Curie Notes 14: The Bohr Atom and Energy Levels
Hydrogen gives only four colours of visible light. The reason lies on a ladder of energy inside the atom, and you can climb it with a pencil.
Balmer and Rydberg formulas, Bohr's energy levels E = −13.6 eV/n², emission and absorption, the hydrogen series and ionisation energy, worked step by step.


by Marie Curie 