Which of the following is not correct for electronic distribution in the ground state?

Options

A.
B.
C.
D.

Answer

To solve the question of which electronic distribution in the ground state is not correct, we need to analyze the electronic configurations of the given elements: cobalt, nickel, copper, and zinc.

### Step-by-Step Solution:

1. **Identify the Atomic Numbers and Electronic Configurations**:
- **Cobalt (Co)**: Atomic number = 27
- Electronic configuration: \( \text{[Ar]} \, 4s^2 \, 3d^7 \)
- **Nickel (Ni)**: Atomic number = 28
- Electronic configuration: \( \text{[Ar]} \, 4s^2 \, 3d^8 \)
- **Copper (Cu)**: Atomic number = 29
- Electronic configuration: \( \text{[Ar]} \, 4s^1 \, 3d^{10} \)
- **Zinc (Zn)**: Atomic number = 30
- Electronic configuration: \( \text{[Ar]} \, 4s^2 \, 3d^{10} \)

2. **Analyze Each Electronic Configuration**:
- For **Cobalt**: The configuration \( \text{[Ar]} \, 4s^2 \, 3d^7 \) is correct.
- For **Nickel**: The configuration \( \text{[Ar]} \, 4s^2 \, 3d^8 \) is correct.
- For **Copper**: The configuration \( \text{[Ar]} \, 4s^1 \, 3d^{10} \) is correct. (Note: Copper has a unique configuration where one electron from the 4s subshell is promoted to the 3d subshell to achieve a fully filled d subshell.)
- For **Zinc**: The configuration \( \text{[Ar]} \, 4s^2 \, 3d^{10} \) is correct.

3. **Determine the Incorrect Configuration**:
- Upon reviewing the configurations, all configurations are correct except for the one for Copper, which is often mistakenly written as \( \text{[Ar]} \, 3d^{9} \, 4s^2 \). However, the correct configuration is indeed \( \text{[Ar]} \, 4s^1 \, 3d^{10} \).

4. **Conclusion**:
- The electronic distribution that is not correct for the ground state is for **Copper (Cu)**, as it is commonly misrepresented. The correct answer is **Copper**.

### Final Answer:
The electronic distribution that is not correct for the ground state is for **Copper (Cu)**.