Electronegativity. Tip: Element Electronegativity Element Electronegativity. Hydrogen (H) 2,1. Lithium (Li) 1,0. Beryllium (Be) 1,5.

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "Electronegativity. Tip: Element Electronegativity Element Electronegativity. Hydrogen (H) 2,1. Lithium (Li) 1,0. Beryllium (Be) 1,5."

Transcription

1 Electronegativity So far we have looked at covalent molecules. But how do we know that they are covalent? The answer comes from electronegativity. Each element (except for the noble gases) has an electronegativity value. Electronegativity is a measure of how strongly an atom pulls a shared electron pair towards it. The table below shows the electronegativities of the some of the elements. For a full list of electronegativities see the periodic table at the front of the book. On this periodic table the electronegativity values are given in the top right corner. Do not confuse these values with the other numbers shown for the elements. Electronegativities will always be between 0 and 4 for any element. If you use a number greater than 4 then you are not using the electronegativity. Tip: Depending on which source you use for electronegativities you may see slightly different values. Element Electronegativity Element Electronegativity Hydrogen (H) 2,1 Lithium (Li) 1,0 Beryllium (Be) 1,5 Boron (B) 2,0 Carbon (C) 2,5 Nitrogen (N) 3,0 Oxygen (O) 3,5 Fluorine (F) 4,0

2 Sodium (Na) 0,9 Magnesium (Mg) 1,2 Aluminium (Al) 1,5 Silicon (Si) 1,8 Phosphorous (P) 2,1 Sulfur (S) 2,5 Chlorine (Cl) 3,0 Potassium (K) 0,8 Calcium (Ca) 1,0 Bromine (Br) 2,8 Table 1: Table of electronegativities for selected elements. Definition 1: Electronegativity Electronegativity is a chemical property which describes the power of an atom to attract electrons towards itself. Interesting Fact: The concept of electronegativity was introduced by Linus Pauling in 1932, and this became very useful in explaining the nature of s between atoms in molecules. For this work, Pauling was awarded the Nobel Prize in Chemistry in He also received the Nobel Peace Prize in 1962 for his campaign against above-ground nuclear testing. The greater the electronegativity of an atom of an element, the stronger its attractive pull on electrons. For example, in a molecule of hydrogen bromide (HBr), the electronegativity of bromine (2,8) is higher than that of hydrogen (2,1), and so the shared electrons will spend more of their time closer to the bromine atom. Bromine will have a slightly negative charge, and hydrogen will have a slightly positive charge. In a molecule like hydrogen (H2) where

3 the electronegativities of the atoms in the molecule are the same, both atoms have a neutral charge. Example 1: Calculating electronegativity differences Question Calculate the electronegativity difference between hydrogen and oxygen. Answer Read the electronegativity of each element off the periodic table. From the periodic table we find that hydrogen has an electronegativity of 2,1 and oxygen has an electronegativity of 3,5. Calculate the electronegativity difference 3,5 2,1=1,4 Exercise 1: Problem 1: Calculate the electronegativity difference between: Be and C, H and C, Li and F, Al and Na, C and O. Practise more questions like this Answer 1: Be and C: 2,5 1,5=1,0. H and C: 2,5 2,1=0,4. Li and F: 4,0 1,0=3,0. Al and Na: 1,5 0,9=0,6. C and O: 3,5 2,5=1,0. Electronegativity and ing The electronegativity difference between two atoms can be used to determine what type of ing exists between the atoms. The table below lists the approximate values. Although we have given ranges here ing is more like a spectrum than a set of boxes.

4 Figure 1 Electronegativity difference Type of 0 Non-polar covalent 0-1 Weak polar covalent 1,1-2 Strong polar covalent > 2,1 Ionic Tip: Table 1 Note that metallic ing is not given here. Metals have low electronegativities and so the valence electrons are not drawn strongly to any one atom. Instead, the valence electrons are loosely shared by all the atoms in the metallic network. Non-polar and polar covalent s It is important to be able to determine if a molecule is polar or non-polar since the polarity of molecules affects properties such as solubility, melting points and boiling points. Electronegativity can be used to explain the difference between two types of covalent s. Non-polar covalent s occur between two identical non-metal atoms, e.g. H2, Cl2 and O2. Because the two atoms have the same electronegativity, the electron pair in the covalent is shared equally between them. However, if two different nonmetal atoms then the shared electron pair will be pulled more strongly by the atom with the higher electronegativity. As a result, a polar covalent is formed where one atom will have a slightly negative charge and the other a slightly positive charge.

