1. Valence Bond & hybridization
Google-youtube referrences:
1. Tro pages 408 and 411
2. Valence bond: molecular shape and
Orbital hybridization.
3. Section 7 5 sigma and pi bonds.
4. Sp3 Atomic orbital Hybridization – Chemistry Sigma and Pi bond symmetry

2. Valence Bond & hybridization
The orbital pattern valence electrons for 6C are: __ __ __ __ 2s 2px 2py 2pz The 4 bonds in CH4 are identical. The explanation is that valence electrons hybridize into an sp3 hybrid: __ __ __ __ sp3

3. Valence Bond;hybridization;polarity
B+LP = # bonds (single, double or triple) + # lone pair electrons
Comp.
B+LP
Normal
valence orbitals
Hybridized
orbitals
BeF2 2
__ __ __ __
2s p
__ __ __ __ sp
BF3 3
__ __ __ __
2s p
__ __ __ __
sp2
CH4 4
2s p
sp3
H2O
PF5 5
__ __ __ __ __ __ __
3s p __ __ 3d
__ __ __ __ __ __ __
sp3d __ __
BrF5 6
4s p __ __ 4d
sp3d __ __

4. Valence Bond;hybridization;polarity
B+LP = # Bonds (single, double, and triple) + # Lone pairs. 2 3 4 5 6

5. Valence Bond;hybridization;polarity
2s 2px 2py 2p
SP3 hybridization
The bond angle for H2O is 105o. H2S bond angle is closer to normal p orbitals (90o).

6. Valence Bond & hybridization
Draw the line bond formula for CO2: Hybridized sp orbitals ( 2 bonds ) are around C; hybridized sp2 (1 bond and 2 lone pairs) orbitals are around each oxygen.

7. Valence Bond;hybridization;polarity
The hybridized orbital pattern valence electrons for each 6C in C2H4 (sp2 ) is: __ __ __ __ The sp2 hybrid forms σ bonds, and the p orbital forms a π bond. sp2 p
The yellow and green bonds in figures a and c are also σ bonds. The purple bonds in figures b and c are π bonds.

8. Valence Bond;hybridization;polarity
Draw the line bond formula
shown right.
Write the electron geometry,
molecular geometry, and orbital
hybridization for the following
atoms in the line bond formula:
C in CCO C in NCC C in HCH
Write the following bond angles:
4. NCC CCO CCC HCH CCH
8. Locate the sigma (σ) and pi (π) bond(s).

9. Valence Bond;hybridization;polarity
Dipoles are
represented as
vectors.
As vectors:
A + B + C = R
If The tip of C is
at the origin, R =0,
and the molecule
Is non-polar. If
R ≠ 0, the molecule is polar.

10. Valence Bond;hybridization;polarity
Identify the electronic and molecular geometries. Draw the molecular formulas. Identify the hybridized orbitals and locate the sigma and pi bonds (if any). Predict the polarity (polar or nonpolar)for the following molecules (not ions): The first non-hydrogen atom is central. 1. CO2 2. CH2O 3. CH4O 4. C2H2 5. NO2- 6. HCN 7. XeF4 8. C2H4O 9. CO NO BrF5 12. IF C6H6 ( See next slide.) 14. I3-

11. Valence Bond;hybridization;polarity
Benzene (C6H6) has resonance structures (Figure 1) and is often written as shown in Figure 2. Note the σ and π bonds in Figures 3 and 4.
Figure 1
π bonds σ bond(s)
Figure 2
Figure Figure 4