Chapter 9 The Shapes of Molecules Cocaine

Size: px
Start display at page:

Download "Chapter 9 The Shapes of Molecules Cocaine"

Transcription

1 Chapter 9 The Shapes of Molecules 1 Cocaine

2 10.1 Depicting Molecules & Ions with Lewis Structures 2

3 Number of Covalent Bonds 3 The number of covalent bonds can be determined from the number of electrons needed to complete an octet.

4 Molecules with Single Bonds 4 Ammonia, NH 3 1. Decide on the central atom; never H. Central atom is atom of lowest affinity for electrons. Therefore, N is central 2. Count total valence electrons H = 1 and N = 5 Total = (3 x 1) + 5 = 8 electrons / 4 pairs

5 Drawing Lewis Structure 5 3. Form a single bond between the central atom and each surrounding atom H N H H 4. Remaining electrons form LONE PAIRS to complete octet as needed. 3 BOND PAIRS and 1 LONE PAIR. Note that N has a share in 3 pairs (6 electrons), while H shares 1 pair.

6 Sulfite ion, SO Remaining pairs become lone pairs, first on outside atoms and then on central atom. Each atom is surrounded by an octet of electrons.

7 Molecules with Multiple Bonds Formaldehyde H 2 CO Step 4: Place lone pairs on outer atoms. 7 Step 5: To fulfill the octet on C, we form DOUBLE BONDS between C and O.

8 Double and even triple bonds are commonly observed for C, N, P, O, and S H 2 CO 8 SO 3 N 2 C 2 F 4 CO 2

9 RESONANCE: Delocalized Electron-Pair Bonding 9 These equivalent structures are called RESONANCE STRUCTURES. The true electronic structure is a HYBRID of the two.

10 Electron Delocalization 10 Lewis structures depict electrons as localized either on an individual atom (lone pairs) or in a bond between two atoms (shared pair). In a resonance hybrid, electrons are delocalized: their density is spread over a few adjacent atoms.

11 Fractional Bond Orders 11 Resonance hybrids often have fractional bond orders due to partial bonding. For O 3, bond order = 3 electron pairs 2 bonded-atom pairs = 1½

12 Nitrate ion, NO 3-12 Each atom is surrounded by an octet of electrons.

13 Formal Charge: Selecting the More Important Resonance Structure Formal charge is the charge an atom would have if all electrons were shared equally. Formal charge of atom = # of valence e - - (# of unshared valence e - + ½ # of shared valence e - ) 13 For O A in resonance form I, the formal charge is given by 6 valence e - - (4 unshared e - + ½(4 shared e - ) = = 0

14 Determine Formal Charge - Formal charges must sum to the actual charge on the species for all resonance forms. O A [6 4 ½(4)] = 0 O B [6 2 ½(6)] = +1 O C [6 6 ½(2)] = O A [6 6 ½(2)] = -1 O B [6 2 ½(6)] = +1 O C [6 4 ½(4)] = 0 For both these resonance forms the formal charges sum to zero, since O 3 is a neutral molecule. - Smaller formal charges (positive or negative) are preferable to larger ones. - The same nonzero formal charges on adjacent atoms are not preferred. Avoid like charges on adjacent atoms. - A more negative formal charge should reside on a more electronegative atom.

15 Choosing the More Important Resonance Form Example: NCO has 3 possible resonance forms: Resonance forms with smaller formal charges are preferred. Resonance form I is therefore not an important contributor. A negative formal charge should be placed on a more electronegative atoms. Resonance form III is preferred to resonance form II. The overall structure of the NCO - ion is still an average of all three forms, but resonance form III contributes most to the average.

16 Formal Charge Versus Oxidation Number For a formal charge, bonding electrons are shared equally by the atoms. The formal charge of an atom may change between resonance forms. 16 Formal charges Oxidation numbers For an oxidation number, bonding electrons are transferred to the more electronegative atom. The oxidation number of an atom is the same in all resonance forms.

17 Exceptions to the Octet Rule 17 Molecules with Electron-Deficient Atoms B and Be are commonly electron-deficient. Odd-Electron Species A molecule with an odd number of electrons is called a free radical.

18 Exceptions to the Octet Rule 18 Expanded Valence Shells An expanded valence shell is only possible for nonmetals from Period 3 or higher because these elements have available d orbitals.

19 10.2 The VSEPR Model 19 Valence Shell Electron Pair Repulsion theory. Most important factor in determining geometry is relative repulsion between electron pairs. In general, the relative repulsion strength are in the order: LP-LP > LP-BP > BP-BP Molecule adopts the shape that minimizes the electron pair repulsions.

20 Electron Group Arrangements & Molecular Shapes 20

21 Molecular shape with TWO Electron Groups (Linear Arrangement) Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 21 AX 2 Examples: CS 2, HCN, BeF 2 This key refers to Figures 10.3 through Figure 10.3

22 Molecular Shapes with THREE Electron Groups (Trigonal Planar Arrangement) Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 22 AX 3 Examples: SO 2, O 3, PbCl 2, SnBr 2 AX 2 E Examples: SO 3, BF 3, NO 3, CO 3 2 Figure 10.4

23 Factors Affecting Bond Angles 23 Nonbonding (Lone) Pairs A lone pair repels bonding pairs more strongly than bonding pairs repel each other. This decreases the angle between the bonding pairs. Double Bonds A double bond has greater electron density than a single bond, and repels the single bond electrons more than they repel each other.

24 Molecular Shapes with FOUR Electron Groups (Tetrahedral Arrangement) Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24 AX 4 Examples: CH 4, SiCl 4, SO 4 2, ClO 4 AX 3 E Examples: NH 3, PF 3 ClO 3, H 3 O + AX 2 E 2 Examples: H 2 O, OF 2, SCl 2 Figure 10.5

25 Lewis structures do not indicate molecular shape. 25 twist to the right twist to the left Figure 10.6

26 Molecular Shapes with FIVE Electron Groups (Trigonal Bipyramidal Arrangement) Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. AX 5 Examples: PF 5, AsF 5, SOF 4 AX 4 E Examples: SF 4, XeO 2 F 2 IF 4+, IO 2 F 2 26 AX 3 E 2 Examples: ClF 3, BrF 3 AX 2 E 3 Examples: XeF 2, I 3, IF 2 Figure 10.7

27 Axial and Equatorial Positions 27 A five electron-group system has two different positions for electron groups, and two ideal bond angles. Equatorial-equatorial repulsions are weaker than axial-equatorial repulsions. Where possible, lone pairs in a five electron-group system occupy equatorial positions.

