Like many AP Chemistry teachers, I was not fond of teaching Photoelectron Spectroscopy (PES). Surprisingly, I fell in love with teaching PES in AP Chemistry this year after I made an old-school change.
After spending the start of the year using a modified version of the Modeling Instruction curriculum (density and physical properties, followed by gas laws, followed by energy and phase changes), we don’t actually start talking about what’s inside atoms until December. I love that by this point students are already familiar with some of the habits of mind needed to reason abstractly about atoms -- thinking proportionally, explaining macroscopic observations at the particle level -- and we are ready to layer on both more abstraction and the symbolic level. By January, we are ready to explore electron configurations.
“You sank my battleship!” Do you remember this line from a classic commercial featuring the board game Battleship? It sat in my family’s game closet when I was a kid, but it’s popping up again recently, with chemistry twists.
We’ve all seen and use the so-called Aufbau Diagram. It is a mnemonic used to remember the order of “filling” of atomic orbitals during the construction of the ground state electron configurations of the elements. The presentation of this diagram is largely disconnected from any physical meaning. Here’s what we tell our students: “Memorize the diagram, learn to use it, and you’re guaranteed to get the right answer.”