If molecular axis is Z then which of the following overlaping is not possible

Options

A. `P_(z)+p_(z) =sigma` bond
B. `p_(x)+p_(y) =pi` bond
C. `p_(x) +p_(x) =pi` bond
D. `p_y+p_(y)=pi` bond

Answer

To determine which type of overlapping is not possible when the molecular axis is the Z-axis, we can analyze the types of orbitals involved in the overlapping process.

### Step-by-step Solution:

1. **Identify the Molecular Axis**:
- The molecular axis is given as the Z-axis. This means that any overlapping must be considered in relation to this axis.

2. **Types of Orbitals**:
- We have different types of orbitals: s, px, and py.
- The s orbital is spherical, while the px and py orbitals are oriented along the x and y axes, respectively.

3. **Overlapping Scenarios**:
- **s and px Overlap**:
- The s orbital can overlap with the px orbital. This overlap is possible and results in the formation of a sigma bond.
- **s and py Overlap**:
- The s orbital can also overlap with the py orbital. This overlap is also possible and results in the formation of a sigma bond.
- **px and py Overlap**:
- The px and py orbitals are oriented perpendicular to each other. When the Z-axis is the internuclear axis, there is no direct overlap between these two orbitals, leading to zero overlap. This means that they cannot form a bond in this orientation.

4. **Conclusion**:
- The overlapping that is not possible when the Z-axis is the molecular axis is between the px and py orbitals.

5. **Final Answer**:
- The answer to the question is that the overlapping between **px and py** is not possible when the molecular axis is the Z-axis.