1. Catalyst

2. Quantum FTW

3. Lecture 2.6 – Orbital Hybridization

4. Today’s Learning Targets
LT 2.7 – I can explain how the overlapping of orbitals with unpaired electrons leads to the creation of covalent bonds and hybrid orbitals. I can explain how sp, sp2, and sp3 orbitals are created and identify a compound as containing one of these types of hybridization.

5. Valence – Bond Theory
While the discussions we have had about bonding has been correct, how can we explain this using quantum mechanics?
Valence Bond Theory – Atoms bond when electron densities are concentrated between the two atoms nuclei. Bonding occurs when valence orbitals of each atom overlap.

7. Quick Write
Draw the Lewis structure for CF4. Predict the electron domain geometry and the molecular geometry of the compound.

8. Consider Carbon… Carbon’s valence electron configuration looks like:
Show on board that in order for electrons to bond they must be unpaired. Therefore, in order to achieve an octet, one of the electrons in the 2s orbital is promoted to the open 2p orbital.

9. Consider Carbon…
If these form bonds with fluorine as predicted, then 3 of the bonds would have a higher energy than the 4th bond in the s orbital.
The s and p orbitals “mix” in order to form new orbitals that have equal energy
They form sp3 orbitals that allow for bonding to occur

10. Consider Carbon…
We can then draw in the one vacant 2p orbital that has the one unpaired electron of fluorine. We can

11. Orbital Hybridization
Hybrid Orbitals – The orbitals of an atom can “mix” to form new shapes
These orbitals have a new energy level that is a mixture of the two old energy levels.

12. sp3 Hybrid Orbitals Occur when 3 p orbitals and 1 s orbital mix
The 4 sp3 orbitals then arrange themselves such that a tetrahedral shape is formed.

13. sp Hybrid Orbitals
Form when the central atom mixes 1 s and 1 p orbital to form 2 sp hybrid orbitals.
Arranged in a linear shape and able to form 2 new bonds
INSERT BeF2 PICTURE
Draw the energy levels of Be. Be promotes one of its electrons to the 2p orbital so that it can form bonds. This causes 1 p and 1 s orbital to mix to form 2 sp hybrid orbitals. They take on a linear shape and allow new bonds to form.

14. sp2 Hybrid Orbitals
Occur when 2 p and 1 s orbital mix to form new shapes
Hybrid orbitals arrange in a trigonal planar shape and 3 new bonds can form
Example of BF3. Boron takes one of its 2s electrons and promotes it to the 2p orbital. It is important to remember that there still is an
empty p orbital. This will be important for pi bonds to form.

15. Molecules with Lone Pairs
Central atoms often have lone pairs on them.
These electron pairs are put in their own hybrid orbitals.
Example: H2O
Example of H2O. 2 bonds and 2 sets of lone pairs. Leads to the creation of sp3 hybridization (each lone pair gets its own hybrid orbital).

16. Quick Way to Remember Number of Hybrid Orbitals
Number of Lone Pairs and/or Bonds for Central Atom
Hybridization 2 sp 3
sp2 4
sp3
Note – We cannot use this theory for expanded Octet molecules.

17. Class Example
Determine the orbital hybridization of the central atom for NH2 –

18. Table Talk
Determine the orbital hybridization for SO32–

19. dsp3 and d2sp3 Hybridization
For compounds with expanded Octets, d orbitals are hybridized.
Number of Lone Pairs and/or Bonds for Central Atom
Hybridization 5
dsp3 6
d2sp3

20. White Board Races

21. Question 1
What is the hybridization of the carbon atom in CF4?

22. Question 2
What is the hybridization of the central atom in BI3?

23. Question 3
What is the hybridization of the central atom in H2O?

24. Question 4
What is the hybridization of the central atom in NH3?

25. Question 5
What is the hybridization of the central atom in CO32-?

26. Question 6
What is the hybridization of the central atom in SF6?

28. Closing Time Finish reading Chapter 9 and corresponding problems
Pre – Lab for Lab 3 due start of class Thursday/Friday
Lab questions for Labs 2 and 3 due next Wednesday