Z_eff is the net positive charge experienced by an electron in a multi-electron atom. It can be approximated by Slater's rules, considering shielding effects of inner electrons.
| LIST I | LIST II |
|---|---|
| A. Energy of ground state of He | I. \( +6.04 \, \text{eV} \) |
| B. Potential energy of I orbit of H-atom | II. \( -27.2 \, \text{eV} \) |
| C. Kinetic Energy of II excited state of He | III. \( 54.4 \, \text{eV} \) |
| D. Ionization potential of He | IV. \( -54.4 \, \text{eV} \) |