Chapter 1: Matter and Measurement

Chapter 1 Matter and Measurement Philip Dutton University of Windsor, Canada N9B 3P4 Prentice Hall © 2002 General Chemistry Principles and Modern Applications Petrucci • Harwood • Herring 8th Edition[.]

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Philip Dutton University of Windsor, Canada

General Chemistry

Principles and Modern Applications

Petrucci • Harwood • Herring

8th Edition

Chapter 12: Chemical Bonding II:

Additional Aspects

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General Chemistry: Chapter 12

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Contents

12-6 Delocalized Electrons: Bonding in the

Benzene Molecule

Focus on Photoelectron Spectroscopy

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12-1 What a Bonding Theory Should Do

• Bring atoms together from a distance.

– e- are attracted to both nuclei

– e- are repelled by each other

– Nuclei are repelled by each other

• Plot the total potential energy verses distance.

– -ve energies correspond to net attractive forces

– +ve energies correspond to net repulsive forces

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Potential Energy Diagram

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12-2 Introduction to the Valence-Bond

Method

• Atomic orbital overlap describes covalent bonding.

• Area of overlap of orbitals is in phase

• A localized model of bonding.

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Bonding in H2S

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Example 12-1

Sketch the orbitals:

Overlap the orbitals:

Describe the shape: Trigonal pyramidal

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12-3 Hybridization of Atomic Orbitals

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sp3 Hybridization

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sp Hybridization

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Bonding in Methane

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sp Hybridization in Nitrogen

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Bonding in Nitrogen

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sp Hybridization

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Orbitals in Boron

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sp Hybridization

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Orbitals in Beryllium

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sp d and sp d Hybridization

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Hybrid Orbitals and VSEPR

• Write a plausible Lewis structure.

• Use VSEPR to predict electron geometry.

• Select the appropriate hybridization.

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12-4 Multiple Covalent Bonds

• Ethylene has a double bond in its Lewis structure.

• VSEPR says trigonal planar at carbon.

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Ethylene

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Acetylene

• Acetylene, C2H2, has a triple bond.

• VSEPR says linear at carbon.

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12-5 Molecular Orbital Theory

• Atomic orbitals are isolated on atoms.

• Molecular orbitals span two or more atoms.

• LCAO

– Linear combination of atomic orbitals

Ψ1 = φ1 + φ2 Ψ2 = φ1 - φ2

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Combining Atomic Orbitals

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Molecular Orbitals of Hydrogen

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Basic Ideas Concerning MOs

• Number of MOs = Number of AOs.

• Bonding and antibonding MOs formed from AOs.

• e- fill the lowest energy MO first.

• Pauli exclusion principle is followed.

• Hund’s rule is followed

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Bond Order

• Stable species have more electrons in bonding orbitals than antibonding.

Bond Order = No e- in bonding MOs - No e- in antibonding MOs

2

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Molecular Orbitals of the Second Period

• First period use only 1s orbitals.

• Second period have 2s and 2p orbitals available.

• p orbital overlap:

– End-on overlap is best – sigma bond (σ)

– Side-on overlap is good – pi bond (π)

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Molecular Orbitals of the Second Period

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Combining p orbitals

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MO Diagrams of Heteronuclear Diatomics

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12-6 Delocalized Electrons

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Benzene

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Benzene

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Ozone

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Bonding in Metals

Band theory.

• Extension of MO theory.

N atoms give N orbitals that

are closely spaced in energy

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Band Theory

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Semiconductors

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Photovoltaic Cells

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Focus on Photoelectron Spectroscopy

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Chapter 12 Questions

1, 3, 8, 10, 16, 29, 33, 39, 45, 59, 68, 72, 76

Tiêu đề	Matter and Measurement
Tác giả	Petrucci, Harwood, Herring
Người hướng dẫn	Philip Dutton
Trường học	University of Windsor
Chuyên ngành	General Chemistry
Thể loại	textbook
Năm xuất bản	2002
Thành phố	Windsor

Định dạng
Số trang	47
Dung lượng	2,47 MB