Passage II

In an atom, an electron exists in one of several quantum states (configurations). Each quantum state can be specified by a set of numbers. Two of these numbers are called n and j. In addition, each quantum state is associated with a type of orbital (a region surrounding the nucleus).

The figure shows, for n ≤ 4 in a hydrogen atom, every possible combination of n and j for which a quantum state exists. The figure also shows, for each state, the energy—which is determined by the values of n and j—and the orbital type: s, p, d, or f.