Which of the following statement is not correct from the view point of molecular orbital theory?

Options

A. `Be_(2)` is not a stable molecule .
B. `He_(2)` is not stable of `N_(2)` is maximum amongst the homonuclear diatomic molecules belonging to the second period .
C. Bond strength of `N_(2)` is maximum amongst the homonuclear diatomic molecules belonging to the second period.
D. The order of energies of molecular orbitals in `N_(2)` molecule is ` sigma 2s lt sigma^(***) 2s lt sigma2p_(z) lt (pi 2p_(x) = pi 2p_(y)) lt (pi^(***) 2p_(x) = pi^(***) 2p_(y)) lt sigma^(***) 2p_(z)`

Explanation

To determine which statement is not correct from the viewpoint of molecular orbital theory, we will analyze each statement provided in the question.

### Step-by-Step Solution:

1. **Understanding Molecular Orbital Theory**:
- Molecular Orbital (MO) theory explains the formation of molecular orbitals from atomic orbitals. It helps in predicting the stability, bond order, and magnetic properties of molecules.

2. **Analyzing the Statements**:
- **Statement A**: "BE2 is not stable."
- According to MO theory, the bond order of BE2 is calculated as follows:
- Bond Order = (Number of bonding electrons - Number of antibonding electrons) / 2
- BE2 has 2 electrons in bonding orbitals and 2 in antibonding orbitals, resulting in a bond order of 0. Thus, this statement is correct.

- **Statement B**: "He2 is also not stable."
- For He2, the bond order is also 0 (2 bonding electrons and 2 antibonding electrons). Therefore, this statement is correct as well.

- **Statement C**: "N2 is maximum amongst the homo-nuclear diatomic molecules belonging to the second period."
- The bond order of N2 is 3 (6 bonding electrons and 3 antibonding electrons). This is indeed the highest bond order among second-period diatomic molecules, making this statement correct.

- **Statement D**: "The order of energy of molecular orbitals in N2 is incorrect."
- The correct order of molecular orbitals for N2 is:
- σ(1s) < σ*(1s) < σ(2s) < σ*(2s) < σ(2p) < π(2p) < π*(2p) < σ*(2p)
- If the order stated in the question differs from this, then this statement is incorrect.

3. **Conclusion**:
- After analyzing all statements, we find that Statement D is the one that is not correct according to molecular orbital theory.

### Final Answer:
- The statement that is not correct from the viewpoint of molecular orbital theory is **Statement D**.