Which of the following are degenerate orbitals?
$3d_{xy}, 4d_{xy}, 3d_{z^2}, 3d_{xz}, 4d_{yz}, 4d_{z^2}$

The shape of $s$-orbital is

Arrange the energy of the $2s$ orbital for hydrogen,lithium,sodium,and potassium in increasing order.

The maximum number of electrons in an atom with $l = 2$ and $n = 3$ is

Arrange the electrons represented by the following sets of quantum numbers in the decreasing order of energy.
$(i) \ n = 4, l = 0, m_l = 0, m_s = +\frac{1}{2}$
$(ii) \ n = 3, l = 1, m_l = 1, m_s = -\frac{1}{2}$
$(iii) \ n = 3, l = 2, m_l = 0, m_s = +\frac{1}{2}$
$(iv) \ n = 3, l = 0, m_l = 0, m_s = -\frac{1}{2}$

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: