The effective atomic number of iron in `[Fe(CN)_(6)]^(3-)` is

Options

A. `34`
B. `36`
C. `37`
D. `35`

Explanation

To find the effective atomic number (EAN) of iron in the complex ion \([Fe(CN)_{6}]^{3-}\), we can follow these steps:

### Step 1: Determine the Atomic Number of Iron
The atomic number of iron (Fe) can be found on the periodic table.
- **Atomic number of Fe = 26**

### Step 2: Determine the Oxidation State of Iron
To find the oxidation state of iron in the complex, we need to consider the charge of the complex and the ligands involved. The cyanide ion (CN) has a charge of -1. Since there are 6 cyanide ions, their total contribution to the charge is:
- Total charge from ligands = \(6 \times (-1) = -6\)

The overall charge of the complex ion \([Fe(CN)_{6}]^{3-}\) is -3. We can set up the following equation to find the oxidation state (x) of iron:
\[ x + (-6) = -3 \]
Solving for x:
\[ x - 6 = -3 \\ x = -3 + 6 \\ x = +3 \]
- **Oxidation state of Fe = +3**

### Step 3: Calculate the Effective Atomic Number (EAN)
The formula for calculating the effective atomic number (EAN) is:
\[ EAN = Z - n + 2m \]
Where:
- \(Z\) = Atomic number of the metal (Fe)
- \(n\) = Oxidation state of the metal
- \(m\) = Number of ligands

Substituting the values we have:
- \(Z = 26\) (atomic number of Fe)
- \(n = +3\) (oxidation state of Fe)
- \(m = 6\) (number of CN ligands)

Now, substituting these values into the formula:
\[ EAN = 26 - 3 + 2 \times 6 \]
Calculating:
\[ EAN = 26 - 3 + 12 \\ EAN = 26 - 3 + 12 = 35 \]

### Conclusion
The effective atomic number of iron in \([Fe(CN)_{6}]^{3-}\) is **35**.

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