A NEW SCALE OF ELECTRONEGATIVITY BASED ON ABSOLUTE RADII OF ATOMS
Abstract
A new scale of electronegativity is designed on the basis of the environment independent absolute radii of atoms. In this scale, the electronegativity is an intrinsic free-atom property and the basis of assumption is quantum mechanically viable. The qualitative relation between the size and electronegativity is relied upon and a quantitative general formula of evaluation of electronegativity in terms of the absolute radii of atoms is suggested as χ = a × (1/R)+ b, where χ is electronegativity and R is absolute radius of atoms, a and b are two constants determined by least square fitting for each period of elements separately. A number known as electronegativity is computed for each 103 elements of periodic table through the above formula and the unit assigned to χ is energy. The new scale of electronegativity is found to observe the simple rules that all the scales of electronegativity must obey. The evaluated scale reproduces the silicon rule where the electronegativities of the eight elements of metalloid group are very close to each other and the electronegativity of silicon atom is smallest of the group. A striking feature of the new scale is that the electronegativity of N atom is greater than that of Cl atom. The characteristic properties of chalcogens and transition metal atoms have been nicely correlated in terms of the computed values of χ of such elements. The evaluated electronegativities of the elements beautifully exhibit the periodic behaviour of periods and groups of the Periodic Table. The revealed internal consistencies suggest that the present effort of introducing a scale of electronegativity based on absolute radius of atoms is largely successful.
The paper was presented in the conference of Theory and Application of Computational Chemistry, Gyeongju, Korea February 15–20, 2004 and the Abstract was published in the Proceedings of the Conference.
