Which of the following molecular orbitals has maximum number of nodal planes ?

Options

A. `sigma^(**)1s`
B. `sigma^(**)2p_(z)`
C. `pi^() 2p_(x)`
D. `pi^(**) 2p_(y)`

Explanation

To determine which molecular orbital has the maximum number of nodal planes, we will analyze the given molecular orbitals: σ* 1s, σ* 2pz, π 2px, and π* 2py.

### 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. The number of nodal planes is an important characteristic of molecular orbitals.

2. **Analyzing σ* 1s Orbital**:
- The σ* 1s orbital is formed from the overlap of two 1s atomic orbitals.
- It has one nodal plane at the center where the electron density is zero.
- **Nodal Planes in σ* 1s**: 1 nodal plane.

3. **Analyzing σ* 2pz Orbital**:
- The σ* 2pz orbital is formed from the overlap of two 2pz atomic orbitals.
- Similar to the σ* 1s, it also has one nodal plane at the center.
- **Nodal Planes in σ* 2pz**: 1 nodal plane.

4. **Analyzing π 2px Orbital**:
- The π 2px orbital is formed from the overlap of two 2px atomic orbitals.
- This orbital has one nodal plane between the two lobes, where there is no electron density.
- **Nodal Planes in π 2px**: 1 nodal plane.

5. **Analyzing π* 2py Orbital**:
- The π* 2py orbital is formed from the overlap of two 2py atomic orbitals.
- This orbital also has one nodal plane between the two lobes.
- **Nodal Planes in π* 2py**: 1 nodal plane.

6. **Conclusion**:
- After analyzing all the given orbitals, we find that σ* 1s, σ* 2pz, π 2px, and π* 2py each have 1 nodal plane.
- However, the question asks for the molecular orbital with the maximum number of nodal planes. Since none of the listed orbitals exceed 1 nodal plane, we conclude that they all have the same number of nodal planes.

### Final Answer:
All the listed molecular orbitals (σ* 1s, σ* 2pz, π 2px, and π* 2py) have the same number of nodal planes, which is 1.