28 Molecular Shapes with SIX Electron Groups (Octahedral Arrangement) 28 AX 6 Examples: SF 6, IOF 5 AX 5 E AX 4 E 2 Examples: BrF 5, TeF 5, XeOF 4 Examples: XeF 4, ICl 4 Figure 10.8

29 Molecular shapes for central atoms in Period 2 and in higher periods 29 Figure 10.9

30 The four steps in converting a molecular formula to a molecular shape 30 Molecular Formula Step 1 Draw Lewis structure. Lewis structure Step 2 Count all e - groups around central atom (A). Electrongroup arrangement Step 3 Bond angles Note positions of any lone pairs and double bonds. Step 4 Count bonding and nonbonding e - groups separately. Figure Molecular shape (AX m E n )

31 31 Structure Determination by VSEPR Ammonia, NH 3 1. Draw electron dot structure 2. Count BP s and LP s = 4 3. The 4 electron pairs are at the corners of a tetrahedron. H N H lone pair of electrons in tetrahedral position H

32 Structure Determination by VSEPR Formaldehyde, H 2 CO 1. Draw electron dot structure 2. Count BP s and LP s at C H O 3. There are 3 electron lumps around C at the corners of a planar triangle. C H 32 O C The electron pair geometry is TRIGONAL PLANAR with 120 o bond angles. H H The molecular geometry is also trigonal planar.

33 Molecular Shapes with More than One Central Atom Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 33 ethane CH 3 CH 3 ethanol CH 3 CH 2 OH Figure 10.12

34 Molecular Shapes with More than One Central Atom 34 Methanol, CH 3 OH Determine H-C-H and C-O-H bond angles H-C-H = 109 o C-O-H = 109 o In both cases the atom is surrounded by 4 electron groups. H H C O H H

35 Molecular Shapes with More than One Central Atom 35 Acetonitrile, CH 3 CN Determine bond angles H H C C N H-C-H = 109 o C-C-N = 180 o 109 H 180 One C is surrounded by 4 electron groups and the other C by 2 electron groups

36 10.3 Molecular Shape 36 & Molecular Polarity Overall molecular polarity depends on both shape and bond polarity. The polarity of a molecule is measured by its dipole moment (μ), which is given in the unit debye (D). A molecule is polar if - it contains one or more polar bonds and - the individual bond dipoles do not cancel.

37 The orientation of polar molecules in an electric field. 37 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Molecules are randomly oriented. Figure Molecules become oriented when the field is turned on.

38 Bond Polarity, Bond Angle, and Dipole Moment 38 Compare CO 2 and H 2 O. Which one is polar?

39 Bond Polarity, Bond Angle, and Dipole Moment Molecules with the same shape may have different polarities. CH 4 CCl 4 Polar or Not? 39 Only CH 4 and CCl 4 are NOT polar. They are the two molecules that are symmetrical.

40 40 Polar or Nonpolar? Consider AB 3 molecules: BF 3, Cl 2 CO, and NH 3.

41 Effect of Molecular Polarity on Behavior 41 Example: cis and trans isomers of 1,2-dichloroethylene, C 2 H 2 Cl 2 The cis isomer is polar while the trans isomer is not. The boiling point of the cis isomer boils is 13 C higher than that of the trans isomer.

10-1. The Shapes of Molecules, chapter 10

10-1. The Shapes of Molecules, chapter 10 10-1 The Shapes of Molecules, chapter 10 The Shapes of Molecules; Goals 10.1 Depicting Molecules and Ions with Lewis Structures 10.2 Valence-Shell Electron-Pair Repulsion (VSEPR) Theory 10.3 Molecular

More information

Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 10. The Shapes of Molecules 10-1

Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 10. The Shapes of Molecules 10-1 Chapter 10 The Shapes of Molecules 10-1 The Shapes of Molecules 10.1 Depicting Molecules and Ions with Lewis Structures 10.2 Valence-Shell Electron-Pair Repulsion (VSEPR) Theory and Molecular Shape 10.3

More information

Lewis structures show the number and type of bonds between atoms in a molecule or polyatomic ion.

Lewis structures show the number and type of bonds between atoms in a molecule or polyatomic ion. VSEPR & Geometry Lewis structures show the number and type of bonds between atoms in a molecule or polyatomic ion. Lewis structures are not intended to show the 3-dimensional structure (i.e. shape or geometry)

More information

The Shapes of Molecules. Chemistry II

The Shapes of Molecules. Chemistry II The Shapes of Molecules Chemistry II Lewis Structures DEFINITIN: A structure of a molecule showing how the valence electrons are arranged. 1) nly the valence electrons appear in a Lewis structure. 2) The

More information

Chapter 9 Molecular Geometry. Lewis Theory-VSEPR Valence Bond Theory Molecular Orbital Theory

Chapter 9 Molecular Geometry. Lewis Theory-VSEPR Valence Bond Theory Molecular Orbital Theory Chapter 9 Molecular Geometry Lewis Theory-VSEPR Valence Bond Theory Molecular Orbital Theory Sulfanilamide Lewis Structures and the Real 3D-Shape of Molecules Lewis Theory of Molecular Shape and Polarity

More information

Chapter 10. The Shapes of Molecules

Chapter 10. The Shapes of Molecules Chapter 10 The Shapes of Molecules Molecules are visualized using Lewis Structures Molecular formula Step 1 Atom placement Step 2 Add A-group numbers ctet Rule Sum of valence e - Step 3 Remaining valence

