The effective atomic number of `Fe` in `Fe(CO)_(5)` is

Options

A. `26`
B. `34`
C. `36`
D. `54`

Explanation

To find the effective atomic number (EAN) of iron (Fe) in the complex Fe(CO)₅, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Atomic Number of Iron (Fe)**:
- The atomic number (Z) of iron (Fe) is 26.

2. **Determine the Oxidation State of Iron in the Complex**:
- In the complex Fe(CO)₅, carbon monoxide (CO) is a neutral ligand, meaning it does not contribute to the charge of the complex. Therefore, the oxidation state of iron (Fe) is 0.

3. **Identify the Coordination Number**:
- The coordination number (CN) is the number of ligand atoms that are bonded to the central metal atom. In this case, there are 5 carbon monoxide ligands attached to iron, so the coordination number is 5.

4. **Use the EAN Formula**:
- The formula for calculating the effective atomic number (EAN) is given by:
\[ \text{EAN} = Z - \text{oxidation number} + 2 \times \text{coordination number} \]
- Plugging in the values we have:
\[ \text{EAN} = 26 - 0 + 2 \times 5 \]

5. **Calculate the Effective Atomic Number**:
- Performing the calculations:
\[ \text{EAN} = 26 + 10 = 36 \]

6. **Conclusion**:
- The effective atomic number of Fe in Fe(CO)₅ is 36.

### Final Answer:
The effective atomic number of Fe in Fe(CO)₅ is **36**.

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