Theme 3: Bonding and Molecular Structure. (Chapter 8)

Size: px
Start display at page:

Download "Theme 3: Bonding and Molecular Structure. (Chapter 8)"

Transcription

1 Theme 3: Bonding and Molecular Structure. (Chapter 8) End of Chapter questions: 5, 7, 9, 12, 15, 18, 23, 27, 28, 32, 33, 39, 43, 46, 67, 77 Chemical reaction valence electrons of atoms rearranged (lost, gained, reorganised) to form a net attractive force chemical bond between atoms. Ionic bond one or more valence electrons transferred from one atom to another (ions have noble gas electron configuration) creating positive and negative ions, electrostatic attraction between positive and negative ions. generally interaction of metals and non-metals. Covalent bonding involves sharing of electrons between 2 atoms, i.e. interaction between nonmetallic elements. Generally electrons are shared unequally from very little (ionic) to considerable (covalent). Lewis Symbols 2 types of electrons in atoms, i.e. core electrons that are not involved in bonding or chemical reactions, and valence electrons, i.e. electrons in the outermost electron shell of an atom, involved in bonding. Periodic Table Main groups: Group number = number of valence electrons, i.e. electrons in the s- and p-electrons in the highest n. Transition metals valence electrons include ns + (n-1)d electrons. Remaining electrons = core electrons. Lewis Dot Symbols Useful way to represent valence electrons of atom. Element symbol represents nucleus and core electrons. Valence electrons represented by dots 1st 4 placed around symbol Additional electrons paired with those already there. e.g. S: 16 electrons 1s 2 2s 2 2p 6 3s 2 3p 4 1s 2 2s 2 2p 6 = core electrons = [Ne] [Ne] 3s 2 3p 4 6 valence electrons (group 6) Main Group: valence shell can accommodate 4 pairs of electrons = 8 electrons Nobel gases (except He) have 8 electrons unreactive / inert. Octet Rule: Atoms tend to gain, lose or share electrons until they are surrounded by 8 valence e -s. Octet = full s- and p- subshells in an atom: ns 2 np 6 Ionic Bonding Na: 1s 2 2s 2 2p 6 3s 1 Cl: 1s 2 2s 2 2p 6 3s 2 3p 5 + e - Covalent Bonding: bonds result when one or more e - - pairs are shared between 2 atoms. i.e. H + H H:H each H-atom acquires 2nd electron achieves stable, noble gas configuration of He. Cl - Cl : by sharing the bonding pair each Cl atom has 8 electrons (an octet) in valence shell. Lone pairs not involved in bonding = nonbonding important for geometry. 1

2 Group 7 7 valence electrons need 1 covalent bond for octet Group 6 6 valence electrons need 2 bonds for octet e.g. H 2 O Group 5: e.g. NH 3 Questions: 1. Predict the formula of a stable binary (2 elements) compound when nitrogen reacts with fluorine. 2. Compare the Lewis symbol for Neon with the Lewis structure of methane (CH 4 ) how are they similar / different? Multiple Bonds Sharing one pair of electrons single covalent bond. Many molecules share more than one pair of electrons to obtain an octet between 2 atoms = double or triple bonds. e.g. O 2 CO 2 N 2 Bond Length General rule: bond length decreases as number of shared electrons pairs increases. N N N N N N 1.47 Å 1.24 Å 1.10 Å Lone pairs in same valence shell as bonding electrons, influence molecular geometry. Drawing Lewis electron dot Structures. Determine arrangement of atoms within molecule. Central atom for simple compounds, often 1st atom is central e.g. SO 2 usually one with lowest electronegativity (most electropositive) exceptions H 2 O, common acids (acidic H first) Hydrogen only one electron, can only make one bond = terminal position. Halogens often terminal atoms, forming one bond can be central when combined with oxygen in oxoacids (HClO 4 ) Oxygen usually terminal (central in H 2 O) 2. Write symbol of each element indicate valence electrons of each atom using dots/crosses cation place positive charge on most electropositive atom. e.g. IF 4+ - positive on I Anion place negative charge on most electronegative atom. e.g. ClF 4- - negative on F e.g. PCl 3 Place one pair of electrons between each pair of bonded atoms to form a single bond. 2

3 Central atom if less than 8 electrons, use lone pairs on terminal atoms as bonding pair for multiple bond. (Multiple bonds usually with C, N, O). e.g. Formaldehyde H 2 CO e.g. Sulphur trioxide, SO 3 Octet guideline Make single bonds all terminal atoms bound and each atom has a complete octet structure complete e.g. NH 3 If not make double bond. Check for octet. If not triple bond. Central atom has complete octet but terminal atoms not yet bonded dative covalent bond from lone pair on central atom, e.g. NH 4+ all terminal atoms bonded = structure complete. If not octet of central atom must be extended. Isoelectric Species: How are NO +, N 2, CO and CN - similar? Multiple charge spread over as many atoms as possible not placed on single atoms alone. e.g. SO 4 2- S most electropositive element central atom First make single bonds and account for lone pairs before determining whether multiple bonds are present. e.g. Nitronium ion (NO 2+ ) Formal Charge Valence electrons are not evenly distributed, as suggested by Lewis structures. Electron pairs may be drawn more strongly towards one atom in a bond making that atom slightly negative (δ-). The way electrons are distributed in a molecule, i.e. charge distribution, affects the properties of molecules. e.g. H Cl δ+ δ- δ+ end of one molecule is attracted to the δ- end of another molecule intermolecular forces affect properties of substance, i.e. boiling pt Formal charge = Group number of atom [LPE + ½ (BE)] Group number = valence electrons of atom LPE = lone pair electrons BE = bonding electrons electrons assigned by Lewis diagram Concept of formal charge helps to determine which Lewis structure is most valid not real charge, a form of bookkeeping Atom positive if contributes more electrons than it gets back. negative if contributes fewer electrons lone pairs belong to the atom to which they are allocated bonding electrons are shared between bonded atoms ( ½ BE) sum of formal charges on atoms in molecule equals the pos/neg charge on molecule/ion e.g. OH - Generally choose Lewis structure in which atoms bear formal charges closest to zero Negative charges on more electronegative atoms. 3