5 This slightly positive or slightly negative charge is known as a partial charge. These partial charges are represented using the symbols δ+ (slightly positive) and δ (slightly negative). So, in a molecule such as hydrogen chloride (HCl), hydrogen is Hδ+ and chlorine is Clδ. Tip: The symbol δ is read as delta. Polar molecules Some molecules with polar covalent s are polar molecules, e.g. H2O. But not all molecules with polar covalent s are polar. An example is CO2. Although CO2 has two polar covalent s (between Cδ+ atom and the two Oδ atoms), the molecule itself is not polar. The reason is that CO2 is a linear molecule, with both terminal atoms the same, and is therefore symmetrical. So there is no difference in charge between the two ends of the molecule. Definition 2: Polar molecules A polar molecule is one that has one end with a slightly positive charge, and one end with a slightly negative charge. Examples include water, ammonia and hydrogen chloride. Definition 3: Non-polar molecules Tip: A non-polar molecule is one where the charge is equally spread across the molecule or a symmetrical molecule with polar s. Examples include carbon dioxide and oxygen. To determine if a molecule is symmetrical look first at the atoms around the central atom. If they are different then the molecule is not symmetrical. If they are the same then the molecule may be symmetrical and we need to look at the shape of the molecule. We can easily predict which molecules are likely to be polar and which are likely to be nonpolar by looking at the molecular shape. The following activity will help you determine this and will help you understand more about symmetry.

6 Activity 1: Polar and non-polar molecules The following table lists the molecular shapes. Build the molecule given for each case using jellytots and toothpicks. Determine if the shape is symmetrical. (Does it look the same whichever way you look at it?) Now decide if the molecule is polar or non-polar. Geometry Molecule Symmetrical Polar or non-polar Linear HCl Linear CO2 Linear HCN Bent or angular H2O Trigonal planar BF3 Trigonal planar BF2Cl Trigonal pyramidal NH3 Tetrahedral CH4

7 Tetrahedral CH3Cl Trigonal bipyramidal PCl5 Trigonal bipyramidal PCl4F Octahedral SF6 Octahedral SF5Cl Table 2 Click to Run Example 2: Polar and non-polar molecules Question State whether hydrogen (H2) is polar or non-polar. Answer

8 Determine the shape of the molecule The molecule is linear. There is one ing pair of electrons and no lone pairs. Write down the electronegativities of each atom Hydrogen: 2,1 Determine the electronegativity difference for each There is only one and the difference is 0. Determine the polarity of each The is non-polar. Determine the polarity of the molecule The molecule is non-polar. Example 3: Polar and non-polar molecules Question State whether methane (CH4) is polar or non-polar. Answer Determine the shape of each molecule The molecule is tetrahedral. There are four ing pairs of electrons and no lone pairs. Determine the electronegativity difference for each There are four s. Since each is between carbon and hydrogen, we only need to calculate one electronegativity difference. This is: 2,5 2,1=0,4 Determine the polarity of each Each is polar. Determine the polarity of the molecule The molecule is symmetrical and so is non-polar.

9 Example 4: Polar and non-polar molecules Question State whether hydrogen cyanide (HCN) is polar or non-polar. Answer Determine the shape of the molecule The molecule is linear. There are four ing pairs, three of which form a triple and so are counted as 1. There is one lone pair on the nitrogen atom. Determine the electronegativity difference and polarity for each There are two s. One between hydrogen and carbon and the other between carbon and nitrogen. The electronegativity difference between carbon and hydrogen is 0,4 and the electronegativity difference between carbon and nitrogen is 0,5. Both of the s are polar. Determine the polarity of the molecule The molecule is not symmetrical and so is polar. Exercise 2: Electronegativity Problem 1: In a molecule of beryllium chloride (BeCl2): 1. What is the electronegativity of beryllium? 2. What is the electronegativity of chlorine? 3. Which atom will have a slightly positive charge and which will have a slightly negative charge in the molecule? Represent this on a sketch of the molecule using partial charges. 4. Is the a non-polar or polar covalent? 5. Is the molecule polar or non-polar? Practise more questions like this Answer 1: 1. 2,1

