The `pi^(**)` molecular orbital has ________ nodal planes.

Explanation

To determine the number of nodal planes in the `pi^(**)` molecular orbital, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Terminology**:
- The notation `pi` refers to a type of molecular orbital that is formed from the lateral overlap of p orbitals. The `*` (star) indicates that it is an anti-bonding molecular orbital, denoted as `pi*`.

2. **Identify the Nature of `pi*` Orbital**:
- The `pi*` molecular orbital is an anti-bonding orbital. Anti-bonding orbitals are characterized by having a nodal plane where the probability of finding an electron is zero.

3. **Determine the Number of Nodal Planes**:
- For a `pi*` molecular orbital, there are two nodal planes. This is because the anti-bonding nature of the orbital creates regions where the wave functions cancel each other out, resulting in nodes.

4. **Conclusion**:
- Therefore, the `pi*` molecular orbital has **two nodal planes**.

### Final Answer:
The `pi^(**)` molecular orbital has **two nodal planes**.

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