# Documents about Lewis Structure

• 2 Pages

#### lecture 2

University of Texas, CH 318M

Excerpt: ... nfiguration of sodium cation is 1s22s2sp6, which is neon-like. The electronic configuration of fluoride anion is also 1s22s2sp6, which is neon-like. Thus, formation of our product is driven by the ability to achieve a filled electronic shell. In general, to assess reactivity only the valence electrons need be considered, i.e. you can ignore inner shell electrons. To draw the Lewis structure of an atom, ignore the inner shell electrons. Just draw the atomic symbol and depict the valence electrons as dots. Using this protocol, we drew Lewis structure s for H2, F2 and HF. Note that bonding pairs of electrons are depicted as lines. Having drawn Lewis structure s for H2, F2 and HF, we briefly reviewed the concept of bond polarity and dipole moment. Know the trends in electronegativity (and why) and be able to use this knowledge to predict bond dipoles and identify ionic bonds, pure covalent bonds and polar covalent bonds. Rules for drawing Lewis structure s of more complex molecules. The ...

• 5 Pages

#### In class notes for September 10, 2007

Vanderbilt, CHEM 102a

Excerpt: ... General Chemistry Lecture 102a In class notes for September 10, 2007 Chapter 3 OWL due 9/16 at 11:59pm! Exam #1 is one week from Thursday! Last lecture Covalent bonding Lewis structure s/formal charges Today More Lewis structure s VSEPR Remember General rules of Lewis structure s Add up the total number of valence electrons available (A) Calculate number of electrons present if each atom has an octet (N) Exception is H, only needs two Subtract N from A . This is the number of shared electrons (S). The number of bonds is S/2 [S=F-A] Draw at least one bond (2 shared electrons) between atoms If any shared electrons remain, draw double or triple bonds until the number of bonds = s/2 Add electrons remaining electrons to atoms to give octet to each atom. The number of electrons should equal A Determine the formal charge on each atom. The sum of the formal charges should equal the total charge of the molecule. Examples of Lewis structure s ...

• 2 Pages

#### Lecture_2

University of Texas, CH 318m

Excerpt: ... nfiguration of sodium cation is 1s22s2sp6, which is neon-like. The electronic configuration of fluoride anion is also 1s22s2sp6, which is neon-like. Thus, formation of our product is driven by the ability to achieve a filled electronic shell. In general, to assess reactivity only the valence electrons need be considered, i.e. you can ignore inner shell electrons. To draw the Lewis structure of an atom, ignore the inner shell electrons. Just draw the atomic symbol and depict the valence electrons as dots. Using this protocol, we drew Lewis structure s for H2, F2 and HF. Note that bonding pairs of electrons are depicted as lines. Having drawn Lewis structure s for H2, F2 and HF, we briefly reviewed the concept of bond polarity and dipole moment. Know the trends in electronegativity (and why) and be able to use this knowledge to predict bond dipoles and identify ionic bonds, pure covalent bonds and polar covalent bonds. Rules for drawing Lewis structure s of more complex molecules. The ...

• 3 Pages

#### Lec-13-Chap-08-1P

SUNY Stony Brook, CHE 131

Excerpt: ... Lecture 13 Covalent Bonding Covalent Bonding 8.1 Single Bonds and Lewis Structure s 8.2 Single Covalent Bonds in Hydrocarbons 8.3 Multiple Covalent Bonds 8.4 Covalent Bonding sharing of electrons between atoms H:H H. + H. Lewis recognized that atoms share electrons when they form bonds with each other. H . H H H Lecture 13, Knowledge and Skills Understand the concept of the covalent bond Draw Lewis structure s of molecules with single and multiple bonds Hydrocarbons and other molecules with single bonds Functional groups in organic compounds Octet Rule: In chemical bond formation an atom gains or loses electrons, or shares pairs of electrons, until its valence shell has eight electrons. This rule holds for most main group elements. For hydrogen the number of electrons is two. Lewis Symbols Sulfur: element symbol S Group 16 6 valence electrons Paired electrons Unpaired electron Molecules with Single Bonds Number Group of valence number electrons 14 15 4 5 Number of electrons shared to ...