10 2. 3,0 3. Hydrogen will have a slightly positive charge and chlorine will have a slightly negative charge. 4.. The electronegativity difference is: 3,0 2,1=0,9. The is weakly polar. 5. Hydrogen chloride is linear and therefore is a polar molecule. Problem 2: Complete the table below: Molecule Difference in Non-polar/polar Polar/non-polar electronegativity between covalent molecule atoms H2O HBr F2 CH4 PF5 BeCl2 CO C2H2 SO2 BF3

11 Table 3 Practise more questions like this Answer 2: Molecule Difference in Non- Polar/non-polar molecule electronegativity polar/polar between atoms covalent H2O 3,5 2,1=1,4 Polar molecule. Water has a bent or angular shape. HBr 2,8 2,1=0,7 Polar molecule. Hydrogen bromide is linear. F2 4,0 4,0=0 Non-polar Non-polar molecule. covalent CH4 2,5 2,1=0,4 Non-polar molecule. Methane is tetrahedral. PF5 4,0 2,1=1,9 Non-polar molecule. Phosphorous pentafluoride is trigonal bypramidal and symmetrical.

12 BeCl2 3,0 1,5=1,5 Non-polar molecule. Beryllium chloride is linear and symmetrical. CO 3,5 2,5=1,0 Polar molecule. Carbon monoxide is linear, but not symmetrical. C2H2 2,5 2,1=0,4 Non-polar molecule. Acetylene is linear and symmetrical. SO2 3,5 2,5=1,0 Polar molecule. Sulfur dioxide is bent or angular and is not symmetrical. BF3 4,0 2,0=2,0 Non-polar molecule. Boron trifluoride is trigonal pyramidal and not symmetrical. Table 4

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

Principal energy levels are divided into sublevels following a distinctive pattern, shown in Table 5.1 below.

Principal energy levels are divided into sublevels following a distinctive pattern, shown in Table 5.1 below. 56 Chapter 5: Electron Configuration, Lewis Dot Structure, and Molecular Shape Electron configuration. The outermost electrons surrounding an atom (the valence electrons) are responsible for the number

More information

Chapter 11. Chemical Bonds: The Formation of Compounds from Atoms

Chapter 11. Chemical Bonds: The Formation of Compounds from Atoms Chapter 11 Chemical Bonds: The Formation of Compounds from Atoms 1 11.1 Periodic Trends in atomic properties 11.1 Periodic Trends in atomic properties design of periodic table is based on observing properties

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

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

Chapter 9-10 practice test

Chapter 9-10 practice test Class: Date: Chapter 9-10 practice test Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Which one of the following is most likely to be an ionic compound?

More information

Copyright 2014 Edmentum - All rights reserved. Chemistry Chemical bonding, molecular structure and Gases Blizzard Bag 2014-2015

Copyright 2014 Edmentum - All rights reserved. Chemistry Chemical bonding, molecular structure and Gases Blizzard Bag 2014-2015 Copyright 2014 Edmentum - All rights reserved. Chemistry Chemical bonding, molecular structure and Gases Blizzard Bag 2014-2015 1. Which of the following is a unit of pressure? A. newton-meters per second

More information

Chapter 12 Review 1: Covalent Bonds and Molecular Structure

Chapter 12 Review 1: Covalent Bonds and Molecular Structure Chapter 12 Review 1: Covalent Bonds and Molecular Structure 1) How are ionic bonds and covalent bonds different, and what types of elements combine to form each? Ionic bonds result from the transfer of

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

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

Atomic Theory and Bonding

Atomic Theory and Bonding Atomic Theory and Bonding Textbook pages 168 183 Section 4.1 Summary Before You Read What do you already know about Bohr diagrams? Record your answer in the lines below. What are atoms? An atom is the

