Question

Which of the following paramagnetic ions would exhibit magnetic moment (Spin only) of the order 5 BM? (Atomic number Mn = 25, Cr = 24, V = 23, Ti = 22)

• A. $V^{2+}$
• B. $T{i}^{2+}$
• C. $M{n}^{+2}$
• D. $C{r}^{2+}$

Answer 1

The correct option is D $C{r}^{2+}$

Configuration of ,

$V^{2+}\left[Ar\right]4s^{0}3d^3$ $n=3$

$T{i}^{2+}\left[Ar\right]4s^{0}3d^2$ $n=2$

$M{n}^{2+}\left[Ar\right]4s^{0}3d^5$ $n=5$

$C{r}^{2+}\left[Ar\right]4s^{0}3d^4$ $n=4$

Hence spin moment of $C{r}^{2+}=\sqrt{4(4+2)}\simeq 4.92BN\simeq 5BM$