1. Pauli principle

2. Wolfgang Pauli and Niels Bohr study spin

5. Σ ∆ l = ±1 ∆ S = 0

6. Σ ∆ l = ±1 ∆ S = 0

10. H2H2

12. H2H2

13. He 2

14. He 2 + ion.

15. H 2 + ion

16. H 2 - ion

17. The relative sizes of the lithium 1s and 2s atomic orbitals

18. Li 2

19. The three mutually perpendicular 2p orbitals on tow adjacent boron atoms.

20. The two p oribitals on the boron atom that overlap head-on combine to form bonding and antibonding orbitals.

21. The expected MO energy-level diagram for the combination of the 2 P orbitals on two boron atoms.

22. The expected MO energy-level diagram for the B 2 molecule

23. The correct MO energy-level diagram for the B 2 molecule.

24. The MO energy-level diagrams, bond orders, bond energies, and bond lengths for the diatomic molecules, B 2 through F 2.

25. An apparatus used to measure the paramagnetism of a sample

26. When liquid oxygen is poured into the space between the poles of a strong magnet, it remains there until it boils away. Source: Donald Clegg

27. The MO energy-level diagram for the NO molecule

28. The MO energy-level diagram for both the NO+ and CN- ions

29. A partial MO energy-level diagram for the HF molecule

30. The electron probability distribution in the bonding MO of the HF molecule

36. + ↓