In this paper, we have introduced the mean orbital radii of valence electrons (~n~l) into the electronegativity scale function for the first time and adopted a new way to determine the effective nuclear charge number (Z'). A new electronegativity scale defined as Z'/~n~l is proposed. The new scale bears a good linearship to the Mulliken electronegativity and has in general the same periodic trends with the Pauling scale, except on some specific aspects the new scale acts more like a property of an isolate atom than the Pauling's. Because the new scale relates closely to the Mulliken scale and in a sence can stand for the average nuclear potential of the valence electrons, obvious and reliable physical meanings contribute to it. Also, the new scale is theoretically calculable. The calculated results for 72 elements were presented and many detailed discussions were given.

Key words: SCALE, ELECTRONEGATIVITY, ORBITS, ELECTRIC CHARGE NUMBER, EFFECTIVE NUCLEAR CHARGE