The number of unpaired electrons in `Ni (CO)_(4)` is

Options

A. 0
B. 2
C. 3
D. 4

Answer

To determine the number of unpaired electrons in Ni(CO)₄, we can follow these steps:

### Step 1: Determine the electronic configuration of Nickel (Ni)
Nickel has an atomic number of 28. The electronic configuration of Ni is:
\[ \text{Ni: } [Ar] 3d^8 4s^2 \]

### Step 2: Identify the ligand and its effect
CO (carbon monoxide) is a strong field ligand. Strong field ligands cause pairing of electrons in the d-orbitals.

### Step 3: Analyze the coordination complex
In the complex Ni(CO)₄, nickel is in a +0 oxidation state because CO is a neutral ligand. Therefore, the electronic configuration remains as:
\[ \text{Ni: } [Ar] 3d^8 4s^2 \]

### Step 4: Consider the pairing of electrons
When strong field ligands like CO are present, they cause the electrons in the 4s and 3d orbitals to pair up. In the presence of CO, the electrons will fill the 3d orbitals completely before any unpaired electrons can exist.

### Step 5: Write the new electronic configuration
Due to the strong field effect of CO, the electrons will pair up in the 3d orbitals:
\[ \text{New configuration: } [Ar] 3d^{10} \]
This indicates that all d-orbitals are filled with paired electrons.

### Step 6: Count the number of unpaired electrons
Since all the electrons are paired in the 3d orbitals, the number of unpaired electrons in Ni(CO)₄ is:
\[ \text{Number of unpaired electrons} = 0 \]

### Final Answer
The number of unpaired electrons in Ni(CO)₄ is **0**.

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