More information

Test 8: Review Questions

Test 8: Review Questions Name: Thursday, February 14, 2008 Test 8: Review Questions 1. Based on bond type, which compound has the highest melting point? 1. CH OH 3. CaCl 3 2 2. C H 4. CCl 6 14 4 2. Which compound contains ionic

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

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

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

Bonding Web Practice. Trupia

Bonding Web Practice. Trupia 1. If the electronegativity difference between the elements in compound NaX is 2.1, what is element X? bromine fluorine chlorine oxygen 2. Which bond has the greatest degree of ionic character? H Cl Cl

More information

EXPERIMENT 14: COMPARISONS OF THE SHAPES OF MOLECULES AND IONS USING MODELS

EXPERIMENT 14: COMPARISONS OF THE SHAPES OF MOLECULES AND IONS USING MODELS EXPERIMENT 14: CMPARISNS F TE SAPES F MLECULES AND INS USING MDELS PURPSE Models of various molecules and ions will be constructed and their shapes and geometries will be compared. BACKGRUND LEWIS STRUCTURES

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

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

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

Chapter 5 Chemical Compounds. An Introduction to Chemistry by Mark Bishop

Chapter 5 Chemical Compounds. An Introduction to Chemistry by Mark Bishop Chapter 5 Chemical Compounds An Introduction to Chemistry by Mark Bishop Chapter Map Elements, Compounds, and Mixtures Element: A substance that cannot be chemically converted into simpler substances;

More information

Packet 4: Bonding. Play song: (One of Mrs. Stampfel s favorite songs)

Packet 4: Bonding. Play song:  (One of Mrs. Stampfel s favorite songs) Most atoms are not Packet 4: Bonding Atoms will, or share electrons in order to achieve a stable. Octet means that the atom has in its level. If an atom achieves a stable octet it will have the same electron

More information

3.4 Covalent Bonds and Lewis Structures

3.4 Covalent Bonds and Lewis Structures 3.4 Covalent Bonds and Lewis Structures The Lewis Model of Chemical Bonding In 1916 G. N. Lewis proposed that atoms combine in order to achieve a more stable electron configuration. Maximum stability results

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

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

Chemical bonds between atoms involve electrons.

Chemical bonds between atoms involve electrons. Chapter 6, Section 2 Key Concept: Chemical bonds hold compounds together. BEFORE, you learned Elements combine to form compounds Electrons are located in a cloud around the nucleus Atoms can lose or gain

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

Name: Intermolecular Forces Practice Exam Date:

Name: Intermolecular Forces Practice Exam Date: Name: Intermolecular Forces Practice Exam Date: 1. At STP, fluorine is a gas and bromine is a liquid because, compared to fluorine, bromine has 1) stronger covalent bonds 2) stronger intermolecular forces

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

3/5/2014. iclicker Participation Question: A. MgS < AlP < NaCl B. MgS < NaCl < AlP C. NaCl < AlP < MgS D. NaCl < MgS < AlP

3/5/2014. iclicker Participation Question: A. MgS < AlP < NaCl B. MgS < NaCl < AlP C. NaCl < AlP < MgS D. NaCl < MgS < AlP Today: Ionic Bonding vs. Covalent Bonding Strengths of Covalent Bonds: Bond Energy Diagrams Bond Polarities: Nonpolar Covalent vs. Polar Covalent vs. Ionic Electronegativity Differences Dipole Moments

More information

Lab Manual Supplement

Lab Manual Supplement Objectives 1. Learn about the structures of covalent compounds and polyatomic ions. 2. Draw Lewis structures based on valence electrons and the octet rule. 3. Construct 3-dimensional models of molecules

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

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

Unit 28 Molecular Geometry

Unit 28 Molecular Geometry Unit 28 Molecular Geometry There are two concepts in the study of molecular geometry. One is called the Valence Shell Electron Pair Repulsion (VSEPR) model. The other is electron orbital hybridization.

More information

Lewis Dot Formulas of Atoms

Lewis Dot Formulas of Atoms Lewis Dot Formulas of Atoms Lewis dot formulas or Lewis dot representations are a convenient bookkeeping method for tracking valence electrons. Valence electrons are those electrons that are transferred

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

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 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

EXAM 4 CH (Blackstock) November 30, 2006

EXAM 4 CH (Blackstock) November 30, 2006 EXAM 4 CH101.004 (Blackstock) November 30, 2006 Student name (print): honor pledge: 1. Which of these choices is the general electron configuration for the outermost electrons of elements in the alkaline

More information

Chapter 6 Assessment. Name: Class: Date: ID: A. Multiple Choice Identify the choice that best completes the statement or answers the question.

