Question

Which of the following sets of quantum numbers is correct for an electron in $4f-$ orbital?

• A. $n=4,l=3,m=+4,s=-\frac{1}{2}$
• B. $n=4,l=3,m=-4,s=-\frac{1}{2}$
• C. $n=4,l=3,m=+1,s=+\frac{1}{2}$
• D. $n=4,l=3,m=-5,s=-\frac{1}{2}$

Answer 1

The correct option is C $n=4,l=3,m=+1,s=+\frac{1}{2}$

Principal quantum number = n
Azimuthal quantum number $l$ ranges from 0 to $n-1$
Magnetic quantum number m ranges from $-l$ to $+l$
For $4f,n=4,l=3m=-3,-2,-1,0,+1,+2,+3$
$s=-\frac{1}{2}$ or $+\frac{1}{2}$
From the given options, $n=4,l=3,m=+1$ and
$s=+\frac{1}{2}$ is correct.