AX is a covalent diatomic molecule where A and X are second row elements of periodic table. Based on — Chemical Bonding Chemistry Question

💡 Solution & Explanation

**Step 1: Identify the bond order formula** Bond order = (Number of bonding electrons - Number of antibonding electrons) / 2 Given: Bond order = 2.5 **Step 2: Set up the equation** Let total electrons = n 2.5 = (Bonding electrons - Antibonding electrons) / 2 5 = Bonding electrons - Antibonding electrons Also: Bonding electrons + Antibonding electrons = n **Step 3: Solve the system of equations** From the two equations: - Bonding electrons - Antibonding electrons = 5 - Bonding electrons + Antibonding electrons = n Adding these equations: 2 × Bonding electrons = n + 5 Bonding electrons = (n + 5) / 2 Subtracting: 2 × Antibonding electrons = n - 5 Antibonding electrons = (n - 5) / 2 **Step 4: Apply constraints for second-row elements** For a second-row diatomic molecule, electrons fill orbitals: σ1s, σ*1s, σ2s, σ*2s, π2p, π2p, σ2p, π*2p, π*2p, σ*2p Both A and X are second-row elements (period 2). Testing n = 15: - Bonding electrons = (15 + 5) / 2 = 10 - Antibonding electrons = (15 - 5) / 2 = 5 - Bond order = (10 - 5) / 2 = 2.5 ✓ Therefore, the answer is 15.00.