Which of the following `MOs` has more than one nodal plane?

Options

A. `pi 2p_(y)`
B. `sigma 2s`
C. `pi^(**) 2p_(y)`
D. `sigma^(**) 2p_(z)`

Explanation

To determine which molecular orbital (MO) has more than one nodal plane, we will analyze each option provided in the question. A nodal plane is a region in a molecular orbital where the probability of finding an electron is zero.

### Step-by-Step Solution:

1. **Understanding Nodal Planes**:
- A nodal plane is defined as a plane where the wave function of the molecular orbital is zero, indicating no electron density. The number of nodal planes can help differentiate between bonding and antibonding molecular orbitals.

2. **Analyzing Option A: Pi 2Py**:
- The Pi 2Py molecular orbital is formed by the side-by-side overlap of two 2Py orbitals.
- Since it is a bonding orbital, it has one nodal plane between the two lobes of the orbital.
- **Conclusion**: Pi 2Py has **1 nodal plane**.

3. **Analyzing Option B: Sigma 2s**:
- The Sigma 2s molecular orbital is formed by the head-on overlap of two 2s orbitals.
- The 2s orbital is spherical, and when two 2s orbitals overlap, there are no nodal planes present.
- **Conclusion**: Sigma 2s has **0 nodal planes**.

4. **Analyzing Option C: Pi star 2Py**:
- The Pi star 2Py molecular orbital is formed by the side-by-side overlap of two 2Py orbitals in an out-of-phase manner (antibonding).
- This results in two nodal planes due to the destructive interference of the wave functions.
- **Conclusion**: Pi star 2Py has **2 nodal planes**.

5. **Analyzing Option D: Sigma star 2Pz**:
- The Sigma star 2Pz molecular orbital is formed by the head-on overlap of two 2Pz orbitals in an out-of-phase manner (antibonding).
- This results in one nodal plane between the two lobes of the orbital.
- **Conclusion**: Sigma star 2Pz has **1 nodal plane**.

### Final Conclusion:
Among the options analyzed, **Option C: Pi star 2Py** is the only molecular orbital that has more than one nodal plane (specifically, it has 2 nodal planes).