The electronegativity scale of Allred and Rochow: revisited

摘要

A new scale of electronegativity (χ), based on the view that χ is an atomic property and electronegativity is the force exerted by the screened nucleus on an electron at the periphery of an atom, has been designed and framed. The necessary ansatz used was suggested by Allred and Rochow, χ = Force = e 2 (Z eff)/r 2 where e is the electronic charge (esu), Z eff is the effective nuclear charge and r is the absolute (most probable) radius. The electronegativity is calculated in appropriate force unit. We have posited that the absolute (most probable) and not the covalent radii should be the appropriate size descriptor in evaluating electronegativity of atoms. It has been also demonstrated that all previous calculations of electronegativities using Allred and Rochow ansatz suffer from dimension mismatch. We have computed the electronegativities of 103 elements of the periodic table in force (dynes/electron) unit by invoking the electronegativity ansatz of Allred and Rochow, using the absolute radii and effective nuclear charge of Ghosh et al. The new scale of electronegativity satisfies all the sine qua non of a scale of electronegativity.