For an electron with quantum numbers $s = +1/2$ and $m_l = -1$,which of the following orbitals is not possible?

The electronic configuration $1s^{2}\, 2s^{2}\, 2p^{5}\, 3s^{1}$ represents:

Which statement is not correct for $n = 5$,$m = +3$?

$A$ certain orbital has no angular nodes and two radial nodes. The orbital is

Electrons should be filled in orbitals according to their increasing order of energy. This statement is related to .....

$A$ 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 principal quantum number in multielectron atoms?