Atomic Structure

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:

Step 1: Definition of isotopes.
Isotopes are atoms of the same element that have the same atomic number (same protons) but different mass numbers (different neutrons).
Step 2: Analyze options.
- (1) Wrong: mass number differs in isotopes.
- (2) Correct: atomic number is identical (same element).
- (3) Wrong: nucleon number (mass number) differs.
- (4) Wrong: neutrons differ.
Final Answer: