1. Write the ground-state electronic configuration of chromium

For chromium, $Z=24$.

Due to the extra stability of half-filled $d$-subshell, the ground-state configuration is:

$\text{Cr} = [\text{Ar}]\,3d^5 4s^1$

Expanded form:

$1s^2\,2s^2\,2p^6\,3s^2\,3p^6\,3d^5\,4s^1$

2. Relate azimuthal quantum number $l$ to subshells

• $l=0 \Rightarrow s$
• $l=1 \Rightarrow p$
• $l=2 \Rightarrow d$

So we need the number of electrons in:

• all $p$-subshells for $l=1$
• all $d$-subshells for $l=2$

3. Count electrons with $l=1$ ($p$-electrons)

The occupied $p$-subshells are:

• $2p^6$
• $3p^6$

Total $p$-electrons:

$6+6=12$

So, number of electrons with $l=1$ is:

$12$

4. Count electrons with $l=2$ ($d$-electrons)

The occupied $d$-subshell is:

• $3d^5$

Total $d$-electrons:

$5$

So, number of electrons with $l=2$ is:

$5$

5. Match with the options

The required pair is:

$(12,\,5)$

This corresponds to Option B.

6. Comparison with stored correct answer

Stored correct answer: B

Our derived answer: B

They match.