Question

The correct set of quantum numbers for valence electron of $Rb$ (atomic number $37$ ) is:

• A. $5, 0, 0, - \frac{1}{2}$
• B. $5, 1, 0, \frac{1}{2}$
• C. $6, 0, 1, \frac{1}{2}$
• D. $5, 1, 1, \frac{1}{2}$

Answer 1

Answer: (A)

Electronic configuration of $Rb =[ Kr ] 5 s ^{1}$
$Rb$ is alkali metal with valence electron in $5 s$ subshell.
Hence, $n =5$
For $s$ electron, $1=0$ and $m =0$.
s can have value $\pm \frac{1}{2}$.
Thus, the correct set of quantum numbers for $Rb$ (atomic number $37$ ) is
$5,0,0,-\frac{1}{2}$.