1. Chapter 9(c) Covalent Bonding: Orbitals (contd)

2. Figure 9.26: (a) The molecular orbital energy- level diagram for the H 2 molecule. (b) The shapes of the molecular orbitals are obtained by squaring the wave functions for MO 1 and MO 2.

3. Figure 9.27: Bonding and antibonding molecular orbitals (MOs).

4. Figure 9.28: A molecular orbital energy-level diagram for the H 2 molecule.

5. Copyright © Houghton Mifflin Company. All rights reserved.9c–5 Figure 9.29: The molecular orbital energy- level diagram for the H 2 - ion.

6. Copyright © Houghton Mifflin Company. All rights reserved.9c–6 Figure 9.30: The molecular orbital energy- level diagram for the He 2 molecule.

7. Copyright © Houghton Mifflin Company. All rights reserved.9c–7 Figure 9.31: The relative sizes of the lithium 1s and 2s atomic orbitals.

8. Copyright © Houghton Mifflin Company. All rights reserved.9c–8 Figure 9.32: The molecular orbital energy- level diagram for the Li 2 molecule.

9. Copyright © Houghton Mifflin Company. All rights reserved.9c–9 Figure 9.33: (a) The three mutually perpendicular 2p orbitals on two adjacent boron atoms. Two pairs of parallel p orbitals can overlap as shown in (b) and (c), and the third pair can overlap head-on as shown in (d).

10. Copyright © Houghton Mifflin Company. All rights reserved.9c–10 Figure 9.34: (a) The two p orbitals on the boron atom that overlap head-on produce two s molecular orbitals, one bonding and one antibonding. (b) Two p orbitals that lie parallel overlap to produce two p molecular orbitals, one bonding and one antibonding.

11. Copyright © Houghton Mifflin Company. All rights reserved.9c–11 Figure 9.35: The expected molecular orbital energy-level diagram resulting from the combination of the 2p orbitals on two boron atoms.

12. Figure 9.36: The expected molecular orbital energy- level diagram for the B 2 molecule.