You can find this empirical problem here with the numbers to be substituted in to the Slater and Hartree-Foch models. The numbers for Ga are here.
https://en.wikipedia.org/wiki/Effective_nuclear_charge
How do I calculate the effective nuclear charges for Ga3+ and Ga?
2 answers
effective nuclear charge measured where?
eff nuc charg= 9 -Number of electrons in the inner shells.
eff nuc charg= 9 -Number of electrons in the inner shells.