• The outermost (valence) electron of sodium is in a 3s state when the atom is in its grou...

• The outermost (valence) electron of sodium is in a 3s state when the atom is in its ground state (Table 10.2 in Section 10.7). The valence electron can be excited to higher levels, the first few of which are shown in Fig. 1. Given the selection rule that only those transitions for which Δl = ±1 are allowed, indicate on this energy-level diagram all allowed transitions among the levels shown.

FIGURE 1

Some low-lying levels of any one electron in sodium.