Two nodal planes are present in

Options

A. `pi_(2px)^**`
B. `sigma_(2p_z)`
C. `pi_(2p_x)`
D. `pi_(2p_y)`

Explanation

To determine which molecular orbital has two nodal planes, we will analyze the given options based on their characteristics.

### Step-by-Step Solution:

1. **Understanding Nodal Planes**:
- A nodal plane is a region in a molecular orbital where the probability of finding an electron is zero. In molecular orbitals, the number of nodal planes can be determined by the type of orbital and its symmetry.

2. **Analyzing the Options**:
- **Option A: π* 2px**:
- This is an anti-bonding molecular orbital formed from the combination of p orbitals. The combination results in a molecular orbital with two nodal planes. The nodal planes are located where the wave function changes sign, which occurs in the regions where the orbital overlaps negatively.

- **Option B: σ 2pz**:
- The σ 2pz molecular orbital is a bonding orbital. In this case, there are no nodal planes present. The wave function does not change sign across the entire orbital, indicating that there is no region where the probability of finding an electron is zero.

- **Option C: π 2px and π 2py**:
- Both π 2px and π 2py are bonding orbitals. Each of these orbitals has one nodal plane. The nodal plane is present due to the nature of the p orbitals and their orientation. Therefore, neither of these options has two nodal planes.

3. **Conclusion**:
- The only molecular orbital that has two nodal planes is **π* 2px**. Therefore, the correct answer is **Option A: π* 2px**.

### Final Answer:
The two nodal planes are present in **π* 2px**.

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