Question

Among the following series of transition metal ions, how many metals ions have $d^2$ electronic configuration
$F{e}^{4+},V^{3+},S{n}^{2+},A{u}^{3+},T{i}^{2+},A{s}^{3+},C{r}^{3+},M{n}^{5+},C{o}^{3+},Z{r}^{2+},C{d}^{2+},M{o}^{4+},L{a}^{2+},T{a}^{4+},C{o}^{6+},N{i}^{4+}$

Answer 1

Answer: 5

$T{i}_{22}=3d^{2}4s^2$ ; $T{i}^{2+}=3d^2$
$V_{\text{23}}=3d^{3}4s^2$ ; $V^{3+}=3d^2$
$C{r}_{24}=3d^{5}4s^1$ ; $C{r}^{3+}=3d^3$
$M{n}_{25}=3d^{5}4s^2$ ; $M{n}^{5+}=3d^2$
$Z{r}_{40}=4d^{2}5s^2$ ; $Z{r}^{2+}=4d^2$
$M{o}_{42}=4d^{5}5s^1;M{o}^{4+}=4d^2$