The number of angular and radial nodes in $3p$ orbital respectively are

Explain the energy order of orbitals in multielectron atoms.

In a multi-electron system,the energy of an electron of $2p_y$ orbital is :-

Which of the following set of quantum numbers is correct for the $19^{th}$ electron of chromium?
$n$ $l$ $m$ $s$

The correct decreasing order of energy for the orbitals having the following set of quantum numbers:
$A$. $n=3, \ell=0, m=0$
$B$. $n=4, \ell=0, m=0$
$C$. $n=3, \ell=1, m=0$
$D$. $n=3, \ell=2, m=1$

What is the total spin for the electronic configuration of fluorine $(F)$?