Sections 9.1 – 9.3 Valence Bond Theory Hybrid Orbitals Sigma and Pi Bonding.

Slides:

Advertisements

Similar presentations

Molecular Geometry (p. 232 – 236)

Advertisements

Theories of Chemical Bonding

Chapter 9 Chemical Bonding Theories Valence Bond Theory: Uses Lewis Structures Bonds form using shared electrons between overlapping orbitals on adjacent.

THE “MAKEUP” LECTURE TOPICS Molecular Polarity (8.7) Introduction to Bonding Theories (9.1) Valence Bond Theory (9.2) December 1, 2009.

Chapter 9 Chemical Bonding Theories Valence Bond Theory: Uses Lewis Structures Bonds form using shared electrons between overlapping orbitals on adjacent.

Chapter 10 Chemical Bonding Theories Valence Bond Theory: Uses Lewis Structures Bonds form using shared electrons between overlapping orbitals on adjacent.

Molecular Orbital Theory Atomic orbitals mix together and make: – Bonding Orbitals Electrons in these orbitals help hold atoms near each other – Antibonding.

Chapter 9 Chemical Bonding Theories Valence Bond Theory: Uses Lewis Structures Bonds form using shared electrons between overlapping orbitals on adjacent.

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals Chapter 10 Copyright © The McGraw-Hill Companies, Inc. Permission required.

Chapter 101 Bonding and Molecular Structure Chapter 10.

Hybridization Section Introduction A hybrid results from combining 2 of the same type of object and it has characteristics of both Atomic orbitals.

Sections 9.1 – 9.3 Valence Bond Theory and Hybrid Orbitals Bill Vining SUNY Oneonta.

John E. McMurry Paul D. Adams University of Arkansas Atomic and Molecular Orbitals.

Chemistry 100 Chapter 9 Molecular Geometry and Bonding Theories.

Medical Chemistry (1) 1433 – 1434 H. Carbon Compounds.

Molecular Shape VSEPR Model. Molecular Shape Physical/Chemical PROPERTIES SHAPE of Molecule (VSEPR) Overlap of ORBITALS (Hybridization)

Theories of Bonding and Structure CHAPTER 10 Chemistry: The Molecular Nature of Matter, 6 th edition By Jesperson, Brady, & Hyslop.

Chapter 9 Chemical Bonding Theories

Chemistry 100 Chapter 9 Molecular Geometry and Bonding Theories.

LCAO-molecular orbitals oIn MO Theory, atomic orbitals on the constituent atoms are combined to form bonding, non-bonding and anti-bonding orbitals for.

Chemical Bonding Hybridization and Molecular Orbital Theory.

Hybridization of Atomic Orbitals Some Material Copyright PGCC CHM 101 Sinex Some Graphics from Nelson Chemistry 12 Textbook.

Hybridization A Blending of Orbitals Methane CH 4 CH 4 Sometimes called “natural gas, ” methane is used to heat homes. Sometimes called “natural gas,

1 Chapter 10 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chemical Bonding II: Molecular Geometry and Hybridization.

Ch. 9 Molecular Geometry & Bonding Theories Lewis structures tell us which atoms are bonded together, but we will now explore the geometric shapes of these.

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals Chapter 10 Copyright © The McGraw-Hill Companies, Inc. Permission required.

Chemical Bonding and Molecular Geometry

Bonding theory Two methods of approximation are used to describe bonding between atoms. Valence bond method Bonds are assumed to be formed by overlap of.

Hybridization Section Introduction A hybrid results from combining 2 of the same type of object and it has characteristics of both Atomic orbitals.

Two Bonding Theories Valence Bond Theory (localized electron model) –Electrons in a molecule still occupy orbitals of individual atoms. Molecular Orbital.

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals Chapter 9 Copyright © The McGraw-Hill Companies, Inc. Permission required.

Hybridization and Other Good Stuff. Introduction A hybrid results from combining two of the same type of objects, and it has characteristics of both Atomic.

Orbital Hybridisation & VSEPR Learning Goals Students will be able to predict the hybridization in a variety of compounds using Lewis Structures & energy.

Chapter 9 Chemical Bonding Theories

Bonding Theories Part 2: VSEPR Theory. Objectives Describe how VSEPR theory helps predict the shapes of molecules Describe how VSEPR theory helps predict.

Lecture 43 Molecular Shapes Ozgur Unal 1.  Using the formula or the lewis structure of the following molecule, can you determine its three-dimensional.

CHEMICAL BONDING: ORBITALS Chapter 9. LOCALIZED ELECTRON (LE) MODEL A review: views a molecule as a collection of atoms bound together by sharing electrons.

