ABSTRACT
The covalent bonds holding the atoms together in any molecule are pairs of electrons confined to molecular orbitals. Molecules, including proteins, are arrays of atomic nuclei required to maintain particular distances and angular dispositions relative to each other by electrons confined to particular regions of space known as orbitals. Valence electrons are the outermost electrons surrounding each atom. All of the chemistry of a molecule, which is the consequence of its chemical bonds and its sites of reactivity, results from these valence electrons. The quantitative measure of the basicity of a lone pair of electrons is the microscopic acid dissociation constant of its conjugate acid. Electronegative or electropositive atoms adjacent to the central atom also have a significant but less remarkable effect on acidity. A pair of bonding electrons occupies a bonding molecular orbital that is formed from the overlap of two or more atomic orbitals, each contributed by a different atom in the molecule.
