From Citizendium, the Citizens' Compendium
Now why couldn't Prof. Schubert have put it it this way in 1966?
I like this. Admittedly, my initial sort-of-physical-chemistry class didn't have much in the way of mathematical prerequisites, and we went around muttering aufbau. Still, this is quite readable. Howard C. Berkowitz 16:27, 3 July 2009 (UTC)