• 1 Pages

#### 8_Problems

Michigan State University, CEM 181

Excerpt: ... Chemistry 181H Problem Set #8, 25 October 2005 and 27 October 2005 1. (Problem 9 from Problem Set #7) Write Lewis structure s for NCO- and CNO-. Compare the shapes and dipole moments of these molecules with those of the isoelectronic molecule CO2. Sketch the shapes expected for each molecule, and indicate the direction of the dipole moment. 2. For Problem Set #7, you wrote Lewis structure s for BF3, NO3-, and NF3 and then applied VSEPR theory to predict molecular shapes and bond angles. Use these results to predict the magnitude (zero or nonzero) and direction of the dipole moments for these molecules. 3. Write Lewis structure s for XeF4, SbF5, XeO4, and XeOF2. Identify and sketch the shapes predicted for these molecules using VSEPR theory. Include bond angles on the sketch. Which of these molecules are polar? Show the direction of the dipole moment on the sketches of the polar molecules. 4. Draw Lewis structure (s) for the ozone molecule O3, and then use VSEPR to predict its molecular shape. 5. Consider the reac ...

• 2 Pages

#### chem 141 F07 Chapter 10 Study Sheet

Emory, CHEM 141

Excerpt: ... Please refer to the General Study Sheet Post for information regarding the exams CHAPTER 10 THE SHAPE OF MOLECULES We now have general models to describe the bonding in most chemical compounds. It is of paramount importance, however, to be able to predict the 3dimensional shape of molecules to understand their reactivity. This is done by first learning to represent molecules using Lewis structure s which give us information about the connectivity of the atoms in a molecules and the distribution of the valence and bonding electrons. We have developed the ability to draw virtually any molecule using Lewis structure s and to be able to determine which Lewis structure is the best through formal charges. In addition, we have been introduced to the concepts of resonance and resonance hybrids. Also, we can use Lewis structure s to calculate reaction enthalpies. From Lewis structure s we can uses the principles of Valence Shell Electron Pair Repulsion (VSEPR) theory to predict the 3-D shape of these molecules. We ...

• 6 Pages

#### Lecture_21

Sveriges lantbruksuniversitet, C 120

Excerpt: ... Todays Lecture Bonding: General Concepts 13.10 Lewis Structure s 13.11 Resonance 13.12 Exceptions to the Octet Rule 1 More Lewis Structure s Lewis structure of NH3 Lewis structure of NO+ 2 1 1 Resonance sometimes more than one Lewis structure is possible for a given molecule or polyatomic ion (i.e. two or more equivalent Lewis structure s - equivalent Lewis structure s contain the same numbers of single and multiple b d ) i h b f i l d l i l bonds) e.g. SO2 O S O O S O two possible resonance structures for SO2 based on either of the structures above, there should be two types of S-O bonds in the molecule: one shorter bond (i.e. the double bond) one longer bond (i.e. the single bond) note the double bond would be stronger than the single bond 3 Resonance (contd) experiments show that in SO2 the S-O bonds are equivalent (i.e. the S-O bond distance is the same for both S-O bonds) with a length and strength between that of a single and d bl b d f i l d double bond with that knowledge, ...

• 9 Pages

#### CA02

Washington, ANDREI 2

Excerpt: ... ChemActivity 2: Lewis Structure s (How do I draw a legitimate Lewis structure ?) Model 1: G. N. Lewis' Octet Rule In the early part of the last century, a chemist at the University of California at Berkeley named Gilbert N. Lewis devised a system for diagramming atoms and molecules. Though simple, the system is still used today because predictions made from these diagrams often match those based on experiment. Lewis proposed the following representations for the first ten elements with their valence electrons. H He Be B C N O F Ne Li Figure 2.1: Electron Dot Representations of Elements Only He and Ne are found in nature as shown above. All the other elements are found either as a charged species (ion) or as part of a molecule that can be represented as a legitimate Lewis structure . CHECKLIST: a Legitimate Lewis Structure is a dot or line bond representation in which. I. II. The correct TOTAL number of valence electrons is shown. The sum of the valence electrons around each hydrogen atom is two. III. The ...

