Work out bohr model energy levels instantly with clear inputs, formula shown and shareable results.
The Bohr model gives hydrogen-like energy levels as -13.606 Z^2/n^2 eV. Hydrogen's ground state is -13.606 eV, and the n = 2 level sits at -3.401 eV, so 3.4 eV ionises an excited atom against 13.6 eV for the ground state. Orbit radius grows as n^2 and shrinks with Z, which is why heavy ions are so compact.
Energy levels
E(n) = -13.606 Z^2 / n^2 eV
Orbit radius
r(n) = 0.0529 n^2 / Z nm
Because a bound electron sits below the free-electron zero. The magnitude is the energy needed to liberate it.
Only for one-electron systems - hydrogen, He+, Li2+ and so on. Multi-electron atoms need quantum mechanics with electron repulsion.