The effective nuclear charge is
Zeff = Z - S
where Z = # protons in the nucleus and S = shielding effect of electrons
Slater's rule is used to determine the value of S [for electrons in either s- or p- AO only; see link for electrons in d- or f- AO ]
i. write the electron configuration of the atom in terms of ascending principle quantum number, i.e. electron shell (it does not follow the aufbau principle)
ii. S = 0.35 (# valence electrons - 1) + 0.85 (# electrons in next lower electron shell) + # remaining electrons
ex. for As, 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p3
Zeff = Z - S = 33 - {0.35 (5 - 1) + 0.85 (18) + 10} = 6.3
HWproblem: using Slater's rule, what is the effective nuclear charge of Mg, P, & As [6 points]