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

Given below are two statements :
Statement $I$ : $A$ spectral line will be observed for a $2p_x \rightarrow 2p_y$ transition.
Statement $II$ : $2p_x$ and $2p_y$ are degenerate orbitals.
In the light of the above statements,choose the correct answer from the options given below :

In an argon atom,how many electrons have $m_{\ell} = 1$?

Two electrons $A$ and $B$ in an atom have the following set of quantum numbers:
$A: n=3, l=2, m_l=-2, m_s=+1/2$
$B: n=3, l=0, m_l=0, m_s=+1/2$
What is true for $A$ and $B$?

Which of the following combination of statements is true regarding the interpretation of the atomic orbitals?
$1$. An electron in an orbital of high angular momentum stays further away from the nucleus than an electron in an orbital of lower angular momentum.
$2$. For a given value of the principal quantum number,the size of the orbit is inversely proportional to the azimuthal quantum number.
$3$. According to wave mechanics,the ground state angular momentum is equal to $\frac{h}{2\pi}$.
$4$. The plot of $\Psi$ vs $r$ for various azimuthal quantum numbers shows peak shifting towards higher $r$ values.

What is meant by electronic configuration?