4 Resonance Resonance structures are used to represent bonding in a molecule/ion when a single structure fails to describe actual electronic structure accurately. e.g. ozone O 3. Ozone bonds length pm Usually average O O 132 pm and O O 121 pm Both O O bonds are the same length implies bonds are equivalent. Bond angle o < 180 o (due to presence of lone pair on central atom) Double headed arrow ( ) indicated the true structure is between the 2 extremes. e.g. Nitrate ion (NO 3- ) 3 equivalent Lewis structures. Arrangement of atoms is the same in each structure, only placement of electrons differs. Electronic structure is a hybrid of all 3 resonance structures. Formal charge on oxygen atoms = - 2 / 3 i.e. total of formal charges on O = = -2, divided by the number of O-atoms = 3 Exceptions to the Octet Rule 1. Molecules / ions containing odd numbers of electrons: e.g. ClO 2, NO, NO 2, O - 2 odd valence electrons octet not achieved NO 2 : 5 + 2(6) = 17 e - 2. Molecules / ions in which the central atom has fewer than 4 pairs (8) of electrons. e.g. Boron 3 valence electrons, forms 3 bonds valence shell with 6 electrons. Forms many compounds i.e. boric acid, B(OH) 3 ; boron trihalides, BF 3, BCl; borax, Na 2 B 4 O 5 (OH) 4.8H 2 O BF 3 Could form octet by making a B F double bond NO: = 11 e - Compounds i.e. BF 3 fairly reactive B can accommodate 4th e - - pair. Dative covalent (coordinate) bond can be formed. 3. Molecules / Ions where the central atom has more than an octet (8) of valence e-s Elements in 3rd and higher periods have ns and np and unfilled nd orbitals that can be used for bonding. e.g. PCl 5 have to expand valence shell to place 10 e-s around central phosphorus atom. Also AsF 6-, SF 4, ICl - 4 Elements of 2nd period are restricted to a maximum of 8 electrons in their compounds. Expanded valence shells occur most often when central atom is bonded to small and highly electronegative atoms, F, Cl, O. Some Lewis structures are written with an expanded valence shell, even though they can be written with an octet (giving a better group of formal charges). e.g. phosphate (PO 4 3- ) 4

5 Molecular geometry. Single central atom bonded to 2 or more atoms (of the same type) AX n A = central atom X = terminal atom/s Possible shapes depend on value of n. A main group element (s- and p- block) use VSEPR (valence shell electron-pair repulsion) model bonding and lone pair electrons in the valence shell of an element repel each other and seek to be as far apart as possible. Bonding pair e -s = defines a region in which electrons are most likely to be found = electron domain Non-bonding pair e -s (lone pairs) = electron domain located principally on one atom. e.g. NH 3 4 electron domains around central atom 3 bonding pairs and one non-bonding pair. Each multiple bond = a single electron domain O 3 : Central atom: 3 e - domains 2 bonding and 1 non-bonding. Electron domains negatively charged, therefore repel each other and try to be as far apart as possible. Best arrangement of electron domains is the one that minimises the repulsions between them: 2 e - domains arranged linearly (180 o apart) 3 e - domains trigonal planar (120 o apart) 4 e - domains tetrahedrally (109.5 o apart) 5 e - domains trigonal bipyramidal (120 o and 90 o apart) 6 e - domains octahedral (90 o apart) Shapes of AX n molecules / ions depend on the number of e - domains surrounding central A- atom. Electron pair geometry geometry of all valence electron pairs around central atom. Molecular geometry = bonding geometry arrangement in space of central atom and terminal atoms. Simplest VSEPR electron pairs around central atom involved in single covalent bonds. Linear (2 bonds) e.g. BeF 2 ; trigonal planar (3 bonds) e.g. BF 3 central atom no octet. Lone pairs on the central atom occupy spatial positions even though they are not included in the description of the shape of the molecule / ion. VSEPR model predict electron domains geometry if all electrons domains are bonded molecular geometry = electron geometry. Draw Lewis structure of molecule / ion count electron domains around central atom (i.e. nonbonding pairs, single bonds, double bonds) Determine electron domain geometry arrange electron domains around central atom to minimise repulsions. Use arrangement of bonded atoms to determine molecular geometry. Trigonal Planar: AX 3 e.g. BF 3 / CO 3 2- e.g. O 3 5

6 Four electron domains: Tetrahedral electron geometry AX 4 e.g. CH 4 e.g. NH 3 e.g. Cl 2 F + Molecules with expanded valence shell: Five electron domains Trigonal bipyramidal electron geometry AX 5 2 sets of positions that are not equivalent 3 equatorial electron domains define and equatorial triangle 2 axial electron domains north and south poles of molecule Each axial domain 90 o from equatorial domain Each equatorial domain 120 o from other equatorial domains and 90 o from axial domains. Repulsions between domains at 90 o from each other are greater than when angle is 120 o. Equatorial domain experiences less repulsion Lone pairs exert larger repulsions will occupy equatorial positions double bonds have greater electron density more repulsion equatorial position. If terminal atoms differ more electronegative in axial positions (bonds will be longer). e.g. PCl 5 : SF 4 : ClF 3 : XeF 2 : Six electron domains most stable geometry is octahedral (6 vertices) All bond angles are 90 o All six vertices are equivalent non-bonding domain can be placed in any position 2 non-bonding domains placed opposite each other to minimise repulsion e.g. SF 6 : IF 5 : ICl 4- : Bond Angles Effect of non-bonding electrons and multiple bonds. Electron pair geometry of NH 3 is tetrahedral expect bond angle to be o experimentally o. Electron pair geometry of H 2 O also tetrahedral experimental bond angle o Bond angle decreases with increasing number of non-bonding electrons. Bonding electron pair attracted by both nuclei of bonded atoms. Lone pair attracted by only one nucleus electron domain more spread out exert a greater repulsive force on adjacent electron domains (compress bond angles). Multiple bonds also contain a higher electron charge density than single bonds also larger electron domains. Relative strength of repulsions: Lone pair lone pair > lone pair bonding pair > bonding pair bonding pair Q. NO 3 ion bond angles = 120 o is this what is expected? 6

AP Chemistry A. Allan Chapter 8 Notes - Bonding: General Concepts

AP Chemistry A. Allan Chapter 8 Notes - Bonding: General Concepts AP Chemistry A. Allan Chapter 8 Notes - Bonding: General Concepts 8.1 Types of Chemical Bonds A. Ionic Bonding 1. Electrons are transferred 2. Metals react with nonmetals 3. Ions paired have lower energy

More information

EXPERIMENT 17 : Lewis Dot Structure / VSEPR Theory

EXPERIMENT 17 : Lewis Dot Structure / VSEPR Theory EXPERIMENT 17 : Lewis Dot Structure / VSEPR Theory Materials: Molecular Model Kit INTRODUCTION Although it has recently become possible to image molecules and even atoms using a high-resolution microscope,

More information

Question 4.2: Write Lewis dot symbols for atoms of the following elements: Mg, Na, B, O, N, Br.

