fun & games & learning

What I learned in this week's lecture: why atomic orbitals are referred to as s, p, d, and f (and others as appropriate): sharp, principal, diffuse and fundamental, from the series of atomic spectral lines identified in early spectroscopy.


What I relearned in this week's lecture: why (conceptually) the 4s orbital fills before the 3d orbital (because of probability density at the nucleus). Which wasn't even slightly in the lecture materials, but one of my students (there's a whole bunch of TAs, and we're each being sent off into a video conference breakout room with about five of the undergrads in breaks between chunks of lectures) asked the really good question of "is there a [comprehensible] reason for this, or do we just have to take it on trust?"

Rather to my embarrassment I had... completely forgotten the answer, and had to look it up myself, all the while knowing that I had been that student. I'm pretty sure I asked exactly that question, pretty stubbornly, until I got an answer I found satisfying, and then having got it I was happy to go on serenely accepting that that's just how the world worked, and now it's twelve or so years later and, when put on the spot, I had to go "... I'll look that up for you."

So that was dizzying.