• 7 Pages

#### Chapter 09

Saginaw Valley, CHEM 111

Excerpt: ... lent bond, we can designate a Lewis structure for the molecule, by accounting for the total number of electrons that each atom contributes Chem 111 lecture notes By Alan Zombeck page2 ffa26e2941ad9c48fc0c7fd394c7f44de467c4c3.doc Example hydrogen Covalent bonding and the octet rule When atoms form covalent bonds, they tend to share sufficient electrons so as to achieve an outer shell having eight electrons Examples HCl CH4 NH3 H2O Multiple bonds Sometimes more than one pair of electrons is shared between two atoms, when this happens a multiple bond is formed For example N2 Some important compounds of carbon (study from book) Methane Ethane Propane Ethylene Chem 111 lecture notes By Alan Zombeck page3 ffa26e2941ad9c48fc0c7fd394c7f44de467c4c3.doc Ethyl alcohol Electronegativity and the polarity of bonds In covalent bonds, we have a sharing of electrons. But what happens if one atom is "stronger" than the other, and wins the tug of war for the pair of electrons result is the creation o ...

• 3 Pages

#### ch 9 problem set2

Alabama, CH 101

Excerpt: ... Ch 9 - problem set #2 (due Tuesday, November 28) name:_ Practice writing Lewis Structure s for Covalent Compounds (CH101.004) 1. Write the Lewis structure of SF4 (sulfur tetrafluoride). 2. Write the Lewis structure of perchlorate anion (ClO4 ) (note: all Cl,O bonds are the same length). - 3. Write the Lewis structure for the radical C2H5 (ethyl radical). 4. Fill in the atom formal charges missing in the structures below. Note: all valence electrons are shown and the molecules may be charged or neutral. Also note that the C-H bonds have not been written out in order to simplify the molecular structure drawings. H2 C H2 C HC CH O CCNN H HC CH H3C CH2 H3C CH2 O H3C CH2 N C H3C CH3 H2 CH3 5. Write a Lewis structure for carbon monoxide, CO. There are two resonance structures, one with formal charges on the atom and one without. 6. Write the Lewis structure for methyl isocyanate, CH3NCO (bonded in that order). 7. Write Lewis structure s for 4 isomers with the formula C3H6O. How ma ...

• 1 Pages

#### 538.F04.16_note

Kentucky, CHE 538

Excerpt: ... Lecture 16 note. We opened the class with questions about exam 1 material. This went on longer than I anticipated. I felt hurried in lecture 16. When I was calculating the bond order for the allyl cation an internal check in my brain said, "hey hang on, why should the bond order be greater than ?" The Lewis structure predicts a pi-bond order of ! Right? Shouldn't the C1C2 pi bond order of the allyl cation be an average of these two equivalent weighted structures? H H 3 C C H 1 C2 H H pi C1C2 bond order=0 H H 3 C C H 1 C2 H H pi C1C2 bond order=1 It doesn't take much thinking to arrive at an explanation of why the bond order should be GREATER than 0.5. The effect is conjugation. The increased bond order is a direct result of the larger coefficient at C2. Here is a distinct advantage of Hckel theory over Lewis structure s. Estimating the rotational barrier for the allyl cation with Lewis structure s would have lead to an underestimation. What we gain in the bonding orbital in terms of bonding, we loose in ...