More information

Chapter 7. Chemical Bonding I: Basic Concepts

Chapter 7. Chemical Bonding I: Basic Concepts Chapter 7. Chemical Bonding I: Basic Concepts Chemical bond: is an attractive force that holds 2 atoms together and forms as a result of interactions between electrons found in combining atoms We rarely

More information

Chapter 10 Theories of Covalent Bonding

Chapter 10 Theories of Covalent Bonding Chapter 10 Theories of Covalent Bonding 1 Atomic Orbitals Molecules Bonding and 2 Molecular Structure Questions How are molecules held together? Why is O 2 paramagnetic? And how is this property connected

More information

Chapter 9. Chemical Bonding II: Molecular Geometry and Bonding Theories

Chapter 9. Chemical Bonding II: Molecular Geometry and Bonding Theories Chapter 9 Chemical Bonding II: Molecular Geometry and Bonding Theories Topics Molecular Geometry Molecular Geometry and Polarity Valence Bond Theory Hybridization of Atomic Orbitals Hybridization in Molecules

More information

CHEMISTRY 112 LECTURE EXAM II Material

CHEMISTRY 112 LECTURE EXAM II Material CHEMISTRY 112 LECTURE EXAM II Material Part I Chemical Bonding I Lewis Theory Chapter 9 pages 376-386 A. Drawing electron dot structures HOW TO: 1. Write e- dot structure for the individual atoms. 2. a)

More information

Chemical Bonding AP Chemistry Ms. Grobsky

Chemical Bonding AP Chemistry Ms. Grobsky Chemical Bonding AP Chemistry Ms. Grobsky What Determines the Type of Bonding in Any Substance? Why do Atoms Bond? The key to answering the first question are found in the electronic structure of the atoms

More information

Subtopic 4.2 MOLECULAR SHAPE AND POLARITY

Subtopic 4.2 MOLECULAR SHAPE AND POLARITY Subtopic 4.2 MOLECULAR SHAPE AND POLARITY 1 LEARNING OUTCOMES (covalent bonding) 1. Draw the Lewis structure of covalent molecules (octet rule such as NH 3, CCl 4, H 2 O, CO 2, N 2 O 4, and exception to

More information

Bonding and Molecular Structure - PART 1 - VSEPR

Bonding and Molecular Structure - PART 1 - VSEPR Bonding and Molecular Structure - PART 1 - VSEPR Objectives: 1. Understand and become proficient at using VSEPR to predict the geometries of simple molecules and ions. 2. Become proficient at predicting

More information

Chapter 10 Molecular Geometry and Chemical Bonding Theory. Copyright Cengage Learning. All rights reserved. 10 1

Chapter 10 Molecular Geometry and Chemical Bonding Theory. Copyright Cengage Learning. All rights reserved. 10 1 Chapter 10 Molecular Geometry and Chemical Bonding Theory Copyright Cengage Learning. All rights reserved. 10 1 Molecular geometry is the general shape of a molecule, as determined by the relative positions

More information

EXAM II Material. Part I Chemical Bonding I Lewis Theory Chapter 9 pages A. Drawing electron dot structures HOW TO:

EXAM II Material. Part I Chemical Bonding I Lewis Theory Chapter 9 pages A. Drawing electron dot structures HOW TO: CHEMISTRY 112 LECTURE EXAM II Material Part I Chemical Bonding I Lewis Theory Chapter 9 pages 376-386 A. Drawing electron dot structures HOW TO: 1. Write e- dot structure for the individual atoms. 2. a)

More information

Molecular shape is determined by the number of bonds that form around individual atoms.

Molecular shape is determined by the number of bonds that form around individual atoms. Chapter 9 CH 180 Major Concepts: Molecular shape is determined by the number of bonds that form around individual atoms. Sublevels (s, p, d, & f) of separate atoms may overlap and result in hybrid orbitals

More information

Name Unit Three MC Practice March 15, 2017

Name Unit Three MC Practice March 15, 2017 Unit Three: Bonding & Molecular Geometry Name Unit Three MC Practice March 15, 2017 1. What is the hybridization of the oxygen atom in water? a) sp b) sp 2 c) sp 3 d) It is not hybridized 2. When a double

More information

Adapted from CHM 130 Maricopa County, AZ Molecular Geometry and Lewis Dot Formulas Introduction

Adapted from CHM 130 Maricopa County, AZ Molecular Geometry and Lewis Dot Formulas Introduction Adapted from CHM 130 Maricopa County, AZ Molecular Geometry and Lewis Dot Formulas Introduction A chemical bond is an intramolecular (within the molecule) force holding two or more atoms together. Covalent

More information

General and Inorganic Chemistry I.

General and Inorganic Chemistry I. General and Inorganic Chemistry I. Lecture 1 István Szalai Eötvös University István Szalai (Eötvös University) Lecture 1 1 / 29 Outline István Szalai (Eötvös University) Lecture 1 2 / 29 Lewis Formulas

More information

Chapter 9 Molecular Geometries. and Bonding Theories

Chapter 9 Molecular Geometries. and Bonding Theories Chapter 9 Molecular Geometries and Bonding Theories Coverage of Chapter 9 9.1 All 9.2 All 9.3 All 9.4 All 9.5 Omit Hybridization Involving d Orbitals 9.6 All 9.7 and 9.8 Omit ALL MOLECULAR SHAPES The shape

More information

Lecture outline: Section 9. theory 2. Valence bond theory 3. Molecular orbital theory. S. Ensign, Chem. 1210

Lecture outline: Section 9. theory 2. Valence bond theory 3. Molecular orbital theory. S. Ensign, Chem. 1210 Lecture outline: Section 9 Molecular l geometry and bonding theories 1. Valence shell electron pair repulsion theory 2. Valence bond theory 3. Molecular orbital theory 1 Ionic bonding Covalent bonding

More information

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals Chapter 1

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals Chapter 1 Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals Chapter 1 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. How to get the book of

More information

Molecular Geometry. Objectives N H H. The objectives of this laboratory are to:

Molecular Geometry. Objectives N H H. The objectives of this laboratory are to: Objectives The objectives of this laboratory are to: Molecular Geometry Write Lewis structure representations of the bonding and valence electrons in molecules. Use the VSEPR model to predict the molecular

