National League for Nursing (NLN PAX) Practice Exam

A covalent bond is formed when two atoms share a pair of electrons. This type of bond typically occurs between nonmetal atoms, which have similar electronegativities. By sharing electrons, these atoms can each achieve a more stable electron configuration, usually resembling that of the nearest noble gas. Covalent bonds can involve single, double, or even triple pairs of shared electrons, depending on the number of pairs shared between the two atoms.

This sharing of electrons allows for the formation of molecules, which are distinct entities with specific properties. For example, in a water molecule (H2O), each hydrogen atom shares an electron with the oxygen atom, resulting in a stable arrangement that is critical for many chemical processes in nature.

Ionic bonds, on the other hand, involve the transfer of electrons from one atom to another, leading to the formation of charged ions that attract each other. Hydrogen bonds are weaker interactions based on attractions between molecules due to partial charges, often involving hydrogen atoms. Metallic bonds involve a "sea of electrons" that are shared among a lattice of metal cations, which is quite different from the direct sharing in covalent bonds.