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

Options

A. one
B. two
C. three
D. zero

Answer

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

### Step 1: Determine the oxidation state of nickel in Ni(CO)₄
In Ni(CO)₄, carbon monoxide (CO) is a neutral ligand. Therefore, the oxidation state of nickel (Ni) is 0.

### Step 2: Write the electron configuration of nickel
Nickel (Ni) has an atomic number of 28. Its electron configuration is:
\[ \text{Ni: } [\text{Ar}] 3d^8 4s^2 \]

### Step 3: Analyze the effect of the ligand on the electron configuration
CO is a strong field ligand, which means it can cause pairing of electrons. In the presence of CO, the 4s electrons will pair with the 3d electrons.

### Step 4: Pair the electrons
When CO coordinates with Ni, the 4s electrons will pair with the 3d electrons. The electron configuration will effectively become:
\[ \text{Ni: } [\text{Ar}] 3d^{10} \]
This indicates that all the 3d electrons are paired.

### Step 5: Count the number of unpaired electrons
Since all the electrons in the 3d subshell are paired, there are no unpaired electrons in Ni(CO)₄.

### Conclusion
The number of unpaired electrons in Ni(CO)₄ is 0.

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