More information

CHEMISTRY. Chapter 10 Theories of Bonding and Structure. The Molecular Nature of Matter. Jespersen Brady Hyslop SIXTH EDITION

CHEMISTRY. Chapter 10 Theories of Bonding and Structure. The Molecular Nature of Matter. Jespersen Brady Hyslop SIXTH EDITION CHEMISTRY The Molecular Nature of Matter SIXTH EDITION Jespersen Brady Hyslop Chapter 10 Theories of Bonding and Structure Copyright 2012 by John Wiley & Sons, Inc. Molecular Structures Molecules containing

More information

Chapter 10. Geometry

Chapter 10. Geometry Chapter 10 Molec cular Geometry 1 CHAPTER OUTLINE Molecular Geometry Molecular Polarity VSEPR Model Summary of Molecular Shapes Hybridization Molecular Orbital Theory Bond Angles 2 MOLECULAR GEOMETRY Molecular

More information

Molecular Geometry and Chemical Bonding Theory

Molecular Geometry and Chemical Bonding Theory Molecular Geometry and Chemical Bonding Theory The Valence -Shell Electron -Pair Repulsion (VSEPR) Model predicts the shapes of the molecules and ions by assuming that the valence shell electron pairs

More information

N = 727 Mean = 68% Diff T-Test P-Value SI 223 (31%) 71% No SI 504 (69%) 66% Test 2 - Letter Grade Distribution by SI Attendance

N = 727 Mean = 68% Diff T-Test P-Value SI 223 (31%) 71% No SI 504 (69%) 66% Test 2 - Letter Grade Distribution by SI Attendance CHEM 200/202 Exam 2 N = 727 Mean = 68% Diff T-Test P-Value SI 223 (31%) 71% No SI 504 (69%) 66% 5%

More information

EXPERIMENT #13 Lewis Structures and Molecular Geometry

EXPERIMENT #13 Lewis Structures and Molecular Geometry OBJECTIVES: EXPERIMENT #13 s and Draw Lewis structures of atoms, ions, and molecules Build models of linear, trigonal planar tetrahedral, trigonal bipyramidal, and octahedral arrangements of electron pairs

More information

VSEPR. Valence Shell Electron Pair Repulsion Theory

VSEPR. Valence Shell Electron Pair Repulsion Theory VSEPR Valence Shell Electron Pair Repulsion Theory Vocabulary: domain = any electron pair or bond (single, double or triple) is considered one domain. bonding pair = shared pair = any electron pair that

More information

Lecture 17 - Covalent Bonding. Lecture 17 - VSEPR and Molecular Shape. Lecture 17 - Introduction. Lecture 17 - VSEPR and Molecular Shape

Lecture 17 - Covalent Bonding. Lecture 17 - VSEPR and Molecular Shape. Lecture 17 - Introduction. Lecture 17 - VSEPR and Molecular Shape Chem 103, Section F0F Unit VI - Compounds Part II: Covalent Compounds Lecture 17 Using the Valence-Shell Electron-Pair Repulsion (VSEPR) Theory to predict molecular shapes Molecular shape and polarity

More information

Chapter 7 Chemical Bonding and Molecular Structure

Chapter 7 Chemical Bonding and Molecular Structure Chapter 7 Chemical Bonding and Molecular Structure Three Types of Chemical Bonding (1) Ionic: formed by electron transfer (2) Covalent: formed by electron sharing (3) Metallic: attraction between metal

More information

Chapter 9 Molecular Geometry and Bonding Theories

Chapter 9 Molecular Geometry and Bonding Theories Chapter 9 Molecular Geometry and Bonding Theories molecular shapes the VSEPR model molecular shape and molecular polarity covalent bonding and orbital overlap hybrid orbitals multiple bonds 9.1 Molecular

More information

Molecular Geometry. Valence Shell Electron Pair. What Determines the Shape of a Molecule? Repulsion Theory (VSEPR) Localized Electron Model

Molecular Geometry. Valence Shell Electron Pair. What Determines the Shape of a Molecule? Repulsion Theory (VSEPR) Localized Electron Model Molecular Geometry Learn Shapes you will Because the physical and chemical properties of compounds are tied to their structures, the importance of molecular geometry can not be overstated. Localized Electron

More information

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals 1 Chemical Bonding II Molecular Geometry (10.1) Dipole Moments (10.2) Valence Bond Theory (10.3) Hybridization of Atomic Orbitals

More information

Announcements. Chapter 10 The Shapes of Molecules. Chem 7 Final Exam Wednesday, Oct 10 1:30-3:30AM Chapter or 75 multiple choice questions

Announcements. Chapter 10 The Shapes of Molecules. Chem 7 Final Exam Wednesday, Oct 10 1:30-3:30AM Chapter or 75 multiple choice questions Exam III (Chapter 7-10) Wednesday, October 3, 2012 Time: 6:00PM - 7:30PM SEC A 214A and 215A Announcements Chem 7 inal Exam Wednesday, Oct 10 1:30-3:30AM Chapter 1-12 70 or 75 multiple choice questions

More information

Practice Worksheet for Lewis Structures (Mahaffy Ch )

Practice Worksheet for Lewis Structures (Mahaffy Ch ) Practice Worksheet for Lewis Structures (Mahaffy Ch. 10.1 10.5 ) 1. Main concepts Lewis Structures a. Connectivity b. Bonds & Lone pairs c. Electron Geometry & Molecular Shape d. Resonance Structures Formal

More information

Chapters 8 and 9. Octet Rule Breakers Shapes

Chapters 8 and 9. Octet Rule Breakers Shapes Chapters 8 and 9 Octet Rule Breakers Shapes Bond Energies Bond Energy (review): The energy needed to break one mole of covalent bonds in the gas phase Breaking bonds consumes energy; forming bonds releases

More information

Structures, Shapes and Polarity. of Molecules. Level 2 recap: - Polar and non polar bonds - Lewis diagrams - Lone pairs - Shapes - Polarity

Structures, Shapes and Polarity. of Molecules. Level 2 recap: - Polar and non polar bonds - Lewis diagrams - Lone pairs - Shapes - Polarity Structures, Shapes and Polarity Level 2 recap: - Polar and non polar bonds - Lewis diagrams - Lone pairs - Shapes - Polarity of Molecules Do now: Brainstorm what you know/remember about these L2 concepts

More information

Chapter 4 Lecture Outline. Copyright McGraw-Hill Education. Permission required for reproduction or display.

