Electron Configurations Continued
Let's see...the fourth element, beryllium (Be), has a second electron in the
higher energy level, which means that level now has both a spin up and a spin
down. So the next element should begin a third energy level--is that right?
See for yourself. Try clicking on boron (B), the fifth element--you know, the
one Bruce Willis was so excited about.
Hey, what's going on? The fifth electron has a slightly higher energy than
the other yellow ones, but it's not directly above them; it's in that column
Ah. Do you have any ideas about what might be happening?
Well...my best guess is that the colored rows, pink and yellow, represent the
main energy levels, and s, p, and d are like smaller sublevels of them.
Very good. So what do you think is going to happen as you keep
going along that row of the periodic table?
Hmm...carbon (C) has a second electron in the p column, so now s and p in the
yellow row each have a spin up and a spin down. The next electron must start
a whole new energy level, or maybe it goes into the d column, if that's the
next higher sublevel.
Sounds very logical...but now look at nitrogen (N).
Hey, the seventh electron went into the p column too! How can there be three
with the same energy?
It gets worse. Go on.
Oxygen (O), fluorine (F), neon (Ne)--more electrons just keep getting stuffed
into that same state. What happened to the exclusion principle? This makes
no sense at all!
It makes perfect sense, once you know the rules.