2. Hybridization A Blending of Orbitals

3. Methane CH 4 CH 4 Sometimes called “natural gas, ” methane is used to heat homes. Sometimes called “natural gas, ” methane is used to heat homes.

4. Shape of Methane Tetrahedral geometry Tetrahedral geometry 109.5 o angle between bonds 109.5 o angle between bonds

5. Carbon’s atomic orbitals 4 valence electrons 4 valence electrons Outermost orbitals: 2s, 2p x, 2p y, 2p z Outermost orbitals: 2s, 2p x, 2p y, 2p z

6. How can this happen?

7. 2 possibilities Maybe our quantum mechanical model of atomic orbitals is totally wrong. Maybe our quantum mechanical model of atomic orbitals is totally wrong.OR Maybe carbon is doing something else with its orbitals to form this compound. Maybe carbon is doing something else with its orbitals to form this compound.

8. Hybridization occurs A mathematical blending of orbitals A mathematical blending of orbitals Number of atomic orbitals blended = number of hybrid orbitals produced Number of atomic orbitals blended = number of hybrid orbitals produced Result: Identical orbitals Result: Identical orbitals –New shape –New orientation in space

9. sp 3 hybridization s + p x + P y + p z = 4 sp 3 orbitals s + p x + P y + p z = 4 sp 3 orbitals

10. Sp 3 hybridization on carbon 4 identical sp 3 orbitals 109.5 o between orbitals Tetrahedral orientation

11. Bonds form when orbitals overlap Sigma bonds: end to end overlap of orbitals Sigma bonds: end to end overlap of orbitals

12. What happens in ethene? C2H4C2H4C2H4C2H4 Properties Properties Double bond between carbons Double bond between carbons Trigonal planar geometry around C Trigonal planar geometry around C 120 o bond angles 120 o bond angles

13. Sp 2 hybridization occurs S + p x + p y = 3 sp 2 orbitals S + p x + p y = 3 sp 2 orbitals 1 unused p orbital left over 1 unused p orbital left over

14. Bonding in ethene Sigma bond: end to end overlap Sigma bond: end to end overlap Pi bond: side to side overlap Pi bond: side to side overlap

15. Putting ethene together Carbon-carbon double bond = 1 sigma bond and 1 Pi bond Carbon-carbon double bond = 1 sigma bond and 1 Pi bond 4 C-H sigma bonds 4 C-H sigma bonds Trigonal planar Trigonal planar geometry results geometry results

16. What happens in ethyne? C 2 H 2 C 2 H 2 Linear geometry Linear geometry What type of hybridization is involved? What type of hybridization is involved? What hybrid and atomic orbitals can it use? What hybrid and atomic orbitals can it use? What types and numbers of bonds are present in the molecule? What types and numbers of bonds are present in the molecule?