Chapter 4 Lecture Outline. Copyright McGraw-Hill Education. Permission required for reproduction or display. Chapter 4 Lecture Outline 1 Copyright McGraw-ill Education. Permission required for reproduction or display. 4.1 Introduction to Covalent Bonding Covalent bonds result from the sharing of electrons between

More information

Introduction to VSEPR Theory 1

Introduction to VSEPR Theory 1 1 Class 8: Introduction to VSEPR Theory Sec 10.2 VSEPR Theory: The Five Basic Shapes Two Electron Groups: Linear Geometry Three Electron Groups: Trigonal Planar Geometry Four Electron Groups: Tetrahedral

More information

Chapter 9. Molecular Geometry and Bonding Theories

Chapter 9. Molecular Geometry and Bonding Theories 9.1 Molecular Shapes Read Sec. 9.1 and 9.2, then complete the Sample and Practice Exercises in these sections. Sample Exercise 9.1 (p. 347) Use the VSEPR model to predict the molecular geometries of a)

More information

Experiment 21 Lewis structures and VSEPR Theory

Experiment 21 Lewis structures and VSEPR Theory Experiment 21 Lewis structures and VSEPR Theory Introduction 1. Lewis Structures and Formal Charge LG.N. Lewis, at the University of California at Berkeley devised a simple way to understand the nature

More information

Molecular Geometry & Polarity

Molecular Geometry & Polarity Molecular Geometry & Polarity Learn Shapes you will Because the physical and chemical properties of compounds are tied to their structures, the importance of molecular geometry can not be overstated. Localized

More information

COVALENT BONDING CHEMICAL BONDING I: LEWIS MODEL. Chapter 7

COVALENT BONDING CHEMICAL BONDING I: LEWIS MODEL. Chapter 7 Chapter 7 P a g e 1 COVALENT BONDING Covalent Bonds Covalent bonds occur between two or more nonmetals. The two atoms share electrons between them, composing a molecule. Covalently bonded compounds are

More information

CHEMICAL BONDING. Chemical Bonds. Ionic Bonding. Lewis Symbols

CHEMICAL BONDING. Chemical Bonds. Ionic Bonding. Lewis Symbols CHEMICAL BONDING Chemical Bonds Lewis Symbols Octet Rule whenever possible, valence electrons in covalent compounds distribute so that each main-group element is surrounded by 8 electrons (except hydrogen

More information

2011, Robert Ayton. All rights reserved.

2011, Robert Ayton. All rights reserved. Chemical Bonding Outline 1. Lewis Dot Structures 2. Bonds 3. Formal Charges 4. VSEPR (Molecular Geometry and Hybridzation) 5. Common Resonance Structures and Dimerization Review 1. Lewis Dot Structures

More information

Chapter 9 Molecular Geometry Valence Bond and Molecular Orbital Theory

Chapter 9 Molecular Geometry Valence Bond and Molecular Orbital Theory Chapter 9 Molecular Geometry Valence Bond and Molecular Orbital Theory Chapter Objectives: Learn the basics of Valence Bond Theory and Molecular Orbital Theory and how they are used to model covalent bonding.

More information

Lewis Structure. Lewis Structures & VSEPR. Octet & Duet Rules. Steps for drawing Lewis Structures

Lewis Structure. Lewis Structures & VSEPR. Octet & Duet Rules. Steps for drawing Lewis Structures Lewis Structure Lewis Structures & VSEPR Lewis Structures shows how the are arranged among the atoms of a molecule There are rules for Lewis Structures that are based on the formation of a Atoms want to

More information

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals Chapter 10 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 Valence shell electron

More information

Ex. 1) F F bond in F = 0 < % covalent, no transfer of electrons

Ex. 1) F F bond in F = 0 < % covalent, no transfer of electrons #60 Notes Unit 8: Bonding Ch. Bonding I. Bond Character Bonds are usually combinations of ionic and covalent character. The electronegativity difference is used to determine a bond s character. Electronegativity

More information

Chemistry 1B Fall 2012 Lectures Chemistry 1B. Fall Lectures Classical theories of bonding and molecular geometry (ch 13)

Chemistry 1B Fall 2012 Lectures Chemistry 1B. Fall Lectures Classical theories of bonding and molecular geometry (ch 13) Chemistry 1B Fall 2012 1 Classical theories of bonding and molecular geometry (ch 13) Lewis electron-dot structures Bond energies and ΔH (back to pp. 606-610, much of this in Chem 1C) Valence State Electron-Pair

More information

Chemistry 1B Fall 2012

Chemistry 1B Fall 2012 Chemistry 1B Fall 2012 Lectures 10-11-12 1 Classical theories of bonding and molecular geometry (ch 13) Lewis electron-dot structures Bond energies and ΔH (back to pp. 606-610, much of this in Chem 1C)

More information

bond energy- energy required to break a chemical bond -We can measure bond energy to determine strength of interaction

bond energy- energy required to break a chemical bond -We can measure bond energy to determine strength of interaction bond energy- energy required to break a chemical bond -We can measure bond energy to determine strength of interaction ionic compound- a metal reacts with a nonmetal Ionic bonds form when an atom that

More information

Lewis Dot Structures for Methane, CH 4 The central C atom is bonded by single bonds (-) to 4 individual H atoms

Lewis Dot Structures for Methane, CH 4 The central C atom is bonded by single bonds (-) to 4 individual H atoms Chapter 10 (Hill/Petrucci/McCreary/Perry Bonding Theory and Molecular Structure This chapter deals with two additional approaches chemists use to describe chemical bonding: valence-shell electron pair

