Question

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

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

Answer 1

Answer: (B)

$12$ and $5$

The electronic configuration of Cr along with the values of the quantum numbers $n$ and $l$ are shown.

	$n$	$l$
$1s^2$	$1$	$0$
$2s^2$	$2$	$0$
$2p^6$	$2$	$1$
$3s^2$	$3$	$0$
$3p^6$	$3$	$1$
$3d^5$	$3$	$2$
$4s^1$	$4$	$0$

Thus the number of electrons with $l=1$ is $12$
and the number of electrons with $l=2$ is $5$