Chapter 6 Assessment. Name: Class: Date: ID: A. Multiple Choice Identify the choice that best completes the statement or answers the question. Name: Class: Date: ID: A Chapter 6 Assessment Multiple Choice Identify the choice that best completes the statement or answers the question. 1. When an atom loses an electron, it forms a(n) a. anion. c.

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

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

Chemical Bonds. Chemistry 100. Bettelheim, Brown, Campbell & Farrell. Introduction to General, Organic and Biochemistry Chapter 3

Chemical Bonds. Chemistry 100. Bettelheim, Brown, Campbell & Farrell. Introduction to General, Organic and Biochemistry Chapter 3 hemistry 100 Bettelheim, Brown, ampbell & arrell Ninth Edition Introduction to General, rganic and Biochemistry hapter 3 hemical Bonds Electronic Structure & hemical Valence An atom that loses one or more

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

UNIT TEST Atomic & Molecular Structure. Name: Date:

UNIT TEST Atomic & Molecular Structure. Name: Date: SCH4U UNIT TEST Atomic & Molecular Structure Name: _ Date: Part A - Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. 1. Who postulated that electrons

More information

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

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

More information

Lewis Dot Structure of Hydrogen Fluoride.

Lewis Dot Structure of Hydrogen Fluoride. Lewis Dot Structure of Hydrogen Fluoride. Drawing Lewis Structures Sum the valence electrons from all atoms in the species. Write the atomic symbols for the atoms involved so as to show which atoms are

More information

Solid Type of solid Type of particle

Solid Type of solid Type of particle QUESTION (2015:3) Complete the table below by stating the type of solid, the type of particle, and the attractive forces between the particles in each solid. Solid Type of solid Type of particle Cu(s)

More information

Lewis Dot Structure Answer Key

Lewis Dot Structure Answer Key Lewis Dot Structure Answer Key 1) Nitrogen is the central atom in each of the following species: N2 N2 - N2 + Nitrogen can also form electron deficient compounds with a single unpaired electron on the

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

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

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

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

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

Sharing of Electrons. Covalent Bonding Chapter 8. Ch. 8 Vocabulary OBJECTIVES. Exothermic Reaction Structural Formula (Ch. 8.3) Polar Covalent Bond

Sharing of Electrons. Covalent Bonding Chapter 8. Ch. 8 Vocabulary OBJECTIVES. Exothermic Reaction Structural Formula (Ch. 8.3) Polar Covalent Bond Ch. 8 Vocabulary 2 Covalent Bonding Chapter 8 Covalent bond Molecule Lewis Structure Sigma bond Pi bond Bond Dissociation Energy Endothermic Reaction Exothermic Reaction Structural Formula (Ch. 8.3) Polar

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

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

Chapter 18: How Atoms Bond and Molecules Attract. 18.1: Electron-Dot Structures Help Us to Understand Bonding

Chapter 18: How Atoms Bond and Molecules Attract. 18.1: Electron-Dot Structures Help Us to Understand Bonding Chapter 18: How Atoms Bond and Molecules Attract Name: 18.1: Electron-Dot Structures Help Us to Understand Bonding What are the 3 types of bonds we will be learning about? When 2 atoms meet, which part

More information

CHAPTER NOTES CHAPTER 16. Covalent Bonding

CHAPTER NOTES CHAPTER 16. Covalent Bonding CHAPTER NOTES CHAPTER 16 Covalent Bonding Goals : To gain an understanding of : NOTES: 1. Valence electron and electron dot notation. 2. Stable electron configurations. 3. Covalent bonding. 4. Polarity

More information

Unit 8: Drawing Molecules

Unit 8: Drawing Molecules Unit 8: Drawing Molecules bjectives Topic 1: Lewis Dot Diagrams & Ionic Bonding 1. Draw a Lewis dot diagram of any representative element. 2. Draw a Lewis dot diagram of any ionic compound. A Lewis structure

