Paramagnetic substances must contain .....

The maximum number of electrons that can be filled in the shell with the principal quantum number $n=4$ is

An element in $+2$ oxidation state has $24$ electrons. The atomic number of the element and the number of unpaired electrons in it respectively are

$A$ certain orbital has $n = 4$ and $m_{L} = -3$. The number of radial nodes in this orbital is .......... (Round off to the Nearest Integer).

The electronic configuration of three elements $A$,$B$,and $C$ are given below. Stable form of $A$ may be represented by the formula:
$A : 1s^2, 2s^2, 2p^6$
$B : 1s^2, 2s^2, 2p^6, 3s^2, 3p^3$
$C : 1s^2, 2s^2, 2p^6, 3s^2, 3p^5$

$1s^2 2s^2 2p^6 3s^2$ is the electronic configuration of the metal