Chemistry - Atomic Structure Question with Solution | TestHub

Electronic configuration of
$\text{Ar}\text{ : }1{\text{s}}^2\text{,}2{\text{s}}^{2}2{\text{p}}^6\text{,}3{\text{s}}^{2}3{\text{p}}^6$

Therefore, quantum numbers for last electron are$n=3\&l=1,$so$n+l=4$