Question

Anomalous electronic configuration in the $3\mathrm{d}$ series are of

• A. $\mathrm{Cu}\mathrm{and}\mathrm{Zn}$
• B. $\mathrm{Cr}\mathrm{and}\mathrm{Fe}$
• C. $\mathrm{Fe}\mathrm{and}\mathrm{Cu}$
• D. $\mathrm{Cr}\mathrm{and}\mathrm{Cu}$

Answer 1

The correct option is D

$\mathrm{Cr}\mathrm{and}\mathrm{Cu}$

The correct option is (D):

Explanation for the correct answers:

$\mathrm{Cr}\mathrm{and}\mathrm{Cu}$:

1. Chromium ($\mathrm{Cr}$) and $\left(\mathrm{Cu}\right)$ are the exceptions of the $3\mathrm{d}$ transition series which will show the anomalous electric configuration.
2. $\mathrm{Cr}$ and $\mathrm{Cu}$ basically attain the extra stability of the half-filled and the full-filled electronic configuration by the changing of expected pattern of electric configuration.
3. The Electronic configuration of $\mathrm{Cr}$ is: $\left[\mathrm{Ar}\right]3{\mathrm{d}}^{5}4{\mathrm{s}}^1$
4. The Electronic configuration of $\mathrm{Cu}$ is: $\left[\mathrm{Ar}\right]3{\mathrm{d}}^{10}4{\mathrm{s}}^1$
5. So, in both the cases an electron from the $4\mathrm{s}$ orbital jumps to the $3\mathrm{d}$ subshell as it is more stable due to the half-filled and full-filled stable configuration.

Explanation for the incorrect options:

Option (A): $\mathrm{Cu}\mathrm{and}\mathrm{Zn}$

1. Electronic configuration for: $\mathrm{Cu}$ is $\left[\mathrm{Ar}\right]3{\mathrm{d}}^{10}4{\mathrm{s}}^1$
2. Electronic configuration for $\mathrm{Zn}$is: $\left[\mathrm{Ar}\right]3{\mathrm{d}}^{10}4{\mathrm{s}}^2$
3. Anomalous electronic configuration in $3\mathrm{d}$ series is of $\mathrm{Cu}$ and not $\mathrm{Zn}$.
4. Hence, this option is incorrect.

Option (B): $\mathrm{Cr}\mathrm{and}\mathrm{Fe}$

1. Electronic configuration for $\mathrm{Cr}$ is $\left[\mathrm{Ar}\right]3{\mathrm{d}}^{5}4{\mathrm{s}}^1$
2. Electronic configuration for $\mathrm{Fe}$ is $\left[\mathrm{Ar}\right]3{\mathrm{d}}^{6}4{\mathrm{s}}^2$
3. Hence, this option is incorrect.

Option (C): $\mathrm{Fe}\mathrm{and}\mathrm{Cu}$

1. Electronic configuration for $\mathrm{Fe}$ is $\left[\mathrm{Ar}\right]3{\mathrm{d}}^{6}4{\mathrm{s}}^2$
2. Electronic configuration for $\mathrm{Cu}$ is $\left[\mathrm{Ar}\right]3{\mathrm{d}}^{10}4{\mathrm{s}}^1$
3. Anomalous electronic configuration in $3\mathrm{d}$ series is of $\mathrm{Cu}$ and not $\mathrm{Fe}$.
4. Hence, this option is incorrect.

Therefore, the correct option is (D): $\mathrm{Cr}\mathrm{and}\mathrm{Cu}$