Quantum numbers $l = 2$ and $m = 0$ represent which orbital?

The atom of the element having atomic number $14$ should have:

The four quantum numbers for the valence shell electron of Sodium $(Z=11)$ are:

Given:
$(A)\ n = 5, m_l = +1$
$(B)\ n = 2, l = 1, m_l = -1, m_s = -1/2$
The maximum number of electron$(s)$ in an atom that can have the quantum numbers as given in $(A)$ and $(B)$ are respectively:

The correct ground state electronic configuration of chromium atom is

Explain $(n + l)$ rules for the energy of an orbital with an example.