Question

The valence shell electronic configuration of $C{r}^{2+}$ ion is :

• A. $4s^{0}3d^4$
• B. $4s^{2}3d^2$
• C. $4s^{2}3d^0$
• D. $3p^{6}4s^2$

Answer 1

The correct option is A $4s^{0}3d^4$

Electronic configuration of chromium
$Cr\to \left[Ar\right]3d^{5}4s^1$
In $C{r}^{2+}$, we have lost 2 electrons.
$C{r}^{2+}\to \left[Ar\right]3d^{4}4s^0.$