[msk034]

Can't get electronegativity concept straight. Consider ClO. For oxygen, electron attachment / detachment energies are >> 1.46/13.31eV, for Chlorine >> 3.62/12.97 eV. I then can assume two hypothetic structures for the ClO compound, say Cl+O- and Cl-O+. The goal is to see which side will be favored in terms of energy. Cl+O- gives >> 1.46 and takes >> 13.31 eV, Cl-O+ >> 3.62 and >>12.97 respectively, overall the first one requires >> + 11.48 eV, and the second >> + 9.99, so Cl-O+ is energetically more favorable than Cl+O-, which is nonsense. What's wrong?

[msk034]

I can try to bring in some QM magic and say elements tend to match their sizes (symmetry sake) and hog the blanket, but this doesn't seem "logical enough".