Molecular Orbital Prediction of Chemical Reactivity

Mayer's suggestions (Mayer 1983, 1984) in ab initio SCF (Self' Consistent Field) theory have been  incorporated to the semi-empirical MINDO/3 method to evaluate valence indices of atoms in some trisubstituted benzenes. Chemical reactivity of different of atoms in  terms of Jug's (Jug 1984 a,b) normal, hyper and subvalences are discussed in terms of their affinities for covalent bond formation. The traditional view that valency is directly related to the atomic charge is found to be invalid. The valency of an atom in a molecule is a function of the orbital occupancies corrected for intraatomic terms, as the affinity of atoms for covalent bond formation changes from molecule to molecule. It should be mentioned that we are dealing with reactivity as a tendency for covalent bond formation; nucleophilic or electrophilic reactivity is thus excluded.