But if you are talking about Le Chatelier's principle, we are probably talking about cases similar to buffers here.
Although small changes can be resisted, large changes (predictions) will eventually allow us to predict the paper.
My guess using Year 11 Chemistry:
The first ionisation energy of non-metals are very large, unlike that of metals. Hence it is difficult for electrons to be raised to a higher energy level by absorption of radiations because their energies are not sufficient.
(Keeping in mind that in the...