Question 4.2: Write Lewis dot symbols for atoms of the following elements: Mg, Na, B, O, N, Br. Question 4.1: Explain the formation of a chemical bond. A chemical bond is defined as an attractive force that holds the constituents (atoms, ions etc.) together in a chemical species. Various theories

More information

EXPERIMENT 9 Dot Structures and Geometries of Molecules

EXPERIMENT 9 Dot Structures and Geometries of Molecules EXPERIMENT 9 Dot Structures and Geometries of Molecules INTRODUCTION Lewis dot structures are our first tier in drawing molecules and representing bonds between the atoms. The method was first published

More information

Laboratory 11: Molecular Compounds and Lewis Structures

Laboratory 11: Molecular Compounds and Lewis Structures Introduction Laboratory 11: Molecular Compounds and Lewis Structures Molecular compounds are formed by sharing electrons between non-metal atoms. A useful theory for understanding the formation of molecular

More information

Vocabulary: VSEPR. 3 domains on central atom. 2 domains on central atom. 3 domains on central atom NOTE: Valence Shell Electron Pair Repulsion Theory

Vocabulary: VSEPR. 3 domains on central atom. 2 domains on central atom. 3 domains on central atom NOTE: Valence Shell Electron Pair Repulsion Theory Vocabulary: VSEPR Valence Shell Electron Pair Repulsion Theory domain = any electron pair, or any double or triple bond is considered one domain. lone pair = non-bonding pair = unshared pair = any electron

More information

Molecular Geometry and VSEPR We gratefully acknowledge Portland Community College for the use of this experiment.

Molecular Geometry and VSEPR We gratefully acknowledge Portland Community College for the use of this experiment. Molecular and VSEPR We gratefully acknowledge Portland ommunity ollege for the use of this experiment. Objectives To construct molecular models for covalently bonded atoms in molecules and polyatomic ions

More information

Chapter 7. Comparing Ionic and Covalent Bonds. Ionic Bonds. Types of Bonds. Quick Review of Bond Types. Covalent Bonds

Chapter 7. Comparing Ionic and Covalent Bonds. Ionic Bonds. Types of Bonds. Quick Review of Bond Types. Covalent Bonds Comparing Ionic and Covalent Bonds Chapter 7 Covalent Bonds and Molecular Structure Intermolecular forces (much weaker than bonds) must be broken Ionic bonds must be broken 1 Ionic Bonds Covalent Bonds

More information

CHEMISTRY BONDING REVIEW

CHEMISTRY BONDING REVIEW Answer the following questions. CHEMISTRY BONDING REVIEW 1. What are the three kinds of bonds which can form between atoms? The three types of Bonds are Covalent, Ionic and Metallic. Name Date Block 2.

More information

A pure covalent bond is an equal sharing of shared electron pair(s) in a bond. A polar covalent bond is an unequal sharing.

A pure covalent bond is an equal sharing of shared electron pair(s) in a bond. A polar covalent bond is an unequal sharing. CHAPTER EIGHT BNDING: GENERAL CNCEPT or Review 1. Electronegativity is the ability of an atom in a molecule to attract electrons to itself. Electronegativity is a bonding term. Electron affinity is the

More information

5. Structure, Geometry, and Polarity of Molecules

5. Structure, Geometry, and Polarity of Molecules 5. Structure, Geometry, and Polarity of Molecules What you will accomplish in this experiment This experiment will give you an opportunity to draw Lewis structures of covalent compounds, then use those

More information

The Lewis structure is a model that gives a description of where the atoms, charges, bonds, and lone pairs of electrons, may be found.

The Lewis structure is a model that gives a description of where the atoms, charges, bonds, and lone pairs of electrons, may be found. CEM110 Week 12 Notes (Chemical Bonding) Page 1 of 8 To help understand molecules (or radicals or ions), VSEPR shapes, and properties (such as polarity and bond length), we will draw the Lewis (or electron

More information

C has 4 valence electrons, O has six electrons. The total number of electrons is 4 + 2(6) = 16.

C has 4 valence electrons, O has six electrons. The total number of electrons is 4 + 2(6) = 16. 129 Lewis Structures G. N. Lewis hypothesized that electron pair bonds between unlike elements in the second (and sometimes the third) row occurred in a way that electrons were shared such that each element

More information

Chapter 8 Concepts of Chemical Bonding

Chapter 8 Concepts of Chemical Bonding Chapter 8 Concepts of Chemical Bonding Chemical Bonds Three types: Ionic Electrostatic attraction between ions Covalent Sharing of electrons Metallic Metal atoms bonded to several other atoms Ionic Bonding

More information

We emphasize Lewis electron dot structures because of their usefulness in explaining structure of covalent molecules, especially organic molecules.

We emphasize Lewis electron dot structures because of their usefulness in explaining structure of covalent molecules, especially organic molecules. Chapter 10 Bonding: Lewis electron dot structures and more Bonding is the essence of chemistry! Not just physics! Chemical bonds are the forces that hold atoms together in molecules, in ionic compounds,

More information

2. Atoms with very similar electronegativity values are expected to form

2. Atoms with very similar electronegativity values are expected to form AP hemistry Practice Test #6 hapter 8 and 9 1. Which of the following statements is incorrect? a. Ionic bonding results from the transfer of electrons from one atom to another. b. Dipole moments result

More information

Sample Exercise 8.1 Magnitudes of Lattice Energies

Sample Exercise 8.1 Magnitudes of Lattice Energies Sample Exercise 8.1 Magnitudes of Lattice Energies Without consulting Table 8.2, arrange the ionic compounds NaF, CsI, and CaO in order of increasing lattice energy. Analyze From the formulas for three

More information

Self Assessment_Ochem I

Self Assessment_Ochem I UTID: 2013 Objective Test Section Identify the choice that best completes the statement or answers the question. There is only one correct answer; please carefully bubble your choice on the scantron sheet.

