The Bohr model is a neat but quite imperfect depiction of the inner workings of an atom before things got too muddled up by quantum principles.

Niels Bohr's model of the hydrogen atom—first published 100 years ago and commemorated in a special issue of Nature—is simple, elegant, revolutionary, and wrong. Well, "wrong" isn't exactly ...

But instead of solving the Bohr-model problem, Hagen applied the “variational principle” – a technique usually reserved for approximating quantum-mechanical systems that cannot be solved analytically ...