More information

Lewis Dot Formulas and Molecular Shapes

Lewis Dot Formulas and Molecular Shapes Lewis Dot Formulas and Molecular Shapes Introduction A chemical bond is an intramolecular (within the molecule) force holding two or more atoms together. Covalent chemical bonds are formed by valence electrons

More information

LESSON 10. Glossary: Molecular Geometry. a quantitative measure of the degree of charge separation in a molecule. Dipole moment

LESSON 10. Glossary: Molecular Geometry. a quantitative measure of the degree of charge separation in a molecule. Dipole moment LESSON 10 Glossary: Molecular Geometry Dipole moment Electronegativity Molecular geometry Pi bond Polar covalent bond Sigma bond Valence-shell electronpair repulsion (VSEPR) model a quantitative measure

More information

Molecular Geometry and Bonding Theories. Molecular Shapes. Molecular Shapes. Chapter 9 Part 2 November 16 th, 2004

Molecular Geometry and Bonding Theories. Molecular Shapes. Molecular Shapes. Chapter 9 Part 2 November 16 th, 2004 Molecular Geometry and Bonding Theories Chapter 9 Part 2 November 16 th, 2004 8 Molecular Shapes When considering the geometry about the central atom, we consider all electrons (lone pairs and bonding

More information

Problems and questions How is a molecule or polyatomic ion held together? Why are atoms distributed at strange angles? Why are molecules not flat?

Problems and questions How is a molecule or polyatomic ion held together? Why are atoms distributed at strange angles? Why are molecules not flat? 1 Cocaine 2 Problems and questions ow is a molecule or polyatomic ion held together? Why are atoms distributed at strange angles? Why are molecules not flat? Can we predict the structure? ow is structure

More information

Chemical Bonding and Molecular Models

Chemical Bonding and Molecular Models 25 Chemical Bonding and Molecular Models A chemical bond is a force that holds groups of two or more atoms together and makes them function as a unit. Bonding involves only the valence (outer shell) electrons

More information

PART 3 Chemical Bonds, Valence Bond Method, and Molecular Shapes. Reference: Chapter 9 10 in textbook

PART 3 Chemical Bonds, Valence Bond Method, and Molecular Shapes. Reference: Chapter 9 10 in textbook PART 3 Chemical Bonds, Valence Bond Method, and Molecular Shapes Reference: Chapter 9 10 in textbook 1 Valence Electrons Valence ae Electron Define: the outer shell electrons Important for determination

More information

Molecular Structure and Orbitals

Molecular Structure and Orbitals CHEM 1411 General Chemistry Chemistry: An Atoms First Approach by Zumdahl 2 5 Molecular Structure and Orbitals Chapter Objectives: Learn the basics of Valence Bond Theory and Molecular Orbital Theory and

More information

8.1 Types of Chemical Bonds List and define three types of bonding. chapter 8 Bonding General Concepts.notebook. September 10, 2015

8.1 Types of Chemical Bonds List and define three types of bonding. chapter 8 Bonding General Concepts.notebook. September 10, 2015 chapter 8 Bonding General Concepts.notebook Chapter 8: Bonding: General Concepts Mar 13 11:15 AM 8.1 Types of Chemical Bonds List and define three types of bonding. Bonds are forces that hold groups of

More information

5 Polyatomic molecules

5 Polyatomic molecules s manual for Burrows et.al. Chemistry 3 Third edition 5 Polyatomic molecules Answers to worked examples WE 5.1 Formal charges in N 2 (on p. 221 in Chemistry 3 ) Use formal charges to decide whether oxygen

More information

Shapes of Molecules and Hybridization

Shapes of Molecules and Hybridization Shapes of Molecules and Hybridization A. Molecular Geometry Lewis structures provide us with the number and types of bonds around a central atom, as well as any NB electron pairs. They do not tell us the

More information

Honors Chemistry Unit 6 ( )

Honors Chemistry Unit 6 ( ) Honors Chemistry Unit 6 (2017-2018) Lewis Dot Structures VSEPR Structures 1 We are learning to: 1. Represent compounds with Lewis structures. 2. Apply the VSEPR theory to determine the molecular geometry

More information

Lewis Structure and Electron Dot Models

Lewis Structure and Electron Dot Models Lewis Structure and Electron Dot Models The Lewis Structure is a method of displaying the electrons present in any given atom or compound. Steps: 1. Make a skeleton structure 2. Count all e- available

More information

Chapter 10 Chemical Bonding II: Molecular Shapes, Valence Bond Theory, and Molecular Orbital Theory

Chapter 10 Chemical Bonding II: Molecular Shapes, Valence Bond Theory, and Molecular Orbital Theory 10.1 Artificial Sweeteners: Fooled by Molecular Shape 425 10.2 VSEPR Theory: The Five Basic Shapes 426 10.3 VSEPR Theory: The Effect of Lone Pairs 430 10.4 VSEPR Theory: Predicting Molecular Geometries

More information

Chemical Bonding. Types of Bonds. Ionic Bonding. Resonance Structures. Molecular Geometries. VSEPR Basic Shapes 3-D Notation Hybridization (Lab)

Chemical Bonding. Types of Bonds. Ionic Bonding. Resonance Structures. Molecular Geometries. VSEPR Basic Shapes 3-D Notation Hybridization (Lab) Chemical Bonding Types of Bonds Ionic Bonding Lewis Structures Covalent Bonding Resonance Structures Octet Rule Polar Molecules Molecular Geometries VSEPR Basic Shapes 3-D Notation Hybridization (Lab)

More information

Chapter 10. VSEPR Model: Geometries

Chapter 10. VSEPR Model: Geometries Chapter 10 Molecular Geometry VSEPR Model: Geometries Valence Shell Electron Pair Repulsion Theory Electron pairs repel and get as far apart as possible Example: Water Four electron pairs Farthest apart

More information

Chemical Bonding I: Basic Concepts

Chemical Bonding I: Basic Concepts Chemical Bonding I: Basic Concepts Chapter 9 Chang & Goldsby Modified by Dr. Hahn Copyright McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent

