The quantum numbers of electrons are given below. Arrange them in order of increasing energies . Do any of these combinations have same energy ?
a) `n=4,l=2,m_(l)=-2,m_(s)=+1//2`
b) `n=3,l=2,m_(l)=-1,m_(s)=-1//2`
c)`n=4,l=1,m_(l)=0,m_(s)=+1//2`
d) `n=3,l=1,m_(l)=-1,m_(s)=-1//2`

Explanation

Rule :
(1) The relative energy of an electron is given by its (n + l) value . M and s contributions very little.
2 ) If two electrons have the same (n+l) value , electron with lower n value has lower energy.
a) n = 4 , l = 2 (n+l) value = 6
b) n = 3 , l = 2 (n+l) value = 5
c) n = 4 , l = 1 (n+l) value = 5
d) n = 3 , l = 1 (n+l) value = 4
Increasing order of energies of electrons os : `(4)lt (2)lt(3)lt(1)`