The Concept of Electronegativity (EN)
Defined as the relative ability of a bonded atom to attract
shared electrons (not the same as EA)
Bond energy of H2 = 432 kJ/mol
Bond energy of F2 = 159 kJ/mol
Bond energy of HF = 565 kJ/mol, not 296 kJ/mol
The stronger-than-expected HF bond is due to unequal
sharing of electrons, with F bearing a partial negative
charge and H bearing a partial positive charge. The
attraction between the partial charges strengthens the
bond.
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