Which one of the following has maximum number of nodal planes ? .

Options

A. `sigma^(**)1s`
B. `sigma^(**)2p_(z)`
C. `pi2p_(x)`
D. `pi^(**)2p_(y)`

Explanation

To determine which molecular orbital has the maximum number of nodal planes, we will analyze each of the given molecular orbitals step by step.

### Step 1: Understanding Nodal Planes
Nodal planes are regions 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.

### Step 2: Analyze Sigma Star 1s
- The sigma star 1s molecular orbital is formed by the destructive interference of two 1s atomic orbitals.
- This molecular orbital has **1 nodal plane**.

### Step 3: Analyze Anti-Sigma 2pz
- The anti-sigma 2pz molecular orbital is formed by the destructive interference of two 2pz atomic orbitals.
- This orbital also has **1 nodal plane**.

### Step 4: Analyze Pi 2px
- The pi 2px molecular orbital is formed by the constructive interference of two px orbitals.
- This molecular orbital has **1 nodal plane** located along the internuclear axis.

### Step 5: Analyze Pi Star 2py
- The pi star 2py molecular orbital is formed by the destructive interference of two 2py atomic orbitals.
- This molecular orbital has **2 nodal planes** (one along the y-axis and one along the x-axis).

### Conclusion
After analyzing all the given molecular orbitals, we find:
- Sigma star 1s: 1 nodal plane
- Anti-sigma 2pz: 1 nodal plane
- Pi 2px: 1 nodal plane
- Pi star 2py: 2 nodal planes

Thus, the molecular orbital with the maximum number of nodal planes is **Pi star 2py**, which has **2 nodal planes**.

### Final Answer
**D. Pi star 2py has the maximum number of nodal planes.**