Which of the following set of quantum numbers is correct for the $19^{th}$ electron of chromium?
$n$ $l$ $m$ $s$

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 :

What is an orbital? Explain the point and boundary surface diagram of orbitals.

Match the $LIST$-$I$ with $LIST$-$II$:

List-$I$ (Orbital)	List-$II$ (Radial nodes and nodal plane)
$A$. $2s$	$I$. $1$ Radial node + two nodal planes
$B$. $3s$	$II$. $1$ Radial node + one nodal plane
$C$. $3p$	$III$. $2$ Radial nodes + No nodal plane
$D$. $4d$	$IV$. $1$ Radial node + No nodal plane

What is the atomic number of an element whose $M^{2+}$ ion has the electronic configuration $[Ar] \, 3d^8$?

Which of the following orbitals represents $3d_{z^2}$ orbitals?