Question

An atom Cr has one 4s electron and five 3d electrons. How many unpaired electrons would be in $C{r}^{3+}$?

• A. 1
• B. 2
• C. 3
• D. 4

Answer 1

Answer: (C)

3

$Cr:\left[Ar\right]3d^{5}4s^1$

$C{r}^{+3}:\left[Ar\right]3d^3$

Number of unpaired electrons in $C{r}^{+3}$ is 3.

Option C is correct.