Energy of atomic orbitals in multielectron system

[keep@science]

although the distance from the nucleus and shielding effect [due to more angular volume] is more for 4s orbital than a 3d orbital ,but yet the energy for a 3d orbital is more than 4s orbital, why?

 

[Simon Bridge]

Welcome to PF;
You mean as in:

It is due to angular momentum and spin.
http://antoine.frostburg.edu/chem/senese/101/electrons/faq/4s-3d.shtml

 

[DrDu]

http://www.quimica.ufpr.br/edulsa/c...w_to_tell_the_orbitals_from_wavefunctions.pdf