve a more stable electron configuration, resembling that of noble gases. This sharing creates a strong connection between the atoms, resulting in the formation of molecules.

In contrast, an ionic bond involves the transfer of electrons from one atom to another, resulting in the formation of positively and negatively charged ions that attract each other. Metallic bonds are characterized by a 'sea of electrons' that are delocalized over a lattice of metal cations, allowing for conductivity and malleability. Hydrogen bonds are relatively weak attractions between a hydrogen atom covalently bonded to a highly electronegative atom and another electronegative atom, which is not the basis of electron sharing between atoms.

Understanding the nature of these various types of bonds clarifies the distinct way electrons behave and interact in different chemical environments, with covalent bonds specifically involving the sharing mechanism that defines their formation.