Egg cartons and small objects such as milk jug caps or plastic eggs can be used to illustrate chemical concepts. The egg cartons can be cut into trays to represent atoms or to represent energy levels associated with atomic orbitals. The plastic caps or eggs distributed among the dimples of the trays can be used to represent electrons or pairs of electrons.
Here is a quick and easy yet powerful experiment for para and diamagnetism that helps to provide evidence for quantum numbers.
Many novice students struggle to see elements' valence electron configuration trends across the rows and columns on the periodic table. There are many diagrams and explanations available as resources for students however, a deeper understanding may be possible when students discover these trends independently through a game called Electron Configuration Battleship.
Card sorts can be used to quickly assess student understanding. The author has modified two card sorts on photoelectron spectroscopy and intermoleculer forces for use either remotely or in a paperless classroom.
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.
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.”
A complete understanding of why each element has a particular electronic configurations is a very complex subject. Even so, some confusion regarding the electronic configurations of the elements may be alleviated by looking at the physical properties of the electronic orbitals.