Chlorine ground state electronic configuration

PROBLEM 5.18 What is a likely ground-state electron configuration for the sodium ion, Na +, formed by loss of an electron from a neutral sodium atom What is a likely ground-state electron configuration for the chloride ion, Cl-, formed by adding an electron to a neutral chlorine atom ... 

In our previous experience with chlorine [4], for which the ground state valence configuration is the same as that in Ar II, 3s 3p, we found that all the excited configurations in which one of the 3p electrons is promoted to an upper n p or n d ( > 3) state comply with the LS scheme. This was valid for two different states of the core, the ground, P, and the excited D states. The same has been found to occur in Ar 11. However, in some of the states where one 3p electron is promoted to an orbital with higher n and / quantum numbers the levels showed a clear JJ structure. We observed that for a given value of / this was more obvious the higher the principal quantum... 

Figure 5.12 Radial wavefunctions P /r) with n = 3 for neutral chlorine (Cl I), singly-ionized argon (Aril), and doubly-ionized potassium (Kill) which demonstrate the collapse of the 3d orbital (all these systems have the electron configuration ls22s22p63s23p5 in the ground state while the results apply to the. .. 3s23p4( D)3d 2S states). Note that the horizontal scales are slightly different, but the distance from the origin to (3s + 3p)/2 is the same in all three cases. It is the average position 3s and , i.e., the 3d orbital is clearly uncollapsed. The opposite is true for Kill where the 3d orbital has clearly collapsed. The 3d orbital of Aril falls between these two cases. From [SHa83].

In order of increasing energy, the outermost orbitals associated only with the C=S chromophore are (cr), ( )> (71), (n), (tc ), and (cr ), where n is the thiocar-bonyl nonbonding orbital, and n a second nonbonding orbital, (chlorine orbitals are excluded). The electronic configuration of the ground state can be written (a)2(nr)2(n)2(n)2(n )0(a )0, where each of the inner orbitals are doubly occupied by an electron pair and the outer orbitals (virtual) are empty. 

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