Question

Consider the ground state of $Cr$ atom ($Z=24$). The numbers of electrons with azimuthal quantum numbers, $\ell =1$ and $2$, are respectively:

• A. $12$ and $4$
• B. $12$ and $5$
• C. $16$ and $4$
• D. $16$ and $5$

Answer 1

The correct option is B $12$ and $5$

Electronic configuration of $Cr$ ($Z=24$)	$n$	$l$
$1s^2$	$1$	$0$
$2s^2$	$2$	$0$
$2p^6$	$2$	$1$
$3s^2$	$3$	$0$
$3p^6$	$3$	$1$
$3d^5$	$3$	$2$
$4s^1$	$4$	$0$

Thus, the number of electrons with $l=1$ are $12$ and $l=2$ are $5$.