4.6 Quantum Mechanics and Bonding: Hybridization.

To be viewed with PowerPoint. Animation doesn’t work otherwise.

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals Chapter 9 Copyright © The McGraw-Hill Companies, Inc. Permission required.

Hybrid Orbitals © Evan P. Silberstein, 2010.

CHAPTER 8: ADVANCED THEORIES OF COVALENT BONDING

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals Chapter 10 Copyright © The McGraw-Hill Companies, Inc. Permission required.

Unit 2.3: Chemical Bonding

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals Chapter 10 Copyright © The McGraw-Hill Companies, Inc. Permission required.

Chapter 2: Structure and Properties of Organic Molecules

Chapter 9 Chemical Bonding Theories

Structure & Properties of Matter

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals Chapter 9 Copyright © The McGraw-Hill Companies, Inc. Permission required.

Molecular Geometry & Bonding Theories

Chemical Bonding and Molecular Structure (Ch. 10)

The Nature of the Chemical Covalent Bond

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals Chapter 9 Copyright © The McGraw-Hill Companies, Inc. Permission required.

Bonding Theories Part 2: VSEPR Theory.

Hybridization of Orbitals

Chemical Bonding: Valence Bond & Molecular Orbital Theories Chapter 10 Section 4 through 8 of Jespersen 6th ed) Dr. C. Yau Fall

Molecular Shapes Lewis structures physical properties VSEPR

Chapter 9 Chemical Bonding Theories

Qantum Mechanics and Bonding Hybridization

Chapter 1B Carbon Compounds and Chemical Bonds

Qantum Mechanics and Bonding Hybridization

Molecular Shapes.

9-7 Polar Bonds vs. Polar Molecules (Section 12.3)

Chemical Bonding - HL.

Covalent Bonding: Orbitals What role do orbitals play in bonding?

Hybridization College Chemistry.

Chapter 9 Chemical Bonding Theories

Presentation transcript:

Sections 9.1 – 9.3 Valence Bond Theory Hybrid Orbitals Sigma and Pi Bonding

Chemical Bonding Theories Valence Bond Theory: Uses Lewis Structures Bonds form using shared electrons between overlapping orbitals on adjacent atoms. Orbitals arrange around central atom to avoid each other. Two types of bonds: sigma and pi. Molecular Orbital Theory: Uses MO Diagrams Orbitals on atoms “mix” to make molecular orbtials, which go over 2 or more atoms. Two electrons can be in an orbital. Orbitals are either: bonding, antibonding, or nonbonding. Bonds are either: sigma or pi.

Orbitals on bonding atoms overlap directly between bonding atoms Sigma (s) Bonding Between s orbitals Between p orbitals Between s and p orbitals

Consider VSEPR Shapes and bonding: Sigma (s) Bonding

What’s wrong with this picture? Atoms bond by having their valence orbitals overlap

Orbitals don’t go in same directions as atomic orbitals. 2s 2p z 2p x 2p y Orbitals in CH 4 Orbitals on C Conclusion: Atomic orbitals change shape when they make molecules.

Hybrid Orbitals Atomic valence orbitals “combine and mix” to form new “Hybrid Orbitals” Hybrid orbitals go in the VSEPR electron geometry directions.

Types of Hybrid Orbitals

4 Pairs : sp 3 hybrid orbitals

sp 3 hybrid orbitals: energetics

sp 3 bonding examples

3 Pairs: sp 2 hybrid orbitals

sp 2 bonding example: BF 3

2 Pairs : sp hybrid orbitals

sp bonding example: BeF 2

More complex example:

Expanded Valence Cases: 5 structural pairs

Expanded Valence Cases: 6 structural pairs

Summary

Bond angles

sigma Bonding involves: -- hybrid orbitals -- H 1s orbitals -- terminal atom p orbitals pi bonding involves unhybridized p orbitals Sigma vs. Pi Bonding

sigma bond formation Orbitals overlap directly between two nuclei:

pi Bond Formation

Bonding in Ethene

Bonding in Acetylene

Advanced: Allene Each end carbon is a flat trigonal. Are they co-planar or perpendicular?

Bonding in Allene

Bonding in Benzene

Summary

Conformations vs. Isomers Isomers: Molecules with same formula but different structure Conformers: Different temporary shapes of the same molecule

Bond Rotations CAN happen around single bonds Cannot happen around double bonds

cis-trans Isomerization When two groups are on a “side” of a molecule. cis trans

Can these molecules have cis-trans isomers?