More information

Covalent Bonding And Molecular Geometry

Covalent Bonding And Molecular Geometry ovalent Bonding And Molecular Geometry Questions: 1.ow can the valence electrons of an atom be represented? 2.ow do atoms achieve an octet? 3.ow are electrons shared in a molecule? 4.ow can the geometries

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

Lesmahagow High School CfE Higher Chemistry. Chemical Changes & Structure Structure and Bonding

Lesmahagow High School CfE Higher Chemistry. Chemical Changes & Structure Structure and Bonding Lesmahagow High School CfE Higher Chemistry Chemical Changes & Structure Structure and Bonding Page 1 of 26 No. Learning Outcome Understanding? 1 2 The bonding types of the first twenty elements; metallic

More information

Periodic Table Study Guide

Periodic Table Study Guide Chemistry Periodic Table Name: Period: 1 2 3 4 5 6 7 8 Periodic Table Study Guide Directions: Please use this packet as practice and review. DO NOT try to answer these questions during presentations, take

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

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

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

What Are the Shapes of Molecules?

What Are the Shapes of Molecules? Lab 7 Name What Are the Shapes of Molecules? Pre-Lab Assignment Read the entire lab handout. There is no written pre-lab assignment for this lab. Learning Goals Derive the Lewis structure of a covalent

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

Chapter 11: Chemical Bonds: The Formation of Compounds from Atoms

Chapter 11: Chemical Bonds: The Formation of Compounds from Atoms Chapter 11: Chemical Bonds: The Formation of Compounds from Atoms Name: Many of the concepts in this chapter come from the idea that elements are always trying to obtain 8 valence electrons because this

More information

Chapter 4 Compounds and Their Bonds

Chapter 4 Compounds and Their Bonds Chapter 4 Compounds and Their Bonds 4.1 Octet Rule and Ions Octet Rule An octet is 8 valence electrons. is associated with the stability of the noble gases. He is stable with 2 valence electrons (duet).

More information

Assessment Schedule 2015 Chemistry: Demonstrate understanding of bonding, structure, properties and energy changes (91164)

Assessment Schedule 2015 Chemistry: Demonstrate understanding of bonding, structure, properties and energy changes (91164) NCEA Level 2 Chemistry (91164) 2015 page 1 of 7 Assessment Schedule 2015 Chemistry: Demonstrate understanding of bonding, structure, properties and energy changes (91164) Evidence Statement Q Evidence

More information

COVALENT BONDING. [MH5; Chapter 7]

COVALENT BONDING. [MH5; Chapter 7] COVALENT BONDING [MH5; Chapter 7] Covalent bonds occur when electrons are equally shared between two atoms. The electrons are not always equally shared by both atoms; these bonds are said to be polar covalent.

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

S block elements p block elements and chemical bonding -1

S block elements p block elements and chemical bonding -1 S block elements p block elements and chemical bonding -1 1.Group I elements do not occur free (native state) in the nature because a. They are unstable b. Their compounds with other elements are highly

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

Unit 3 Study Guide: Electron Configuration & The Periodic Table

Unit 3 Study Guide: Electron Configuration & The Periodic Table Name: Teacher s Name: Class: Block: Date: Unit 3 Study Guide: Electron Configuration & The Periodic Table 1. For each of the following elements, state whether the element is radioactive, synthetic or both.

More information

Molecular Models: Lewis Structure and VSEPR Theory

Molecular Models: Lewis Structure and VSEPR Theory Minneapolis Community & Technical College Chemistry Department Chem 1020 Laboratory Molecular Models: Lewis Structure and VSEPR Theory bjectives To determine the Lewis structure for a molecule To determine

More information

Name: Block: Date: Test Review: Chapter 8 Ionic Bonding

Name: Block: Date: Test Review: Chapter 8 Ionic Bonding Name: Block: Date: Test Review: Chapter 8 Ionic Bonding Part 1: Fill-in-the-blank. Choose the word from the word bank below. Each word may be used only 1 time. electron dot structure metallic electronegativity