More information

Sample Exercise 8.1 Magnitudes of Lattice Energies

Sample Exercise 8.1 Magnitudes of Lattice Energies Sample Exercise 8.1 Magnitudes of Lattice Energies Without consulting Table 8.2, arrange the following ionic compounds in order of increasing lattice energy: NaF, CsI, and CaO. Analyze: From the formulas

More information

CHEM 1301 SECOND TEST REVIEW. Covalent bonds are sharing of electrons (ALWAYS valence electrons). Use Lewis structures to show this sharing.

CHEM 1301 SECOND TEST REVIEW. Covalent bonds are sharing of electrons (ALWAYS valence electrons). Use Lewis structures to show this sharing. CEM 1301 SECOND TEST REVIEW Lewis Structures Covalent bonds are sharing of electrons (ALWAYS valence electrons). Use Lewis structures to show this sharing. Rules OCTET RULE an atom would like to have 8

More information

Ionic and Covalent Bonds

Ionic and Covalent Bonds Ionic and Covalent Bonds Ionic Bonds Transfer of Electrons When metals bond with nonmetals, electrons are from the metal to the nonmetal The becomes a cation and the becomes an anion. The between the cation

More information

Chemistry Workbook 2: Problems For Exam 2

Chemistry Workbook 2: Problems For Exam 2 Chem 1A Dr. White Updated /5/1 1 Chemistry Workbook 2: Problems For Exam 2 Section 2-1: Covalent Bonding 1. On a potential energy diagram, the most stable state has the highest/lowest potential energy.

More information

Molecular Geometry and Chemical Bonding Theory

Molecular Geometry and Chemical Bonding Theory Chapter 10 Molecular Geometry and Chemical Bonding Theory Concept Check 10.1 An atom in a molecule is surrounded by four pairs of electrons, one lone pair and three bonding pairs. Describe how the four

More information

Bonding Models. Bonding Models (Lewis) Bonding Models (Lewis) Resonance Structures. Section 2 (Chapter 3, M&T) Chemical Bonding

Bonding Models. Bonding Models (Lewis) Bonding Models (Lewis) Resonance Structures. Section 2 (Chapter 3, M&T) Chemical Bonding Bonding Models Section (Chapter, M&T) Chemical Bonding We will look at three models of bonding: Lewis model Valence Bond model M theory Bonding Models (Lewis) Bonding Models (Lewis) Lewis model of bonding

More information

SOME TOUGH COLLEGE PROBLEMS! .. : 4. How many electrons should be shown in the Lewis dot structure for carbon monoxide? N O O

SOME TOUGH COLLEGE PROBLEMS! .. : 4. How many electrons should be shown in the Lewis dot structure for carbon monoxide? N O O SME TUGH CLLEGE PRBLEMS! LEWIS DT STRUCTURES 1. An acceptable Lewis dot structure for 2 is (A) (B) (C) 2. Which molecule contains one unshared pair of valence electrons? (A) H 2 (B) H 3 (C) CH 4 acl 3.

More information

ch9 and 10 practice test

ch9 and 10 practice test 1. Which of the following covalent bonds is the most polar (highest percent ionic character)? A. Al I B. Si I C. Al Cl D. Si Cl E. Si P 2. What is the hybridization of the central atom in ClO 3? A. sp

More information

7.14 Linear triatomic: A-----B-----C. Bond angles = 180 degrees. Trigonal planar: Bond angles = 120 degrees. B < B A B = 120

7.14 Linear triatomic: A-----B-----C. Bond angles = 180 degrees. Trigonal planar: Bond angles = 120 degrees. B < B A B = 120 APTER SEVEN Molecular Geometry 7.13 Molecular geometry may be defined as the three-dimensional arrangement of atoms in a molecule. The study of molecular geometry is important in that a molecule s geometry

More information

Chapter 9. Chemical reactivity of molecules depends on the nature of the bonds between the atoms as well on its 3D structure

Chapter 9. Chemical reactivity of molecules depends on the nature of the bonds between the atoms as well on its 3D structure Chapter 9 Molecular Geometry & Bonding Theories I) Molecular Geometry (Shapes) Chemical reactivity of molecules depends on the nature of the bonds between the atoms as well on its 3D structure Molecular

More information

CHAPTER 6 REVIEW. Chemical Bonding. Answer the following questions in the space provided.

CHAPTER 6 REVIEW. Chemical Bonding. Answer the following questions in the space provided. Name Date lass APTER 6 REVIEW hemical Bonding SETIN 1 SRT ANSWER Answer the following questions in the space provided. 1. a A chemical bond between atoms results from the attraction between the valence

More information

Covalent Bonding and Molecular Geometry

Covalent Bonding and Molecular Geometry Name Section # Date of Experiment Covalent Bonding and Molecular Geometry When atoms combine to form molecules (this also includes complex ions) by forming covalent bonds, the relative positions of the

More information

CHAPTER 12: CHEMICAL BONDING

CHAPTER 12: CHEMICAL BONDING CHAPTER 12: CHEMICAL BONDING Active Learning Questions: 3-9, 11-19, 21-22 End-of-Chapter Problems: 1-36, 41-59, 60(a,b), 61(b,d), 62(a,b), 64-77, 79-89, 92-101, 106-109, 112, 115-119 An American chemist

More information

CH101/105, GENERAL CHEMISTRY LABORATORY

CH101/105, GENERAL CHEMISTRY LABORATORY CH101/105, GENERAL CHEMITRY LABORATORY LABORATORY LECTURE 5 EXPERIMENT 5: LEWI TRUCTURE AND MOLECULAR HAPE Lecture topics I. LEWI TRUCTURE a) calculation of the valence electron numbers; b) choosing the

More information

SHAPES OF MOLECULES (VSEPR MODEL)

SHAPES OF MOLECULES (VSEPR MODEL) 1 SAPES MLEULES (VSEPR MDEL) Valence Shell Electron-Pair Repulsion model - Electron pairs surrounding atom spread out as to minimize repulsion. - Electron pairs can be bonding pairs (including multiple

More information

Chemical Bonding: Covalent Systems Written by Rebecca Sunderman, Ph.D Week 1, Winter 2012, Matter & Motion

