Identify the element from the following having six unpaired electrons in its observed electronic configuration.

In an atom, the order of increasing energy of electrons with quantum numbers $(i)$ $n=4, l=1$, (ii) $n=4, l=0$, (iii) $n=3, l=2$, and (iv) $n=3, l=1$ is:

How many electrons can be accommodated in a sub-shell for which $n = 3, l = 1$?

Which of the following statement$(s)$ is/are wrong?

Correct statements for an element with atomic number $9$ are:
$A.$ There can be $5$ electrons for which $m_{s}=+\frac{1}{2}$ and $4$ electrons for which $m_{s}=-\frac{1}{2}$
$B.$ There is only one electron in $p_z$ orbital
$C.$ The last electron goes to an orbital with $n=2$ and $l=1$
$D.$ The sum of angular nodes of all the atomic orbitals is $1$
Choose the correct answer from the options given below:

Choose the pair whose ions have the similar electronic configuration.