what sets xenon and krypton apart from the other noble gasses that enables them to have higher electronegativites?
Or, more likely, the only acceptable answer is "that's what you get when you measure/calculate, possible explanations are too handwavy to make sense".So if you can't find an answer, maybe it has not been solved yet...
Of course they have. E.g. Mulliken's EN can be derived from measured electron affinities and ionisation energies, seeNoble gases do not have electro negativity.