• 3 Pages

#### Ch3Worksheet3

UMass (Amherst), CHEM 121

Excerpt: ... Chapter 3 Lecture Worksheet 3 A. Define the term: homonuclear diatomic molecule. Give an example _ B. Give an example of a heteronuclear diatomic molecule. _ C. B2 has _ unpaired electrons. (Be sure that you can sketch the correlation diagram and label the y-axis and the atomic and molecular orbitals.) D. The bond order for B2 is _ PRS Answers: 0 = 0, 1 = 1, 2 = 2, 3 = 3, 4 = , 5 = 1 , 6 = 2 E. You would expect the bond in B2 to be 1. Stronger 2. Weaker F. Write the complete electron configuration for B2 . than the bond in B2 . G. Using MO theory you would predict C2 to be 1. Paramagnetic 2. Diamagnetic. H. Draw Lewis structure s for N2 and O2 I. Based on your Lewis structure s you would predict O2 to be 1. Paramagnetic 2. Diamagnetic. J. Sketch the correlation diagram for N2. K. Sketch the correlation diagram for O2. Note: For oxygen to neon 2p < 2p L. Based on MO Theory you would predict O2 to be 1. Paramagnetic 2. Diamagnetic ...

• 3 Pages

#### Ch16Worksheet1

UMass (Amherst), CHEM 121

Excerpt: ... Chapter 16 Lecture Worksheet 1 A. Define the term: homonuclear diatomic molecule. Give an example _ B. Give an example of a heteronuclear diatomic molecule. _ C. B2 has _ unpaired electrons. (Be sure that you can sketch the correlation diagram and label the y-axis and the atomic and molecular orbitals.) D. The bond order for B2 is _ PRS Answers: 0 = 0, 1 = 1, 2 = 2, 3 = 3, 4 = , 5 = 1 , 6 = 2 E. You would expect the bond in B2 to be 1. Stronger 2. Weaker F. Write the complete electron configuration for B2 . than the bond in B2 . G. Using MO theory you would predict C2 to be 1. Paramagnetic 2. Diamagnetic. H. Draw Lewis structure s for N2 and O2 I. Based on your Lewis structure s you would predict O2 to be 1. Paramagnetic 2. Diamagnetic. J. Sketch the correlation diagram for N2. K. Sketch the correlation diagram for O2. Note: For oxygen to neon 2p < 2p L. Based on MO Theory you would predict O2 to be 1. Paramagnetic 2. Diamagnetic. M. The ...

• 1 Pages

#### StudyGuide1-3

UPenn, CHEM 243

Excerpt: ... Chemistry 243 Study Guide Lectures 1-3 Reading Textbook: Chapter 1 Optional: Acid/Base Chemistry Tutorial (highly recommended) Topics Lewis structure of molecules VESPR Covalent and ionic bonds Molecular bonding and antibonding orbitals Hybrid atomic orbitals orbitals Polar bonds Acid/Base chemistry Definitions Know the following terms. Lewis structure , Kekul structure, covalent bonds, electronegativity, ionic bond, and bonds, hybrid atomic orbitals, Brnsted acids and bases, Lewis acids and bases. Skills to Master Be able to determine the reasonable Lewis structure s of a molecule from a molecular formula. Be able to estimate the bonding and antibonding orbitals in simple carbon compounds. Be able to identify non-polar and polar covalent bonds in a molecule. Be able to estimate the relative strengths of acids by inspecting the structure of a molecule. Be able to calculate the concentrations of acids and bases in an acid/base equilibrium reaction. Textbook problems I recommend that you att ...

