7. Compare the angular momentum of a ground-state electron in the Bohr model of the
hydrogen atom with its value in the quantum theory.
【sol】
In the Bohr model, for the ground-state orbit of an electron in a hydrogen atom, l = h/mv = 2pr,
and so L = pr = . In the quantum theory, zero-angular-momentum states (y spherically
symmetric) are allowed, and L = 0 for a ground-state hydrogen atom