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

Chapter 5 Chemical Compounds

Chapter 5 Chemical Compounds Chapter 5 59 Chapter 5 Chemical Compounds Review Skills 5.1 Classification of Matter 5.2 Compounds and Chemical Bonds Equal and Unequal Sharing of Electrons Transfer of Electrons Summary of Covalent and

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

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

TRENDS IN THE PERIODIC TABLE

TRENDS IN THE PERIODIC TABLE Noble gases Period alogens Alkaline earth metals Alkali metals TRENDS IN TE PERIDI TABLE Usual charge +1 + +3-3 - -1 Number of Valence e - s 1 3 4 5 6 7 Electron dot diagram X X X X X X X X X 8 Group 1

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

5. Which of the following subatomic particles are most important in determining the chemical reactivity and physical properties of an atom?

5. Which of the following subatomic particles are most important in determining the chemical reactivity and physical properties of an atom? 1. For the following compounds draw the Lewis Structure and determine: (a) The # of Bonding Pairs (b) The # of Lone pairs (c) The electron domain shape (d) The molecular shape (e) Hybridization (f) Whether

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

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

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

Period 3 elements

Period 3 elements 3.1.4.2 Period 3 elements 173 minutes 169 marks Page 1 of 17 Q1. (a) Explain why certain elements in the Periodic Table are classified as p-block elements. Illustrate your answer with an example of a p-block

More information

WRITING CHEMICAL FORMULA

WRITING CHEMICAL FORMULA WRITING CHEMICAL FORMULA For ionic compounds, the chemical formula must be worked out. You will no longer have the list of ions in the exam (like at GCSE). Instead you must learn some and work out others.

More information

Inorganic Chemistry with Doc M. Day 3. Covalent bonding: Lewis dot structures and Molecular Shape.

Inorganic Chemistry with Doc M. Day 3. Covalent bonding: Lewis dot structures and Molecular Shape. Inorganic Chemistry with Doc M. Day 3. Covalent bonding: Lewis dot structures and Molecular Shape. Topics: 1. Covalent bonding, Lewis dot structures in review, formal charges 2. VSEPR 6. Resonance 3. Expanded

More information

EXPERIMENT # 17 CHEMICAL BONDING AND MOLECULAR POLARITY

EXPERIMENT # 17 CHEMICAL BONDING AND MOLECULAR POLARITY EXPERIMENT # 17 CHEMICAL BONDING AND MOLECULAR POLARITY Purpose: 1. To distinguish between different types of chemical bonds. 2. To predict the polarity of some common molecules from a knowledge of bond

More information

Chapter 6: The Periodic Table Study Guide

Chapter 6: The Periodic Table Study Guide Chapter 6: The Periodic Table Study Guide I. General organization of table A. Modern periodic table 1. Increasing atomic number B. 3 major blocks 1. Metals a. Mostly solids at room temperature b. Conduct

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

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

2.1. The Formation of Ionic and Covalent Bonds. Clues in Naturally Occurring Compounds SECTION. Key Terms

2.1. The Formation of Ionic and Covalent Bonds. Clues in Naturally Occurring Compounds SECTION. Key Terms SETI 2.1 The Formation of Ionic and ovalent Bonds Key Terms octet rule ionic bond ionic compound covalent bond molecular compound single bond double bond triple bond bonding pair lone pair Lewis structure

More information

Question Bank Periodic Table and Periodic Properties

Question Bank Periodic Table and Periodic Properties Question Bank Periodic Table and Periodic Properties 1. Name the following with reference to the elements of Modern Periodic Table. (1 26) (a) An alkali metal in period 2. Ans. Lithium (b) A halogen in

More information

Name. Worksheet: Periodic Trends. 11. Which sequence of elements is arranged in order of decreasing atomic radii?

Name. Worksheet: Periodic Trends. 11. Which sequence of elements is arranged in order of decreasing atomic radii? 1. Which statement best describes Group 2 elements as they are considered in order from top to bottom of the Periodic Table? (A) The number of principal energy levels increases, and the number of valence

More information

The Periodic Table: Periodic trends

The Periodic Table: Periodic trends Unit 1 The Periodic Table: Periodic trends There are over one hundred different chemical elements. Some of these elements are familiar to you such as hydrogen, oxygen, nitrogen and carbon. Each one has

More information