On an episode of the TV program Curb Your Enthusiasm (HBO) I watched recently, Larry David took off on one of his famous stream-of-consciousness digressions – this time about his preference and tendency to use stalls, rather than urinals, when visiting public restrooms.

Interestingly enough (or maybe not), his admission stimulated some electrical impulses and activity in my warped brain that led me to think of Hund’s Rule of Maximum Multiplicity – a topic you must remember from general chemistry class. Of course, this postulate is often referred to as “the bus-seat rule.”

Hund’s Rule describes the process of populating atomic orbitals with electrons – specifically the way those electrons are arranged – as atomic number increases. Quite simply, the rule stipulates that if two electrons have two spaces (i.e., orbitals) to occupy, then they would rather occupy one orbital each rather than “pair up” and occupy just one orbital.

So, for example, take the case of the element Boron which has three “p” orbitals but just one electron in that particular energy level. For argument’s sake, let’s say that that lone electron occupies the p(x) orbital. The next element on the periodic table, Carbon, has the same number of p orbitals (but one more electron than Boron) with one electron in each of the p(x) and p(y) orbitals. And Nitrogen, the next element in line, has three electrons in this energy level, one in each of the p(x), p(y), and p(z) orbitals. Can you visualize this at all? Electrons are distributing themselves among the p orbitals much as passengers on a bus: nobody sits next to someone else unless and until they really have to. So, in the case of Oxygen, yet the next element under consideration, the configuration would have two electrons in p(x) and one each in the other two orbitals. (The two electrons in p(x) are said to be a “lone pair.”)

So, you’re probably wondering where I’m going with this? (If you’re still reading, that is). What does Larry David’s use of stalls have to do with Hund’s Rule and electrons?

Well, actually, hardly anything. It’s just that I’ve been thinking about bathroom behavior myself (remember I’m talkin’ Larry David not Larry Craig kinda stuff here!)…given that last summer, in some of the buildings on campus, new urinals were installed. Our urinals are supposedly the latest in “green” technology – as they are waterless devices that don’t use H₂O to flush with. They actually don’t flush: all in all, not a bad idea to conserve water, and the campus is making points in the community for its conservation efforts.

The thing is, the urinals have been installed with no privacy dividers between them. When you’re standing there doing your business, it’s sort of like lining up at a public trough. And, for me, that’s not the most comfortable situation in the world. What’s the deal here, anyway? We’re already conserving 2.5 million gallons of water per year (!) …do we really have to give up our privacy rights too?

So: this is where the bus-seat rule comes into play. With no dividers between the urinals (hence no privacy) and, I think, many of us modern men having similar reservations about the public-trough concept, what we do is situate ourselves as far apart as possible when we’re in the restroom doing our thing. For example, I’ll walk in and I’m the only one in there. I’ll take the urinal that’s next to the partition separating the sink and the urinal sections. The next guy comes in and will take the urinal that’s tenth (out of ten) in line…around the corner a little bit. If a third person comes in, he’ll take one of the urinals approximately midway between us. And so on.

Given this, doesn’t it seem that our bathroom behavior is a little like seating on a bus or electrons in orbitals? Or, I guess, even other types of human behavior. For example, a blogger named Vishy, in a post from early 2005, observed that Hund’s Rule can also apply to seating ourselves in a cafeteria or taking the elevator.

Not that keeping your distance from others is such a bad thing. Sometimes there are certain activities that are just plain better when performed alone. Hund tells us that the pairing of electrons is an unfavorable process where energy must be expended in order to make it occur. I suggest that the closeness of humans, in some situations, is not the greatest of things either… with there being energetic, emotional and social barriers to making it (i.e., the closeness) happen.

Me? I support the practice of privacy dividers in our public restrooms or, in their absence, maximum multiplicity.