5. The forces at work are: Electromagnetic: Repulsion of like charges: proton-proton and electron-electron Attraction of unlike charges: proton-electron. Magnetic: Electron spin introduces magnetic forces. Electrons with opposite spins produce opposite magnetic poles. Opposite magnetic poles attract. Opposite spin is required for electrons to occupy the same orbital.

6. The Energies involved: Electron (orbital) Potential Energy: 2s 2p 3s 3p 3d 4s 4p 1s ENERGY LEVEL

7. 120 o 109.5 o 90 o 180 o Bond Angles

8. PxPx PyPy PzPz PxPx PyPy PzPz

9. Methane building blocks

10. 2s2p x 2p z 2p y 1s sp 3 sp 3 109.5 o Promote Hybridize x z y Methane: Carbon

11. CH 2 O 120 o

12. 2s2p x 2p z 2p y 1s sp 2 sp 2 sp 2 120 o Hybridized Formaldehyde: Carbon Promoted 120 o Trigonal Planar 2s + 2p x + 2p z

13. 2s2p x 2p z 2p y 1s sp 2 sp 2 sp 2 120 o Hybridized Formaldehyde: Oxygen 120 o Trigonal Planar Lone Pairs 2s + 2p x + 2p z

14. Formaldehyde Sigma bond 2 Lone Pairs bond bond

16. 2s2p x 2p z 2p y 1s sp Promoted Hybridized Hydrogen Cyanide: Carbon 2s + 2p x Linear

17. 2s2p x 2p z 2p y 1s sp Hybridized Hydrogen Cyanide: Nitrogen 2s + 2p x Linear

18. bond bond

19. PCl 5

20. 3s3p x 3p z 3p y 2 Neon 120 o Hybridized Phosphorus Pentachloride: Phosphorus Trigonal Bipyrimidal sp 3 d sp 3 d sp 3 d sp 3 d sp 3 d d xz d yz d xy d x 2 -y 2 d z 2 120 o 90 o Promoted