Question

Which of the following is incorrect as per rules for Linear Combination of Atomic Orbitals (LCAO)?

• A. The atomic orbitals overlap as much as possible
• B. Overlap of orbitals has to be as low as possible
• C. The atomic orbitals should be of same energy
• D. Symmetry of two atomic orbitals must remain unchanged or both change symmetry in the same manner

Hint:

Maximum overlap → stronger bond. LCAO requires same energy, proper symmetry, and large overlap.

Answer 1

The Correct Option is B

Step 1: LCAO principle.
Molecular orbitals are formed by linear combinations of atomic orbitals. For effective bonding: - The overlap must be maximum (to increase electron density between nuclei).
- Orbitals must have the same or nearly same energy.
- Symmetry of combining orbitals must be compatible.
Step 2: Incorrect statement.
Statement (2) contradicts the rule because greater overlap leads to stronger bonds, not lower overlap.
Final Answer: \[ \boxed{\text{Overlap of orbitals has to be as low as possible}} \]