1. Molecular Geometry Lewis Structures VSEPR Theory

2. Lewis Structures Count up the total number of valence electrons
Draw single bonds between central atom and surrounding atoms
Place remaining electrons, in pairs around appropriate atoms
Start with outer atoms
Make sure all atoms that need octets have octets
Make double bonds if necessary
Draw resonance structures (if applicable)

4. Lewis Structures Examples

5. Lewis Structures Ex: H2O 1. # valence electrons
2. Draw single bond between atoms.
3. Place remaining electrons around appropriate atoms.

6. Lewis Structures Ex: PF3 1. # valence electrons
2. Draw single bond between atoms.
3. Place remaining electrons around appropriate atoms, starting with outer atoms.

7. Lewis Structures Ex: NH41+ 1. # valence electrons
2. Draw single bond between atoms.
3. Place remaining electrons around appropriate atoms, starting with outer atoms.

8. Lewis Structures Ex: NO21- 1. # valence electrons
2. Draw single bond between atoms.
3. Place remaining electrons around appropriate atoms, starting with outer atoms.

9. Lewis Structures
Check octets of each atom.

10. Lewis Structures
Nitrate can have two resonance structures because the valence electrons are free to move over the entire structure of the polyatomic.

11. Lewis Structures  Formal Charge
When lewis structures have resonance structures, then the most preferred resonance structure is the one with the lowest formal charge.
Take last example:

12. Lewis Structures  Formal Charge
Formal Charge = V – N – ½(B)
(valence electrons) – (nonbonding electrons) – ½ (bonding electrons)

13. Formal Charge Formal charges should be as low as possible.
Formal charges of every element that makes up the molecule should equal the overall charge of the molecule.

14. Formal Charge
Negative formal charges should be on the more electronegative atom (elements closest to fluorine).
Positive formal charges should be on the less electronegative atoms.

15. Valence Shell Electron Repulsion Theory (VSEPR)
Electron Groups
Bonding Groups
Lone Pairs
Electron Geometry
Molecular Geometry
Approximate Bond Angles 2
Linear
180° 3
Trigonal Planar
120° 1
Bent
<120° 4
Tetrahedral
109.5°
Trigonal Pyramidal
<109.5°

16. VSEPR Determine the lewis structure and molecular shape of: CO2
# Valence electrons:
Lewis Structure:
Electron Geometry:
Molecular Geometry:

17. VSEPR Determine the lewis structure and molecular shape of: BF3
# Valence electrons:
Lewis Structure:
Electron Geometry:
Molecular Geometry:

18. VSEPR Determine the lewis structure and molecular shape of: SO2
# Valence electrons:
Lewis Structure:
Electron Geometry:
Molecular Geometry:

19. VSEPR Determine the lewis structure and molecular shape of: CH4
# Valence electrons:
Lewis Structure:
Electron Geometry:
Molecular Geometry:

20. VSEPR Determine the lewis structure and molecular shape of: NH3
# Valence electrons:
Lewis Structure:
Electron Geometry:
Molecular Geometry:

21. VSEPR Determine the lewis structure and molecular shape of: H2O
# Valence electrons:
Lewis Structure:
Electron Geometry:
Molecular Geometry:

22. Valence Shell Electron Repulsion Theory (VSEPR)

24. Polar Bonds
Created when electrons are drawn more closely to one of the atoms in the bond
The bond is polarized
Electrons are pulled toward more electronegative atoms
Electronegative atoms: atoms that strongly attract bonding electrons
Most electronegative element: Fluorine

25. Polar Bonds
Symbolize polar bonds with δ
Can also symbolize by

26. Polar Bonds
Examples:

27. Polar Bonds
Examples:

28. Polar Bonds
Examples:

29. Hybridization
Hydridization occurs to allow the atoms of the molecule to spread further away from each other
S orbitals and P orbitals hybridize into sp, sp2, and sp3 orbitals
Anything above sp3 does not occur because there are only 3 p orbitals
Therefore, DO NOT write sp4 , ect.
Also, there is only one s orbital, therefore, DO NOT write s2p3, ect

30. Hybridization
Note: We only look at hybridization in terms of the central atom.

31. Hybridization – The Short Cut

32. sp3 Hybridization

33. sp2 Hybridization

34. sp Hybridization

35. Determine the Hybridization of each of the following

37. Electron Geometry Molecular Geometry (Shape) Hybridization
Lewis structure (shown)
Electron geometry (central atoms)
Molecular geom. (central atoms)
Hybridization of central atoms
Bond angles

38. Electron Geometry Molecular Geometry (Shape) Hybridization
Lewis structure (shown)
Electron geometry (central atoms)
Tetrahedral
Trigonal planar
Molecular geom. (central atoms)
Hybridization of central atoms
Bond angles 1 2 3 4

39. Electron Geometry Molecular Geometry (Shape) Hybridization
Lewis structure (shown)
Electron geometry (central atoms)
Molecular geom. (central atoms)
Trigonal pyramidal
Tetrahedral
Trigonal planar
Bent
Hybridization of central atoms
Bond angles 1 2 3 4

40. Electron Geometry Molecular Geometry (Shape) Hybridization
Lewis structure (shown)
Electron geometry (central atoms)
Molecular geom. (central atoms)
Hybridization of central atoms
sp3
sp2
Bond angles 1 2 3 4

41. Electron Geometry Molecular Geometry (Shape) Hybridization
Lewis structure (shown)
Electron geometry (central atoms)
Molecular geom. (central atoms)
Hybridization of central atoms
Bond angles
<109.5
109.5
~120 1 2 3 4