Hydrogen atom has only one electron, So, mutual repulsion between electrons is absent. However, in multielectron atoms mutual repulsion between the electrons is significant. How does this affect the energy of an electron in the orbitals of the same prinicipal quantum number in multielectron atoms?

Explanation

Hydrogen atom is one electron atom. The electron atom. The electronic energy depends upon n. For multi-electron atom, electronic energy takes into account both n and l and is given by (n+l) rule. Ln a given, electron shell having same value of n, the values of l for s, p, d and f orbitals are different. Therefore these have different values. For more details, consult section 2.26.