Question

The set of quantum numbers, n = 2, l=2,$m_l$ = 0 :

• A. describes an electron in a 2s orbital
• B. describes one of the five orbitals of a similar type
• C. describes an electron in a 2p orbital
• D. is not allowed

Answer 1

Answer: (D)

is not allowed

Answer 2

The set of quantum numbers $n=2, l=2, m_l=0$ is not allowed because the azimuthal quantum number $l$ must satisfy the condition $0 \le l \le n-1$. For $n=2$, the allowed values for $l$ are $0$ and $1$. Since the given value of $l$ is $2$, which is greater than $n-1=1$, this set of quantum numbers is invalid.