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Mistake Master · AP Physics 2 · Unit 15 · Step-Through Animation

A List, Not a Ramp

You'll learnthat hydrogen's allowed states are a list with nothing in between, that the atom grows as n squared while its binding fades as one over n squared, and that a closing electron wave is what writes the list.

An electron does not slide between energy levels — the atom is on one rung, then another, and one photon carries the difference. What picks the rungs is a wave that has to close on itself. Eleven short steps; press Next for each one.

11 STEPS · 6 QUICK CHECKS · A LIST WITH NOTHING BETWEEN · THE WAVE MUST CLOSE · v2

the states are a list · farther out is more weakly bound · the wave must close
Before you start
What you're looking at
Hydrogen's energy levels drawn to scale, a jump between two of them, and an electron wave running round a circular orbit.
The question
What happens between two levels, and what decides which orbits are allowed at all?
Step 1 / 11