Question

$\begin{array}{cc}\text{Column - 1}& \text{Column - 2}\\ Species& Characteristics\\ \left(A\right)C{o}^{3+}(Z=27)& \left(p\right)\text{Total number of fully filled orbitals is nine.}\\ \left(B\right)S{c}^{3+}(z=21)& \left(q\right)\text{The value of magnetic moment (spin only) is greater than or equal to 3.87 BM.}\\ \left(C\right)C{r}^{3+}(Z=24)& \left(r\right)\text{Number of electrons with}n+l=3\text{is eight.}\\ \left(D\right)N{i}^{2+}(Z=28)& \text{(s) Number of electrons with (m = 0) may be either 11 or 12.}\\ & \text{(t) No unpaired electron.}\end{array}$

• A. [A - q, r, s] [B - p, r, t]; [C - p, q, r, s]; [D - r, s].
• B. [A - q, r] [B - p, r, t]; [C - p, q, r, s]; [D - r, s].
• C. [A - q, r, s] [B - p]; [C - p, q, r, s]; [D - r, s].
• D. [A - q, r, s] [B - p, r, t]; [C - p, q, r, s]; [D - r, s].

Answer 1

The correct option is A [A - q, r, s] [B - p, r, t]; [C - p, q, r, s]; [D - r, s].

(A) $C{o}^{3+}:1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^6$
so no. of fully filled orbitals is $10$.
no. of unpaired electrons = $4$.
So, magnetic moment is greater than $3.87$.
no. of electrons with $(n+l)=3$.
i.e. $3s,2p$ are eight.
no. of electrons with $m=0$ may be $11or12$.

(B) $S{c}^{3+}:1s^{2}2s^{2}2p^{6}3s^{2}3p^6$
no. of fully filled orbitals is $9$.
no. of unpaired electrons $0$.
no. electrons with $(n+l)=3$.
i.e. $3s,2p$ are $8$.
no. of electrons with $m=0$ are $10$.

(C) $C{r}^{3+}:1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^3$
no. of fully filled orbitals is $9$.
no. of unpaired electrons = $3$.
no. electrons in $3s$ and $2p$ are $8$.
no. of electrons with $m=0$ may be $11$.

(D) $N{i}^{2+}:1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^8$
no. of fully filled orbitals is $12$.
no. of unpaired electrons = $2$.
no. electrons in $3s$ and $2p$ is $8$.
no. of electrons with $m=0$ may be $11$ or $12$.