The electrons identified by the following quantum numbers `n` and `l: (i) n = 4, l = 1, (ii) n = 4, l = 0, (iii) n = 3, l = 2`, and (iv) `n = 3, l = 1` can be placed in the order of increasing enegry from the lowest to the highest as

Options

A. `(iii) lt (i) lt (iv) lt (ii)`
B. `(i) lt (iii) lt (ii) lt (iv)`
C. `(ii) lt (iv) lt (i) lt (iii)`
D. `(iv) lt (ii) lt (iii) lt (i)`

Answer

D

Explanation

According to `(n +l)` rule, the electroc with lower `(n +l)` has lower enegry. Thus, (ii) and (iv) `(n +l = 4)` have lower enegry than (i) and (iii) `(n +l = 5)`. If two `e^(-)s` have same `(n +l)` value, then `e^(-)` of lower `n` has lower enegry. Thus, (iv) has lower enegry than (ii), while (iii) has lower enegry than (i)`.