Delocalization and resonance 3 2.3. Hybrid orbital theory 3 2.4. Molecular orbital theory 2.4.1. molecular orbital diagram (H2 molecule) 3 2.4.2. molecular orbital diagram (N2 and O2 molecules) 3 2.4.3. bond orders in O2, O2–, O2+ 3 2.4.4. unpaired electrons and paramagnetism 3 3. ...