Chemical Bonding: Covalent Systems Written by Rebecca Sunderman, Ph.D Week 1, Winter 2012, Matter & Motion Chemical Bonding: Covalent Systems Written by Rebecca Sunderman, Ph.D Week 1, Winter 2012, Matter & Motion A covalent bond is a bond formed due to a sharing of electrons. Lewis structures provide a description

More information

A mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together is called a(n)

A mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together is called a(n) Chemistry I ATOMIC BONDING PRACTICE QUIZ Mr. Scott Select the best answer. 1) A mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together is

More information

LEWIS DIAGRAMS. by DR. STEPHEN THOMPSON MR. JOE STALEY

LEWIS DIAGRAMS. by DR. STEPHEN THOMPSON MR. JOE STALEY by DR. STEPHEN THOMPSON MR. JOE STALEY The contents of this module were developed under grant award # P116B-001338 from the Fund for the Improvement of Postsecondary Education (FIPSE), United States Department

More information

Exercises Topic 2: Molecules

Exercises Topic 2: Molecules hemistry for Biomedical Engineering. Exercises Topic 2 Authors: ors: Juan Baselga & María González Exercises Topic 2: Molecules 1. Using hybridization concepts and VSEPR model describe the molecular geometry

More information

Bonding Practice Problems

Bonding Practice Problems NAME 1. When compared to H 2 S, H 2 O has a higher 8. Given the Lewis electron-dot diagram: boiling point because H 2 O contains stronger metallic bonds covalent bonds ionic bonds hydrogen bonds 2. Which

More information

Health Science Chemistry I CHEM-1180 Experiment No. 15 Molecular Models (Revised 05/22/2015)

Health Science Chemistry I CHEM-1180 Experiment No. 15 Molecular Models (Revised 05/22/2015) (Revised 05/22/2015) Introduction In the early 1900s, the chemist G. N. Lewis proposed that bonds between atoms consist of two electrons apiece and that most atoms are able to accommodate eight electrons

More information

Bonding & Molecular Shape Ron Robertson

Bonding & Molecular Shape Ron Robertson Bonding & Molecular Shape Ron Robertson r2 n:\files\courses\1110-20\2010 possible slides for web\00bondingtrans.doc The Nature of Bonding Types 1. Ionic 2. Covalent 3. Metallic 4. Coordinate covalent Driving

More information

CHAPTER 6 Chemical Bonding

CHAPTER 6 Chemical Bonding CHAPTER 6 Chemical Bonding SECTION 1 Introduction to Chemical Bonding OBJECTIVES 1. Define Chemical bond. 2. Explain why most atoms form chemical bonds. 3. Describe ionic and covalent bonding.. 4. Explain

More information

VSEPR Model. The Valence-Shell Electron Pair Repulsion Model. Predicting Molecular Geometry

VSEPR Model. The Valence-Shell Electron Pair Repulsion Model. Predicting Molecular Geometry VSEPR Model The structure around a given atom is determined principally by minimizing electron pair repulsions. The Valence-Shell Electron Pair Repulsion Model The valence-shell electron pair repulsion

More information

: : Solutions to Additional Bonding Problems

: : Solutions to Additional Bonding Problems Solutions to Additional Bonding Problems 1 1. For the following examples, the valence electron count is placed in parentheses after the empirical formula and only the resonance structures that satisfy

More information

Structures and Properties of Substances. Introducing Valence-Shell Electron- Pair Repulsion (VSEPR) Theory

Structures and Properties of Substances. Introducing Valence-Shell Electron- Pair Repulsion (VSEPR) Theory Structures and Properties of Substances Introducing Valence-Shell Electron- Pair Repulsion (VSEPR) Theory The VSEPR theory In 1957, the chemist Ronald Gillespie and Ronald Nyholm, developed a model for

More information

ACE PRACTICE TEST Chapter 8, Quiz 3

ACE PRACTICE TEST Chapter 8, Quiz 3 ACE PRACTICE TEST Chapter 8, Quiz 3 1. Using bond energies, calculate the heat in kj for the following reaction: CH 4 + 4 F 2 CF 4 + 4 HF. Use the following bond energies: CH = 414 kj/mol, F 2 = 155 kj/mol,

More information

Chapter10 Tro. 4. Based on the Lewis structure, the number of electron domains in the valence shell of the CO molecule is A) 1 B) 2 C) 3 D) 4 E) 5

Chapter10 Tro. 4. Based on the Lewis structure, the number of electron domains in the valence shell of the CO molecule is A) 1 B) 2 C) 3 D) 4 E) 5 Chapter10 Tro 1. All of the geometries listed below are examples of the five basic geometries for molecules with more than 3 atoms except A) planar triangular B) octahedral C) tetrahedral D) trihedral

More information

Chapter 8 Basic Concepts of the Chemical Bonding

Chapter 8 Basic Concepts of the Chemical Bonding Chapter 8 Basic Concepts of the Chemical Bonding 1. There are paired and unpaired electrons in the Lewis symbol for a phosphorus atom. (a). 4, 2 (b). 2, 4 (c). 4, 3 (d). 2, 3 Explanation: Read the question

More information

6.5 Periodic Variations in Element Properties

6.5 Periodic Variations in Element Properties 324 Chapter 6 Electronic Structure and Periodic Properties of Elements 6.5 Periodic Variations in Element Properties By the end of this section, you will be able to: Describe and explain the observed trends

More information

4.2. Molecular Shape and Polarity. Lewis Structures for Molecules and Polyatomic Ions

4.2. Molecular Shape and Polarity. Lewis Structures for Molecules and Polyatomic Ions Molecular Shape and Polarity 4.2 molecule is a discrete chemical entity, in which atoms are held together by the electrostatic attractions of covalent bonds. In previous chemistry courses, you used Lewis

More information

CHAPTER 10 THE SHAPES OF MOLECULES

CHAPTER 10 THE SHAPES OF MOLECULES ATER 10 TE AE MLEULE 10.1 To be the central atom in a compound, the atom must be able to simultaneously bond to at least two other atoms. e,, and cannot serve as central atoms in a Lewis structure. elium

More information

Chapter 10 Molecular Geometry and Chemical Bonding Theory

Chapter 10 Molecular Geometry and Chemical Bonding Theory Chem 1: Chapter 10 Page 1 Chapter 10 Molecular Geometry and Chemical Bonding Theory I) VSEPR Model Valence-Shell Electron-Pair Repulsion Model A) Model predicts Predicts electron arrangement and molecular