More information

Chapter 6. The Chemical Bond

Chapter 6. The Chemical Bond Chapter 6 The Chemical Bond Some questions Why do noble gases rarely bond to other elements? How does this relate to why the atoms of other elements do form bonds? Why do certain elements combine to form

More information

CHEM 110 Exam 2 - Practice Test 1 - Solutions

CHEM 110 Exam 2 - Practice Test 1 - Solutions CHEM 110 Exam 2 - Practice Test 1 - Solutions 1D 1 has a triple bond. 2 has a double bond. 3 and 4 have single bonds. The stronger the bond, the shorter the length. 2A A 1:1 ratio means there must be the

More information

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals Chapter 10

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals Chapter 10 Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals Chapter 10 Linear Trigonal 180 o planar 120 o Tetrahedral 109.5 o Trigonal Bipyramidal 120 and 90 o Octahedral 90 o linear Linear

More information

Lectures Chemistry 1B Fall 2013 Lectures Chemistry 1B. Fall 2013

Lectures Chemistry 1B Fall 2013 Lectures Chemistry 1B. Fall 2013 Classical theories of bonding and molecular geometry (ch 13) Chemistry 1B Fall 2013 Lewis electron-dot structures Bond lengths, energies and ΔH (back to pp. 615-622, much of this in Chem 1C) Valence State

More information

Chapter 13: Phenomena

Chapter 13: Phenomena Chapter 13: Phenomena Phenomena: Scientists measured the bond angles of some common molecules. In the pictures below each line represents a bond that contains 2 electrons. If multiple lines are drawn together

More information

Check Your Solution A comparison with the figures in Figure 4.31 on page 234 of the student textbook confirms the results.

Check Your Solution A comparison with the figures in Figure 4.31 on page 234 of the student textbook confirms the results. Predicting the Shape of a Molecule (Student textbook page 236) 11. What molecular shape is represented by each of the following VSEPR notations? a. AX 3 b. AX 5 E You need to assign a molecular shape that

More information

Experiment 15. The Valence Shell Electron Pair Repulsion (VSEPR) Theory of Directed Valency: An exercise

Experiment 15. The Valence Shell Electron Pair Repulsion (VSEPR) Theory of Directed Valency: An exercise Experiment 15 The Valence Shell Electron Pair Repulsion (VSEPR) Theory of Directed Valency: An exercise Attempts to understand and predict the shapes of molecules using either the valencebond theory or

More information

(A) 1 bonding pair (B) 1 bonding pair and 1 lone pair (C) 2 bonding pairs (D) 2 bonding pairs and 2 lone pairs

(A) 1 bonding pair (B) 1 bonding pair and 1 lone pair (C) 2 bonding pairs (D) 2 bonding pairs and 2 lone pairs AP Chemistry - Problem Drill 13: Lewis Structures and VSPER No. 1 of 10 1. Lewis structure is used to model covalent bonds of a molecule or ion. Covalent bonds are a type of chemical bonding formed by

More information

This is Molecular Geometry and Covalent Bonding Models, chapter 9 from the book Principles of General Chemistry (index.html) (v. 1.0M).

This is Molecular Geometry and Covalent Bonding Models, chapter 9 from the book Principles of General Chemistry (index.html) (v. 1.0M). This is Molecular Geometry and Covalent Bonding Models, chapter 9 from the book Principles of General Chemistry (index.html) (v. 1.0M). This book is licensed under a Creative Commons by-nc-sa 3.0 (http://creativecommons.org/licenses/by-nc-sa/

More information

Chemical Bonding II. Molecular Geometry Valence Bond Theory Phys./Chem. Properties Quantum Mechanics Sigma & Pi bonds Hybridization MO theory

Chemical Bonding II. Molecular Geometry Valence Bond Theory Phys./Chem. Properties Quantum Mechanics Sigma & Pi bonds Hybridization MO theory Chemical Bonding II Molecular Geometry Valence Bond Theory Phys./Chem. Properties Quantum Mechanics Sigma & Pi bonds ybridization MO theory 1 Molecular Geometry 3-D arrangement of atoms 2 VSEPR Valence-shell

More information

Molecular Geometry and Bonding Theories. Chapter 9

Molecular Geometry and Bonding Theories. Chapter 9 Molecular Geometry and Bonding Theories Chapter 9 Molecular Shapes CCl 4 Lewis structures give atomic connectivity; The shape of a molecule is determined by its bond angles VSEPR Model Valence Shell Electron

More information

Valence Bond Theory - Description

Valence Bond Theory - Description Bonding and Molecular Structure - PART 2 - Valence Bond Theory and Hybridization 1. Understand and be able to describe the Valence Bond Theory description of covalent bond formation. 2. Understand and

More information

Covalent Bonding Introduction, 2. Chapter 7 Covalent Bonding. Figure 7.1 The Hydrogen Molecule. Outline. Covalent Bonding Introduction, 1. Figure 7.

Covalent Bonding Introduction, 2. Chapter 7 Covalent Bonding. Figure 7.1 The Hydrogen Molecule. Outline. Covalent Bonding Introduction, 1. Figure 7. Covalent Bonding Introduction, 2 William L. Masterton Cecile N. Hurley http://academic.cengage.com/chemistry/masterton Chapter 7 Covalent Bonding Electron density Electrons are located between nuclei Electrostatic

More information

Example: Write the Lewis structure of XeF 4. Example: Write the Lewis structure of I 3-. Example: Select the favored resonance structure of the PO 4

Example: Write the Lewis structure of XeF 4. Example: Write the Lewis structure of I 3-. Example: Select the favored resonance structure of the PO 4 Expanded valence shells (extended octets) more than 8e - around a central atom Extended octets are formed only by atoms with vacant d-orbitals in the valence shell (p-elements from the third or later periods)

More information

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic Orbitals Chemical Bonding II: and Hybridization of Atomic Orbitals Chapter 10 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 Valence shell electron pair repulsion (VSEPR)

More information

What is a Bond? Chapter 8. Ionic Bonding. Coulomb's Law. What about covalent compounds?

