Question
Which of the following is not permissible arrangement of electrons in an atom?
-
n = 4, l=0, m=0, s=-1/2
-
n=5, l=3, m=0, s=+1/2
-
n=3, l=2, m=-3, s= -1/2
-
n=3, l=2, m=-2, s=-1/2
Solution
C.
n=3, l=2, m=-3, s= -1/2
For an electron, n may be 0,1, 2....and l=0 to n=-1 and m = - l to l (including 0) and 
1/2.
Hence, If ,
n=3,
l=0 to (3-1)
=0,1,2
m=-l to+l
=-2,-1,0, +1,+2
s 
1/2
