Which is true in the case of `[Ni(CO)_4]` complex?

Options

A. (a) All are correct
B. (b) Tetrahedral shape of the molecule
C. (c) Hybridization of `Ni` is `sp^3`
D. (d) Diamagnetic

Explanation

To determine the true statements regarding the complex `[Ni(CO)₄]`, we will analyze its properties step by step.

### Step 1: Identify the oxidation state of Nickel in `[Ni(CO)₄]`
- The carbonyl ligand (CO) is a neutral ligand, meaning it does not contribute any charge to the complex.
- Therefore, the oxidation state of Nickel (Ni) in `[Ni(CO)₄]` is 0.

**Hint:** Remember that neutral ligands do not affect the oxidation state of the metal they are coordinated to.

### Step 2: Determine the electron configuration of Nickel
- Nickel has an atomic number of 28. Its electron configuration is:
- Ni: [Ar] 3d⁸ 4s²
- In the case of `[Ni(CO)₄]`, since Ni is in the 0 oxidation state, it retains its full electron configuration.

**Hint:** The oxidation state of the metal is crucial for determining its electron configuration.

### Step 3: Analyze the hybridization of `[Ni(CO)₄]`
- The coordination number of `[Ni(CO)₄]` is 4, which typically leads to sp³ hybridization.
- In this case, the 4s and 4p orbitals will be involved in hybridization. The 3d orbitals are fully filled and do not participate in hybridization.

**Hint:** Coordination number helps in predicting the hybridization and geometry of the complex.

### Step 4: Determine the geometry of the complex
- Since the hybridization is sp³, the geometry of the complex will be tetrahedral.

**Hint:** The type of hybridization can often be correlated with the geometry of the complex.

### Step 5: Assess the magnetic properties of `[Ni(CO)₄]`
- All electrons in `[Ni(CO)₄]` are paired due to the strong field nature of the CO ligand.
- Therefore, the complex is diamagnetic.

**Hint:** The presence of unpaired electrons determines whether a complex is paramagnetic or diamagnetic.

### Conclusion
Based on the analysis, the following statements are true for the complex `[Ni(CO)₄]`:
1. The oxidation state of Nickel is 0.
2. The hybridization is sp³.
3. The geometry is tetrahedral.
4. The complex is diamagnetic.