Question

which of the following quantum number sets describes a 4f orbital?
n=3, l=1, ml= -1
n=2, l=0, ml= 0
n=3, l=2, ml= -1
n=4, l=3, ml= +2
n=4, l=2, ml= +1

Explanation:

• Principal quantum number ($n$): Represents the energy level or shell. For a $4f$ orbital, $n = 4$ (since the first number in the orbital notation is the principal quantum number).
• Azimuthal quantum number ($l$): Determines the sub - shell. For an $f$ sub - shell, $l=3$ (where $l = 0$ is $s$, $l = 1$ is $p$, $l = 2$ is $d$, and $l = 3$ is $f$).
• Magnetic quantum number ($m_l$): Ranges from $-l$ to $+l$. When $l = 3$, $m_l$ can be $- 3,-2,-1,0,+1,+2,+3$.

Answer:

n = 4, l = 3, ml= + 2