Outline for Today Monday, Nov. 19 Chapter 9: Theories of Bonding - - PowerPoint PPT Presentation

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Outline for Today Monday, Nov. 19 Chapter 9: Theories of Bonding Molecular Orbitals of P-Block Elements Chapter 9 Integrative Example Problems 1 Making Molecular Orbitals * (sigma-star) Antibonding orbital (sigma) Bonding

SLIDE 1

Outline for Today

Monday, Nov. 19

Chapter 9: Theories of Bonding
Molecular Orbitals of P-Block Elements
Chapter 9 Integrative Example Problems

SLIDE 2

Making Molecular Orbitals

σ (sigma) Bonding orbital σ* (sigma-star) Antibonding orbital

SLIDE 3

Putting Electrons in Orbitals H2

Stable Molecule!

Highest Occupied Molecular Orbital (HOMO) Lowest Unoccupied Molecular Orbital (LUMO)

SLIDE 4

Molecular Orbitals for Diatomics Made from the P-Block Elements

1. Starting Atomic Orbitals

Draw the right number of boxes (1 for each subshell) Put them in order of increasing energy. Label the atomic orbitals

2. Mix the atomic orbitals.

For Diatomics: A.O. mix if they are the same shape, l, and have the same angular momentum, ml

3. Draw and label boxes for

molecular orbitals. Remember conservation of orbitals! Bonding orbitals are lower in energy than anti-bonding orbitals http://www.chemeddl.org/resources/models360/ models.php?pubchem=14774

SLIDE 5

Molecular Orbital Practice Problems

Draw the molecular orbital diagram for:
Li2
O2
O22-

SLIDE 6

Molecular Orbital Practice Problems

Draw the molecular orbital diagram for:
Li2
O2
NO
What is the bond order for each molecule?
How many electrons are in π bonds in each molecule?
Is it Paramagnetic or Diamagnetic?

SLIDE 7

Molecular Orbital Diagram for O2

HOMO LUMO Paramagnetic! para (greek)= attached Unpaired electrons means it will stick to the magnetic!

SLIDE 8

MO for Diatomics Made from the P-Block Elements

SLIDE 9

Molecular Orbitals for Diatomics Made from the P-Block Elements

O2, F2, Ne2 B2, C2, N2

SLIDE 10

MO for Diatomics Made from the P-Block Elements

SLIDE 11

3D molecular Geometry

Based on VSEPR theory and hybrid orbital theory, predict

the 3D structure and hybridization of:

1. XeF4
2. ClF3
3. SF4
In one sentence explain WHY you placed the lone pairs

where you did.

https://chem.libretexts.org/Ancillary_Materials/Visualizations_and_Simulations/ PhET_Simulations/PhET%3A_Molecule_Shapes

SLIDE 12

Visualizing multiple π Bonds

Using at least TWO sketches, draw the π bonds of carbon

monoxide.

SLIDE 13

Visualizing multiple π bonds

http://www.chemeddl.org/resources/models360/models.php?pubchem=281

SLIDE 14

Visualizing π bonds

Sketch a picture of CO2 to illustrate where the π bonds

are in this molecule.

According to Hybrid Orbital Theory, why are the two π

bonds perpendicular to each other?

http://www.chemeddl.org/resources/models360/models.php?pubchem=280

SLIDE 15

Comparing π bonds of Hybrid Orbital Theory and Molecular Orbital Theory

Below are the two π bonds predicted by MO theory.

How are they similar and how are they different from those predicted by hybrid orbital theory?

SLIDE 16

What’s the most likely isomer structure?

What is the best lewis structure of N2O?
What is the best lewis structure for SCN-?

SLIDE 17

What’s the difference between isomer structures and resonance structures?

O- C C H H H

O C C- H H H

O C C H H H H

Identify the two ISOMERS and the two RESONANCE structures

SLIDE 18

Drawing Isomers and Resonance Structures

Complete the Lewis structure of the following neutral

molecule

Draw an isomer of CNOF3

F C N O F F

SLIDE 19

Draw the resonance structures of PO43-

What is the average bond order of the P-O bonds?
How many σ bonds are in each structure?
How many π bonds are in each structure?
How many unhybridized p orbitals remain on the central

atom?