Electronegativity Scales

ELECTRONEGATIVITY SCALES Electronegativity get the best is an arbitary denture. They ar establish on various types of experimental selective information like hamper vital force, dipole antenna antenna moment, ionisation potence and electron affinity. Most commonly employ scales are 1. Paulings scale 2. Mullikens scale 3. Sandersons scale 4. Alfred and Rochows scale Paulings scale (1932) This scale is establish on an empirical comparison surrounded by the energy of a attach and the electronegativities of bonded atoms. Consider a bond A-B amongst two confused atoms A and B of a molecule AB. allow the bond energies of A-A, B-B and A-B bonds be represented as EA-A, EB-B and EA-B respectively. It may be seen that the bond dissociation energy of A-B is to the highest degree higher than the geometric plastered of the bond dissociation energies of A-A and B-B bonds i.e., A B A A B B E E E ? ? ? > ? Their contrariety (?) is related to the difference in the electronegativities of A and B harmonize to the by-line equation A B A A B B E E E ? ? ? ? ? ? 2 A B (X ?X ) (or) 0.208 ? = XA XB Here, XA and XB are the electronegativities of A and B respectively. The factor 0.208 arises from the transformation of Kcals to electron volt. Considering arbitarily the electronegativity of heat content to be 2.1, Pauling calculated electronegativities of a nonher(prenominal) elements with the athletic supporter of this equation.

outrage of Pauling scale The disadvantage of Paulings scale is that bond energies are not known with any degree of accuracy for many comforting elements. Problem numerate the electronegativity of chlorine from the side by side(p) data EH-H = 104 K cal mol-1 ; ECl-Cl = 36 K cal mol-1 EH-Cl= 134 K cal mol-1 According to Paulings equation HCl H H Cl Cl _ E E ? E ? ? ? _ 134 ? 104?36 = 134 61.18 = 72.82 Cl H 0.208 _ X ?X X X 0.208 72.82 Cl H ? ? = 1.77 xcl - 2.1 = 1.77 [ XH = 2.1] XCl = 1.77 + 2.1 = 3.87 2. Mullikens Scale In 1934, Mulliken suggested an alternative attempt to electronegativity based on ionization energy...If you exigency to get a bounteous essay, order it on our website: Ordercustompaper.com

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