Number of orbitals in $h$ sub-shell is

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

What is a nodal surface?

Maximum number of electrons in a subshell with $n=4$ and $l=3$ is

Arrange the following in the increasing order of their energy:
$(i)$ $n = 2, l = 0, m_l = 0, m_s = +\frac{1}{2}$
$(ii)$ $n = 2, l = 1, m_l = +1, m_s = -\frac{1}{2}$
$(iii)$ $n = 3, l = 2, m_l = +1, m_s = -\frac{1}{2}$
$(iv)$ $n = 3, l = 1, m_l = -1, m_s = +\frac{1}{2}$

The presence of three unpaired electrons in a nitrogen atom is explained by .......