Five valence electrons of $P^{15}$ are labelled as $\boxed{AB}_{3s} \,\boxed{X|Y|Z}_{3p}$. If the spin quantum numbers of $B$ and $Z$ are $+\frac{1}{2}$,the group of electrons with three of the quantum numbers $(n, l, m)$ the same are:

How many electrons in an atom may have the following quantum numbers?
$(a)$ $n=4, m_{s}=-\frac{1}{2}$
$(b)$ $n=3, l=0$

If other factors remain the same,the ionization energy required to remove an electron from which of the following orbitals will be the highest?

Match List-$I$ with List-$II$ :

List-$I$ (Quantum number)	List-$II$ (Orbital)
$a. n=2, \ell=1$	$i. 2s$
$b. n=3, \ell=2$	$ii. 3s$
$c. n=3, \ell=0$	$iii. 2p$
$d. n=2, \ell=0$	$iv. 3d$

Choose the correct answer from the options given below :

Identify the correct statements:
a) In an atom,the maximum number of electrons with $n=4$ and $m_s=+\frac{1}{2}$ is $16$.
b) There are $4$ subshells associated with $n=5$.
c) $n=2, l=1, m_l=0$ and $m_s=-\frac{1}{2}$ is a possible set of quantum numbers.
d) The number of radial nodes for $3s$ orbital is $2$.

Identify an orbital with the quantum numbers $n=4, \ell=3, m=0$.