Q. Which of the following sets of quantum number is correct for an electron in $4f$-orbital?
A) $n = 4,\ l = 3,\ m = + 4,\ s = + 1/2$
B) $n = 4,\ l = 4,\ m = - 4,\ s = - 1/2$
C) $n = 4,\ l = 3,\ m = + 1,\ s = + 1/2$
D) $n = 3,\ l = 2,\ m = - 2,\ s = + 1/2$
Explanation
(c)
Any sub-orbit is represented as $nl$ such that $n$ is the principal quantum number (in the form of values) and $l\$is the azimuthal quantum number (its name).
Value of $l < n,\ l:0\ 1\ 2\ 3\ 4$
s$\ p\ d\ f\ g$
Value of $m: - l,\ldots\ldots\ldots.0,\ldots\ldots + l$
Value of $s: + \frac{1}{2}or - \frac{1}{2}$
Thus, $for\ 4f:n = 4,\ l = 3,\ m =$ any value between -3 to +3.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.