Effective atomic number of the central metal ion, Pt, in the complex `[Pt(NH_(3))_(6)]^(4+)` is , ( the atomic no. of Pt is 78)

Options

A. 74
B. 90
C. 86
D. 84

Explanation

To find the effective atomic number (EAN) of the central metal ion, Pt, in the complex \([Pt(NH_3)_6]^{4+}\), we can use the formula:

\[ \text{Effective Atomic Number (EAN)} = Z - \text{Oxidation Number} + 2 \times \text{Coordination Number} \]

Where:
- \(Z\) is the atomic number of the metal.
- The oxidation number is the charge on the metal in the complex.
- The coordination number is the number of ligands bonded to the metal.

### Step-by-Step Solution:

1. **Identify the Atomic Number (Z) of Platinum (Pt)**:
- The atomic number of Pt is given as 78.
\[ Z = 78 \]

2. **Determine the Oxidation Number of Platinum in the Complex**:
- The complex ion \([Pt(NH_3)_6]^{4+}\) has an overall charge of +4.
- Ammonia (NH₃) is a neutral ligand, contributing 0 to the charge.
- Let the oxidation number of Pt be \(X\).
- The equation for the charge balance is:
\[ X + 0 = +4 \implies X = +4 \]

3. **Identify the Coordination Number**:
- The coordination number is the number of ligands attached to the central metal ion.
- In this case, there are 6 ammonia ligands.
\[ \text{Coordination Number} = 6 \]

4. **Substitute Values into the EAN Formula**:
\[ \text{EAN} = Z - \text{Oxidation Number} + 2 \times \text{Coordination Number} \]
\[ \text{EAN} = 78 - 4 + 2 \times 6 \]

5. **Calculate the EAN**:
- First, calculate \(2 \times 6\):
\[ 2 \times 6 = 12 \]
- Now substitute back into the EAN formula:
\[ \text{EAN} = 78 - 4 + 12 \]
\[ \text{EAN} = 78 + 8 = 86 \]

### Final Answer:
The effective atomic number of the central metal ion, Pt, in the complex \([Pt(NH_3)_6]^{4+}\) is **86**.

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