Which of the following is the correct plot for the probability density $\psi^{2}(r)$ as a function of distance '$r$' of the electron from the nucleus for $2s$ orbital?

Which set of quantum numbers is correct for the valence electron of $Na$?

The wave function $(\Psi)$ of $2s$ is given by
$\Psi_{2s} = \frac{1}{2\sqrt{2\pi}} \left(\frac{1}{a_0}\right)^{3/2} \left(2 - \frac{r}{a_0}\right) e^{-r/2a_0}$
At $r = r_0$,a radial node is formed. Thus,$r_0$ in terms of $a_0$ is:

Given below are two statements:
Statement $I$ : For a given shell,the total number of allowed orbitals is given by $n^2$.
Statement $II$ : For any subshell,the spatial orientation of the orbitals is given by $-l$ to $+l$ values including zero.
In the light of the above statements,choose the correct answer from the options given below:

The set of orbitals filled just after the filling of electrons in an atom with atomic number $Z = 56$ is:

The energy required to remove an electron from different subshells of a $H$ atom is given below. What is the order of these energies?