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atomic theory

Modeling Classic Atomic Theory I: Where do Element Masses Come From?

Paul Price | Mon, 09/29/2025 - 08:42

What if your students derived the periodic table’s masses before they ever learned about moles? This piece reframes “classic” atomic theory as a data-driven approach to building O:C ratios, uncovering the law of definite proportions, and explaining why oxygen’s relative mass is 16 when carbon's is 12. The result is a historically grounded, quantitative model of Dalton’s ideas that makes atomic theory feel discovered—not delivered.

Analogy Experiment—Projectile Pennies with Rutherford

Ben Meacham | Mon, 11/08/2021 - 15:48

Atomic theory is a common topic throughout any introductory chemistry course. It is likely that Rutherford’s gold foil experiment gets at least some attention in your course. This simple activity gives students an opportunity to replicate Rutherford’s experiment through an analogy experiment that may allow for easier conceptualization of the experiment itself and provide additional support for model development.

Analogy Experiment—Projectile Pennies with Rutherford

Ben Meacham | Mon, 03/11/2019 - 12:18

Atomic theory is a common topic throughout any introductory chemistry course. It is likely that Rutherford’s gold foil experiment gets at least some attention in your course. I have used a simple activity that gives students an opportunity to replicate Rutherford’s experiment through an analogy experiment that may allow for easier conceptualization of the experiment itself and provide additional support for model development.

The Atomic Dashboard

Doug Ragan | Mon, 09/22/2014 - 18:25

If you are on Twitter and follow #chemchat, you may have recently seen some beautiful, rotating 3D atomic and molecular models from Dave Doherty @atomsNMolecules. I was curious about these models and after contacting Dave, he introduced me to The Atomic Dashboard.

Using Orbital Viewer

Tom Kuntzleman | Tue, 12/03/2013 - 15:54

Orbital Viewer is a fantastic program for displaying electronic orbitals. It is a great resource for teaching students about orbital shapes and the rules, nomenclature and notation of the quantum numbers n, l and m.