Which of the following species must have maximum number of electrons in '`d_(xy)'` orbital?

Options

A. Cr
B. `Fe^(3+)`
C. `Cu^(+)`
D. Both (a) and (b)

Answer

To determine which species has the maximum number of electrons in the `d_(xy)` orbital, we need to analyze the electronic configurations of the given species. Let's go through the steps one by one.

### Step 1: Identify the electronic configurations of the given species.

1. **Chromium (Cr)**:
- Atomic number: 24
- Electronic configuration: `Ar 3d^5 4s^1`
- In the `d` orbital, the distribution is:
- `d_(xy)`: 1 electron
- Other `d` orbitals: 4 electrons distributed among the remaining orbitals.

2. **Iron (Fe) +3 (Fe³⁺)**:
- Atomic number: 26
- Electronic configuration: `Ar 3d^6 4s^2`
- For Fe³⁺, we remove 3 electrons (2 from 4s and 1 from 3d):
- Configuration for Fe³⁺: `Ar 3d^5`
- In the `d` orbital, the distribution is:
- `d_(xy)`: 1 electron
- Other `d` orbitals: 4 electrons distributed among the remaining orbitals.

3. **Copper (Cu) + (Cu⁺)**:
- Atomic number: 29
- Electronic configuration: `Ar 3d^{10} 4s^1`
- For Cu⁺, we remove 1 electron from 4s:
- Configuration for Cu⁺: `Ar 3d^{10}`
- In the `d` orbital, the distribution is:
- `d_(xy)`: 2 electrons (since all `d` orbitals are filled).
- Other `d` orbitals: 8 electrons distributed among the remaining orbitals.

### Step 2: Compare the number of electrons in the `d_(xy)` orbital.

- **Chromium (Cr)**: 1 electron in `d_(xy)`
- **Iron (Fe³⁺)**: 1 electron in `d_(xy)`
- **Copper (Cu⁺)**: 2 electrons in `d_(xy)`

### Step 3: Conclusion

From the analysis, we can conclude that **Copper (Cu⁺)** has the maximum number of electrons in the `d_(xy)` orbital, which is **2 electrons**.

### Final Answer:
The species with the maximum number of electrons in the `d_(xy)` orbital is **Cu⁺**.

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