The sum of the number of angular nodes and radial nodes for a $4d$ orbital is:

Arrange the following orbitals in decreasing order of energy:
$A$. $n = 3, l = 0, m = 0$
$B$. $n = 4, l = 0, m = 0$
$C$. $n = 3, l = 1, m = 0$
$D$. $n = 3, l = 2, m = 1$
The correct option for the order is:

The energy of atomic orbitals in a given shell follows the order:

Select the correct statements for quantum numbers.
$(i)$ Magnetic quantum number $(m_l)$ gives information about the spatial orientation of orbitals with respect to the standard set of coordinate axes.
$(ii)$ Electron spin quantum number is represented by '$s$' and has values of $\pm \frac{1}{2}$.
$(iii)$ Principal quantum number $(n)$ determines the size of the orbitals and also,to a large extent,the energy of the orbitals.

The number of radial nodes in a $2s$ orbital is equal to that in a ........ orbital.

The ground state energy of a hydrogen atom is $-13.6 \ eV$. Consider an electronic state $\Psi$ of $He^+$ whose energy,azimuthal quantum number,and magnetic quantum number are $-3.4 \ eV$,$2$,and $0$ respectively. Which of the following statement$(s)$ is(are) true for the state $\Psi$?
$(1)$ It has $2$ angular nodes
$(2)$ It has $3$ radial nodes
$(3)$ It is a $4d$ state
$(4)$ The nuclear charge experienced by the electron in this state is less than $2e$,where $e$ is the magnitude of the electronic charge.