The electrons, identified by quantum number `n` and `l` can be placed in the order of increasing energy from the lowest to highest as :
(1) `n = 4,l=1`
(2) `n = 4, l= 0`
(3) `n = 3 , l= 2`
(4) `n= 3 , l = 1`

Options

A. `(3) lt (4) lt (2) lt (1)`
B. `(4) lt (2) lt (3) lt (1)`
C. `(2) lt (4) lt (1) lt (3)`
D. `(1) lt (3) lt (2) lt (4)`

Answer

B

Explanation

(b) `|(,n,l,"n(suborbit)",n+l),((a),4,1,4p,5),((b),4,0,4s,4),((c),3,2,3d,5),((d),3,1,3p,4)|`
Higher then value of `(n + 1)`, higher is the energy. If `(n + 1)` are same, then suborbit with lower value of `n` has lower energy. Thus,
`3 p lt 4 s lt 3 d lt 4 p`
`(4) lt (2) lt (3) lt (1)`.