More information

Questions on Chapter 8 Basic Concepts of Chemical Bonding

Questions on Chapter 8 Basic Concepts of Chemical Bonding Questions on Chapter 8 Basic Concepts of Chemical Bonding Circle the Correct Answer: 1) Which ion below has a noble gas electron configuration? A) Li 2+ B) Be 2+ C) B2+ D) C2+ E) N 2-2) Of the ions below,

More information

Chapter 8: Covalent Bonding and Molecular Structure

Chapter 8: Covalent Bonding and Molecular Structure hapter 8 ovalent Bonding and Molecular Structure 8-1 hapter 8: ovalent Bonding and Molecular Structure hapter 8 8.1 Interactions Between Particles: oulomb s Law 8.2 ovalent Bonding Basics 8.3 Lewis Structures

More information

Lewis Dot Notation Ionic Bonds Covalent Bonds Polar Covalent Bonds Lewis Dot Notation Revisited Resonance

Lewis Dot Notation Ionic Bonds Covalent Bonds Polar Covalent Bonds Lewis Dot Notation Revisited Resonance Lewis Dot Notation Ionic Bonds Covalent Bonds Polar Covalent Bonds Lewis Dot Notation Revisited Resonance Lewis Dot notation is a way of describing the outer shell (also called the valence shell) of an

More information

Name: Class: Date: 3) The bond angles marked a, b, and c in the molecule below are about,, and, respectively.

Name: Class: Date: 3) The bond angles marked a, b, and c in the molecule below are about,, and, respectively. Name: Class: Date: Unit 9 Practice Multiple Choice Identify the choice that best completes the statement or answers the question. 1) The basis of the VSEPR model of molecular bonding is. A) regions of

More information

Unit 3: Quantum Theory, Periodicity and Chemical Bonding

Unit 3: Quantum Theory, Periodicity and Chemical Bonding Selected Honour Chemistry Assignment Answers pg. 9 Unit 3: Quantum Theory, Periodicity and Chemical Bonding Chapter 7: The Electronic Structure of Atoms (pg. 240 to 241) 48. The shape of an s-orbital is

More information

Chapter 2 The Chemical Context of Life

Chapter 2 The Chemical Context of Life Chapter 2 The Chemical Context of Life Multiple-Choice Questions 1) About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living

More information

Worksheet 14 - Lewis structures. 1. Complete the Lewis dot symbols for the oxygen atoms below

Worksheet 14 - Lewis structures. 1. Complete the Lewis dot symbols for the oxygen atoms below Worksheet 14 - Lewis structures Determine the Lewis structure of 2 oxygen gas. 1. omplete the Lewis dot symbols for the oxygen atoms below 2. Determine the number of valence electrons available in the

More information

CHAPTER 10 THE SHAPES OF MOLECULES

CHAPTER 10 THE SHAPES OF MOLECULES ATER 10 TE AE MLEULE EMIAL ETI BED READIG RBLEM B10.1 lan: Examine the Lewis structure, noting the number of regions of electron density around the carbon and nitrogen atoms in the two resonance structures.

More information

5. Which of the following is the correct Lewis structure for SOCl 2

5. Which of the following is the correct Lewis structure for SOCl 2 Unit C Practice Problems Chapter 8 1. Draw the lewis structures for the following molecules: a. BeF 2 b. SO 3 c. CNS 1- d. NO 2. The correct Lewis symbol for ground state carbon is a) b) c) d) e) 3. Which

More information

OCTET RULE Generally atoms prefer electron configurations with 8 valence electrons. - Filled s and p subshells

OCTET RULE Generally atoms prefer electron configurations with 8 valence electrons. - Filled s and p subshells TYPES EMIAL BDIG 1 Ionic Bonding - Bond between ions whose charges attract each other - ne atom gives electrons and one atom takes electrons. Example a + l - ionic bond ovalent Bonding - two atoms each

More information

Test Bank - Chapter 4 Multiple Choice

Test Bank - Chapter 4 Multiple Choice Test Bank - Chapter 4 The questions in the test bank cover the concepts from the lessons in Chapter 4. Select questions from any of the categories that match the content you covered with students. The

More information

Chapter 4: Structure and Properties of Ionic and Covalent Compounds

Chapter 4: Structure and Properties of Ionic and Covalent Compounds Chapter 4: Structure and Properties of Ionic and Covalent Compounds 4.1 Chemical Bonding o Chemical Bond - the force of attraction between any two atoms in a compound. o Interactions involving valence

More information

Chem 121 Problem Set V Lewis Structures, VSEPR and Polarity

Chem 121 Problem Set V Lewis Structures, VSEPR and Polarity hemistry 121 Problem set V olutions - 1 hem 121 Problem et V Lewis tructures, VEPR and Polarity AWER 1. pecies Elecronegativity difference in bond Bond Polarity Mp 3 E = 3.0-3.0 = 0 for - very weakly polar

More information

A REVIEW OF GENERAL CHEMISTRY: ELECTRONS, BONDS AND MOLECULAR PROPERTIES

A REVIEW OF GENERAL CHEMISTRY: ELECTRONS, BONDS AND MOLECULAR PROPERTIES A REVIEW OF GENERAL CEMISTRY: ELECTRONS, BONDS AND MOLECULAR PROPERTIES A STUDENT SOULD BE ABLE TO: 1. Draw Lewis (electron dot and line) structural formulas for simple compounds and ions from molecular

More information

Elements in the periodic table are indicated by SYMBOLS. To the left of the symbol we find the atomic mass (A) at the upper corner, and the atomic num

Elements in the periodic table are indicated by SYMBOLS. To the left of the symbol we find the atomic mass (A) at the upper corner, and the atomic num . ATOMIC STRUCTURE FUNDAMENTALS LEARNING OBJECTIVES To review the basics concepts of atomic structure that have direct relevance to the fundamental concepts of organic chemistry. This material is essential

More information

3) Of the following, radiation has the shortest wavelength. A) X-ray B) radio C) microwave D) ultraviolet E) infrared Answer: A

3) Of the following, radiation has the shortest wavelength. A) X-ray B) radio C) microwave D) ultraviolet E) infrared Answer: A 1) Which one of the following is correct? A) ν + λ = c B) ν λ = c C) ν = cλ D) λ = c ν E) νλ = c Answer: E 2) The wavelength of light emitted from a traffic light having a frequency of 5.75 1014 Hz is.

