The total number of orbitals present for principal quantum number,$n=4$ is

The shape of $d_{xy}$ orbital will be

Given below are the quantum numbers for $4$ electrons.
$A. \; n = 3, l = 2, m_l = 1, m_s = +1/2$
$B. \; n = 4, l = 1, m_l = 0, m_s = +1/2$
$C. \; n = 4, l = 2, m_l = -2, m_s = -1/2$
$D. \; n = 3, l = 1, m_l = -1, m_s = +1/2$
The correct order of increasing energy is

The orientation of an atomic orbital is given by ........ .

The correct set of four quantum numbers for the valence electron of rubidium atom $(Z=37)$ is:

Write a note about the energy of orbitals in hydrogen.