Question

The set of quantum numbers not applicable for an electron in an atoms is

• A. $n=1, l=1, m_{l}=1, m_{s}=+\frac{1}{2}$
• B. $n=1, l=0, m_{l}=0, m_{s}=+\frac{1}{2}$
• C. $n=2 ,l=1, m_{l}=1, m_{s}=-\frac{1}{2}$
• D. $n=2, l=0, m_{l}=0, m_{s}=+\frac{1}{2}$

Answer 1

Answer: (A)

If $n=1$
then $l=0$, because $l=$ zero to $(n-1)$ any integral value.
So, value of $l$ never be equal to $n$.
$m=-l$ to $+l$ including zero
So, if $l=0, m$ never be equal to $1$
Hence, the given set of quantum number is not applicable.
$n=1, l=1, m_{l}=1, m_{s}=+\frac{1}{2}$