Consider the following set of quantum numbers.

	n	$\mathcal{l}$	$m_{\mathcal{l}}$
A.	3	3	-3
B.	3	2	-2
C.	2	1	+1
D.	2	2	+2

The number of correct sets of quantum numbers is____________.

n = 1, 2, 3 …….;   $\mathcal{l}=0$ ……. to n – 1, $m_{\mathcal{l}}=\mathcal{l}.......0......+\mathcal{l}$  

A. n = 3   $\mathcal{l}=3$ $m_{\mathcal{l}}=-3$  is incorrect as $\mathcal{l}$  can not be equal to n.

B. n = 3   $\mathcal{l}=2$   $m_{\mathcal{l}}$ = -2 is correct set.

C. n = 2   $\mathcal{l}=1$ $m_{\mathcal{l}}$ = +2 is incorrect set as  $\mathcal{l}$ can not be equal to n.

So; correct set of quantum numbers is B and C.