More information

Which substance contains positive ions immersed in a sea of mobile electrons? A) O2(s) B) Cu(s) C) CuO(s) D) SiO2(s)

Which substance contains positive ions immersed in a sea of mobile electrons? A) O2(s) B) Cu(s) C) CuO(s) D) SiO2(s) BONDING MIDTERM REVIEW 7546-1 - Page 1 1) Which substance contains positive ions immersed in a sea of mobile electrons? A) O2(s) B) Cu(s) C) CuO(s) D) SiO2(s) 2) The bond between hydrogen and oxygen in

More information

Molecular Geometry & Polarity

Molecular Geometry & Polarity Name AP Chemistry Molecular Geometry & Polarity Molecular Geometry A key to understanding the wide range of physical and chemical properties of substances is recognizing that atoms combine with other atoms

More information

Chapter 2 Polar Covalent Bonds; Acids and Bases

Chapter 2 Polar Covalent Bonds; Acids and Bases John E. McMurry http://www.cengage.com/chemistry/mcmurry Chapter 2 Polar Covalent Bonds; Acids and Bases Javier E. Horta, M.D., Ph.D. University of Massachusetts Lowell Polar Covalent Bonds: Electronegativity

More information

List the 3 main types of subatomic particles and indicate the mass and electrical charge of each.

List the 3 main types of subatomic particles and indicate the mass and electrical charge of each. Basic Chemistry Why do we study chemistry in a biology course? All living organisms are composed of chemicals. To understand life, we must understand the structure, function, and properties of the chemicals

More information

We will not be doing these type of calculations however, if interested then can read on your own

We will not be doing these type of calculations however, if interested then can read on your own Chemical Bond Lattice Energies and Types of Ions Na (s) + 1/2Cl 2 (g) NaCl (s) ΔH= -411 kj/mol Energetically favored: lower energy Like a car rolling down a hill We will not be doing these type of calculations

More information

AS Chemistry Revision Notes Unit 1 Atomic Structure, Bonding And Periodicity

AS Chemistry Revision Notes Unit 1 Atomic Structure, Bonding And Periodicity AS Chemistry Revision Notes Unit Atomic Structure, Bonding And Periodicity Atomic Structure. All atoms have a mass number, A (the number of nucleons), and a proton number, Z (the number of protons). 2.

More information

The elements of the second row fulfill the octet rule by sharing eight electrons, thus acquiring the electronic configuration of neon, the noble gas o

The elements of the second row fulfill the octet rule by sharing eight electrons, thus acquiring the electronic configuration of neon, the noble gas o 2. VALENT BNDING, TET RULE, PLARITY, AND BASI TYPES F FRMULAS LEARNING BJETIVES To introduce the basic principles of covalent bonding, different types of molecular representations, bond polarity and its

More information

Chapter 1 Structure and Bonding. Modified by Dr. Daniela Radu

Chapter 1 Structure and Bonding. Modified by Dr. Daniela Radu John E. McMurry www.cengage.com/chemistry/mcmurry Chapter 1 Structure and Bonding Modified by Dr. Daniela Radu What is Organic Chemistry? Living things are made of organic chemicals Proteins that make

More information

Molecular Models in Biology

Molecular Models in Biology Molecular Models in Biology Objectives: After this lab a student will be able to: 1) Understand the properties of atoms that give rise to bonds. 2) Understand how and why atoms form ions. 3) Model covalent,

More information

CHAPTER 10 THE SHAPES OF MOLECULES

CHAPTER 10 THE SHAPES OF MOLECULES ATER 10 TE AE MLEULE 10.1 To be the central atom in a compound, the atom must be able to simultaneously bond to at least two other atoms. e,, and cannot serve as central atoms in a Lewis structure. elium

More information

CHEM 1211K Test IV. MULTIPLE CHOICE (3 points each)

CHEM 1211K Test IV. MULTIPLE CHOICE (3 points each) CEM 1211K Test IV MULTIPLE COICE (3 points each) 1) ow many single covalent bonds must a silicon atom form to have a complete octet in its valence shell? A) 4 B) 3 C) 1 D) 2 E) 0 2) What is the maximum

More information

Chapter 5 TEST: The Periodic Table name

Chapter 5 TEST: The Periodic Table name Chapter 5 TEST: The Periodic Table name HPS # date: Multiple Choice Identify the choice that best completes the statement or answers the question. 1. The order of elements in the periodic table is based

More information

CHEMISTRY 1710 - Practice Exam #5 - SPRING 2014 (KATZ)

CHEMISTRY 1710 - Practice Exam #5 - SPRING 2014 (KATZ) CHEMISTRY 1710 - Practice Exam #5 - SPRING 2014 (KATZ) Name: Score: This is a multiple choice exam. Choose the BEST answer from the choices which are given and write the letter for your choice in the space

More information

Molecular Models & Lewis Dot Structures

Molecular Models & Lewis Dot Structures Molecular Models & Lewis Dot Structures Objectives: 1. Draw Lewis structures for atoms, ions and simple molecules. 2. Use Lewis structures as a guide to construct three-dimensional models of small molecules.

More information

7.4. Using the Bohr Theory KNOW? Using the Bohr Theory to Describe Atoms and Ions

7.4. Using the Bohr Theory KNOW? Using the Bohr Theory to Describe Atoms and Ions 7.4 Using the Bohr Theory LEARNING TIP Models such as Figures 1 to 4, on pages 218 and 219, help you visualize scientific explanations. As you examine Figures 1 to 4, look back and forth between the diagrams

More information

Chemistry 151 Final Exam

Chemistry 151 Final Exam Chemistry 151 Final Exam Name: SSN: Exam Rules & Guidelines Show your work. No credit will be given for an answer unless your work is shown. Indicate your answer with a box or a circle. All paperwork must

More information

2. Which one of the ions below possesses a noble gas configuration? A) Fe 3+ B) Sn 2+ C) Ni 2+ D) Ti 4+ E) Cr 3+

2. Which one of the ions below possesses a noble gas configuration? A) Fe 3+ B) Sn 2+ C) Ni 2+ D) Ti 4+ E) Cr 3+ Chapter 9 Tro 1. Bromine tends to form simple ions which have the electronic configuration of a noble gas. What is the electronic configuration of the noble gas which the bromide ion mimics? A) 1s 2 2s

More information

SCPS Chemistry Worksheet Periodicity A. Periodic table 1. Which are metals? Circle your answers: C, Na, F, Cs, Ba, Ni

SCPS Chemistry Worksheet Periodicity A. Periodic table 1. Which are metals? Circle your answers: C, Na, F, Cs, Ba, Ni SCPS Chemistry Worksheet Periodicity A. Periodic table 1. Which are metals? Circle your answers: C, Na, F, Cs, Ba, Ni Which metal in the list above has the most metallic character? Explain. Cesium as the

More information

Molecular Structure and Polarity

Molecular Structure and Polarity OpenStax-CNX module: m51053 1 Molecular Structure and Polarity OpenStax College This work is produced by OpenStax-CNX and licensed under the Creative Commons Attribution License 4.0 By the end of this

More information

Start: 26e Used: 6e Step 4. Place the remaining valence electrons as lone pairs on the surrounding and central atoms.

