In the case of the hydrogen atom (with the assumption that there is no spin-orbit coupling), the observables that commute with Hamiltonian are the orbital angular momentum, spin angular momentum, the sum of the spin angular momentum and orbital angular momentum, and the z components of the above angular momenta. Thus, the good quantum numbers in this case, (which are the eigenvalues of these observables) are l , j , m l , m s , m j . We have omitted s , since it always is constant for an electron and carries no significance as far the labeling of states is concerned.