Multiple-Electron Atoms None of the e eclipsed:Zef=Z 0 One e eclipsed:Zef =Z-1 On Average,Zeft<Z How Much Less Zeff Z Determines Atomic Properties IV-6On Average, Zeff < Z How Much Less Zeff < Z Determines Atomic Properties Multiple-Electron Atoms None of the e- eclipsed: Zeff = Z One e- eclipsed: Zeff = Z - 1 IV-6