Derivation and significance of valence molecular connectivity.

The physical basis for valence molecular connectivity was studied. The delta v and delta values are cardinal numbers describing the electronic structure of atoms in their valence states. The value delta v + delta describes the volume of a bonding atom while the value delta v - delta describes the electronegativity. By using the principle of electronegativity equalization, bond electronegativity is defined as (delta vi delta vj)-1/2, and the valence molecular connectivity index (l chi v) is derived as a sum of these bond descriptions. The valence chi index is interpreted in terms of the information encoded, describing both the volume and electronic characteristics of bonds in molecules. Examples of close relationships with molecular volume and electronic properties are shown. A new way of estimating valence state electronegativity is proposed from a count of exterjacent electrons divided by the quantum number squared for at least the first three quantum levels.