Me: I mean the thing into his head. If the potential energy diagram shows transitions between energy levels. E.g. Na Mg IHB IVB VB VIB VIIB VIIIB IB IIB Al Si P s Cl Al 4 K Ca Sc Ti V Gr m F* Co Ni Cu Zn Gs □e As Se Br Kr 5 fib Sj Y Zr m Mo Tc Ru Rh Pd AO Cd In Sn Sb Te 1 Xe 6 Gs Ba La HI Ta w Re Os Ir Pt Au Hg TI Pb Bi Po At Rn 7 Fr Rd AC Large Radii 3 Ci