Start: 26e Used: 6e Step 4. Place the remaining valence electrons as lone pairs on the surrounding and central atoms. Section 4.1: Types of Chemical Bonds Tutorial 1 Practice, page 200 1. (a) Lewis structure for NBr 3 : Step 1. The central atom for nitrogen tribromide is bromine. 1 N atom: 1(5e ) = 5e 3 Br atoms: 3(7e

More information

Valence Bond Theory: Hybridization

Valence Bond Theory: Hybridization Exercise 13 Page 1 Illinois Central College CEMISTRY 130 Laboratory Section: Valence Bond Theory: ybridization Name: Objectives To illustrate the distribution of electrons and rearrangement of orbitals

More information

In the box below, draw the Lewis electron-dot structure for the compound formed from magnesium and oxygen. [Include any charges or partial charges.

In the box below, draw the Lewis electron-dot structure for the compound formed from magnesium and oxygen. [Include any charges or partial charges. Name: 1) Which molecule is nonpolar and has a symmetrical shape? A) NH3 B) H2O C) HCl D) CH4 7222-1 - Page 1 2) When ammonium chloride crystals are dissolved in water, the temperature of the water decreases.

More information

Ionic and Metallic Bonding

Ionic and Metallic Bonding Ionic and Metallic Bonding BNDING AND INTERACTINS 71 Ions For students using the Foundation edition, assign problems 1, 3 5, 7 12, 14, 15, 18 20 Essential Understanding Ions form when atoms gain or lose

More information

Part I: Principal Energy Levels and Sublevels

Part I: Principal Energy Levels and Sublevels Part I: Principal Energy Levels and Sublevels As you already know, all atoms are made of subatomic particles, including protons, neutrons, and electrons. Positive protons and neutral neutrons are found

More information

Covalent Bonding & Molecular Compounds Multiple Choice Review PSI Chemistry

Covalent Bonding & Molecular Compounds Multiple Choice Review PSI Chemistry Covalent Bonding & Molecular Compounds Multiple Choice Review PSI Chemistry Name 1) Which pair of elements is most apt to form a molecular compound with each other? A) aluminum, oxygen B) magnesium, iodine

More information

7) How many electrons are in the second energy level for an atom of N? A) 5 B) 6 C) 4 D) 8

7) How many electrons are in the second energy level for an atom of N? A) 5 B) 6 C) 4 D) 8 HOMEWORK CHEM 107 Chapter 3 Compounds Putting Particles Together 3.1 Multiple-Choice 1) How many electrons are in the highest energy level of sulfur? A) 2 B) 4 C) 6 D) 8 2) An atom of phosphorous has how

More information

Molecular Structures. Chapter 9 Molecular Structures. Using Molecular Models. Using Molecular Models. C 2 H 6 O structural isomers: .. H C C O..

Molecular Structures. Chapter 9 Molecular Structures. Using Molecular Models. Using Molecular Models. C 2 H 6 O structural isomers: .. H C C O.. John W. Moore onrad L. Stanitski Peter. Jurs http://academic.cengage.com/chemistry/moore hapter 9 Molecular Structures Stephen. oster Mississippi State University Molecular Structures 2 6 structural isomers:

More information

Unit 3: Quantum Theory, Periodicity and Chemical Bonding. Chapter 10: Chemical Bonding II Molecular Geometry & Intermolecular Forces

Unit 3: Quantum Theory, Periodicity and Chemical Bonding. Chapter 10: Chemical Bonding II Molecular Geometry & Intermolecular Forces onour Chemistry Unit 3: Quantum Theory, Periodicity and Chemical Bonding Chapter 10: Chemical Bonding II Molecular Geometry & Intermolecular orces 10.1: Molecular Geometry Molecular Structure: - the three-dimensional

More information

Section Activity #1: Fill out the following table for biology s most common elements assuming that each atom is neutrally charged.

Section Activity #1: Fill out the following table for biology s most common elements assuming that each atom is neutrally charged. LS1a Fall 2014 Section Week #1 I. Valence Electrons and Bonding The number of valence (outer shell) electrons in an atom determines how many bonds it can form. Knowing the number of valence electrons present

More information

Exam 2 Chemistry 65 Summer 2015. Score:

Exam 2 Chemistry 65 Summer 2015. Score: Name: Exam 2 Chemistry 65 Summer 2015 Score: Instructions: Clearly circle the one best answer 1. Valence electrons are electrons located A) in the outermost energy level of an atom. B) in the nucleus of

More information

3. What would you predict for the intensity and binding energy for the 3p orbital for that of sulfur?

3. What would you predict for the intensity and binding energy for the 3p orbital for that of sulfur? PSI AP Chemistry Periodic Trends MC Review Name Periodic Law and the Quantum Model Use the PES spectrum of Phosphorus below to answer questions 1-3. 1. Which peak corresponds to the 1s orbital? (A) 1.06

More information

1.2 CLASSICAL THEORIES OF CHEMICAL BONDING

1.2 CLASSICAL THEORIES OF CHEMICAL BONDING 1. CLASSICAL TEORIES OF CEMICAL BONDING simply memorizing them. We ll consider some of the organic chemistry that is industrially important. Finally, we ll examine some of the beautiful applications of

More information

19.1 Bonding and Molecules

19.1 Bonding and Molecules Most of the matter around you and inside of you is in the form of compounds. For example, your body is about 80 percent water. You learned in the last unit that water, H 2 O, is made up of hydrogen and

More information