What is a Bond? Chapter 8. Ionic Bonding. Coulomb's Law. What about covalent compounds? Chapter 8 What is a Bond? A force that holds atoms together. Why? We will look at it in terms of energy. Bond energy- the energy required to break a bond. Why are compounds formed? Because it gives the

More information

4/25/2017. VSEPR Theory. Two Electron Groups. Shapes of Molecules. Two Electron Groups with Double Bonds. Three Electron Groups.

4/25/2017. VSEPR Theory. Two Electron Groups. Shapes of Molecules. Two Electron Groups with Double Bonds. Three Electron Groups. Chapter 10 Lecture Chapter 10 Bonding and Properties of Solids and Liquids 10.3 Shapes of Molecules and Ions (VSEPR Theory) Learning Goal Predict the three-dimensional structure of a molecule or a polyatomic

More information

Helpful Hints Lewis Structures Octet Rule For Lewis structures of covalent compounds least electronegative

Helpful Hints Lewis Structures Octet Rule For Lewis structures of covalent compounds least electronegative Helpful Hints Lewis Structures Octet Rule Lewis structures are a basic representation of how atoms are arranged in compounds based on bond formation by the valence electrons. A Lewis dot symbol of an atom

More information

Shapes of Molecules. Lewis structures are useful but don t allow prediction of the shape of a molecule.

Shapes of Molecules. Lewis structures are useful but don t allow prediction of the shape of a molecule. Shapes of Molecules Lewis structures are useful but don t allow prediction of the shape of a molecule. H O H H O H Can use a simple theory based on electron repulsion to predict structure (for non-transition

More information

Chapter 10. VSEPR Model: Geometries

Chapter 10. VSEPR Model: Geometries Chapter 10 Molecular Geometry VSEPR Model: Geometries Valence Shell Electron Pair Repulsion Theory Electron pairs repel and get as far apart as possible Example: Water Four electron pairs Two bonds Two

More information

Chemistry 1B Fall 2013

Chemistry 1B Fall 2013 Chemistry 1B Fall 2013 Lectures 10-11-12 1 Classical theories of bonding and molecular geometry (ch 13) Lewis electron-dot structures Bond lengths, energies and ΔH (back to pp. 615-622, much of this in

More information

Organic Chemistry. Review Information for Unit 1. VSEPR Hybrid Orbitals Polar Molecules

Organic Chemistry. Review Information for Unit 1. VSEPR Hybrid Orbitals Polar Molecules rganic hemistry Review Information for Unit 1 VSEPR ybrid rbitals Polar Molecules VSEPR The valence shell electron pair repulsion model (VSEPR) can be used to predict the geometry around a particular atom

More information

Bonding/Lewis Dots Lecture Page 1 of 12 Date. Bonding. What is Coulomb's Law? Energy Profile: Covalent Bonds. Electronegativity and Linus Pauling

Bonding/Lewis Dots Lecture Page 1 of 12 Date. Bonding. What is Coulomb's Law? Energy Profile: Covalent Bonds. Electronegativity and Linus Pauling Bonding/Lewis Dots Lecture Page 1 of 12 Date Bonding What is Coulomb's Law? Energy Profile: Covalent Bonds Electronegativity and Linus Pauling 2.1 H 1.0 Li 0.9 Na 0.8 K 0.8 Rb 0.7 Cs 0.7 Fr 1.5 Be 1.2

More information

SMK SULTAN ISMAIL JB, NUR FATHIN SUHANA BT AYOB

SMK SULTAN ISMAIL JB, NUR FATHIN SUHANA BT AYOB SMK SULTAN ISMAIL JB, NUR FATHIN SUHANA BT AYOB POLAR AND NON POLAR BONDS BOND POLARITY 1. Atoms with different electronegative from polar bonds (difference in EN) 2. Depicted as polar arrow : 3. Example

More information

Valence Shell Electron Pair repulsion

Valence Shell Electron Pair repulsion Molecular Geometry Valence Shell Electron Pair repulsion The valence shell electron pair repulsion model (VSEPR model) assumes that electron pairs repel one another. (VSEPR) model gives helps determine

More information

MOLECULAR ORBITAL DIAGRAM KEY

MOLECULAR ORBITAL DIAGRAM KEY 365 MOLECULAR ORBITAL DIAGRAM KEY Draw molecular orbital diagrams for each of the following molecules or ions. Determine the bond order of each and use this to predict the stability of the bond. Determine

More information

Theories of Covalent Bonding Molecular Geometry and Hybridization of Atomic Orbitals

Theories of Covalent Bonding Molecular Geometry and Hybridization of Atomic Orbitals Chapter 10 Theories of Covalent Bonding and ybridization of Atomic Orbitals Drawing Lewis Structures 1) Place least electronegative element as the central atom. Recognize that C,S,P and N are often central

More information

CHAPTER 5: Bonding Theories - Explaining Molecular Geometry. Chapter Outline

CHAPTER 5: Bonding Theories - Explaining Molecular Geometry. Chapter Outline CHAPTER 5: Bonding Theories - Explaining Molecular Geometry Chapter Outline 5.1 Molecular Shape 5.2 Valence-Shell Electron-Pair Repulsion Theory (VSEPR) 5.3 Polar Bonds and Polar Molecules» What Makes

More information

11/14/2014. Chemical Bonding. Richard Philips Feynman, Nobel Laureate in Physics ( )

11/14/2014. Chemical Bonding. Richard Philips Feynman, Nobel Laureate in Physics ( ) Chemical Bonding Lewis Theory Valence Bond VSEPR Molecular rbital Theory 1 "...he [his father] knew the difference between knowing the name of something and knowing something" Richard Philips eynman, Nobel

More information

Valence-Shell Electron-Pair Repulsion Theory (VSEPR)

Valence-Shell Electron-Pair Repulsion Theory (VSEPR) ; Set 09- Molecular Geometry All course materials, including lectures, class notes, quizzes, exams, handouts, presentations, and other materials provided to students for this course are protected intellectual

More information