• 1 Pages

#### Chem 1100 Exam 1 study guide

Missouri (Mizzou), CHEM 1100

Excerpt: ... Chem 1100 Exam #1 Study Guide NOTE: This document is not intended to be a comprehensive list of all material appearing on the exam. It is a general guide outlining what I perceive as the topics most emphasized. ANYTHING from the sections covered in lecture and emphasized in lab are FAIR GAME for the exam! Radiation: Conversions between frequency, energy, and wavelength Molecules: Lewis structure s (you will be expected to draw them!) Octet rule Free radicals Three-dimensional shapes (drawing and naming!) Moles Like a dozen (or a pair), except 6.022 x 1023 instead of 12 (or 2) Balanced chemical equations Conservation of mass/stoichiometry Atoms and Elements Periodic table Atomic structure (protons, neutrons, electrons) Isotopes (including notation) Allotropes Interactions between light and matter Absorbing energies depending on structure, strength of bonds Breaking bonds (esp. in relation to ozone) Molecular vibrations (esp. relating to the greenhouse effect) How ozone protects from UV radiation Catalysis Chapm ...

• 4 Pages

#### Lec-13-Chap-08-1

SUNY Stony Brook, CHE 131

Excerpt: ... Lecture 13, Knowledge and Skills Lecture 13 Covalent Bonding Covalent Bonding 8.1 Single Bonds and Lewis Structure s 8.2 Single Covalent Bonds in Hydrocarbons 8.3 Multiple Covalent Bonds 8.4 Understand the concept of the covalent bond Draw Lewis structure s of molecules with single and multiple bonds Hydrocarbons and other molecules with single bonds Functional groups in organic compounds Covalent Bonding Atomic Interactions sharing of electrons between atoms H. + H. H:H Lewis recognized that atoms share electrons when they form bonds with each other. Octet Rule In chemical bond formation an atom gains or loses electrons, or shares pairs of electrons, until its valence shell has eight electrons. This rule holds for most main group elements. For hydrogen the number of electrons is two. H . H H H Each of the hydrogen atoms can claim to possess an electron pair, to have a filled valence shell! 1 Lewis Symbols Sulfur: element symbol S Group 16 6 valence elect ...

• 5 Pages

#### ch10_key

Cal Poly, CHEM 127

Excerpt: ... Chapter 10 Worksheet Key 2. NOTE: for exam 2, you should be able to draw the Lewis Structure , but that is it, you don't need to know the other parts (the VSEPR sketch, geometry, etc.) 3. ...

• 2 Pages

#### Lewis Structures

Chattanooga State, CHEM 1010

Excerpt: ... I. Lewis Structure s of Covalent Molecules a. A covalent bond is a shared pair of electrons i. Hydrogen ii. Fluorine iii. Hydrogen fluoride iv. Chlorite ion see worksheet b. Counting valence electrons i. See class notes Lewis Structure c. Multiple Bonds i. Double bond 1. Two pairs of electrons shared between 2 atoms a. Ex. oxygen ii. Resonance structure iii. Triple bond 1. Three pairs of electrons shared between two atoms a. Ex. nitrogen II. Light (Electromagnetic Radiation) a. Behaves something like a wave b. Wavelength ( ) i. The distance between successive peaks on a wave ii. See notes Lewis Structure (Wavelength) c. Frequency ( ) i. The number of waves passing a fixed point in one second ii. Hertz 1. Unit used to measure frequency 2. 1 cycle/sec (1/sec or sec-1) iii. High frequency 1. High energy 2. Short wavelength iv. Low frequency 1. Low energy 2. Long wavelength d. The speed of light i. C = ii. C = 3.00 x 108 m/s iii. See notes Lewis Structure (Speed of Light) ...

• 40 Pages

#### Chem 141 F06 Chapter 10

Emory, CHEM 141

Excerpt: ... SI Questions for Chapter 10 Sections 000 and 004 Write the major Lewis structure (s) for the following molecules. Include any formal charges and resonance structures. If resonance is possible, determine the major resonance structure. H2CN2 (2 skeletal arrangements + resonance) C6H6 (note: contains a ring of C atoms) SCN- (3 resonance structures) H3PO4 ClO2- (2 skeletal structures) Compare the Lewis structure s of CNO- and OCN-. Which one of these compounds is unstable and makes explosive materials? (note that each structure had three resonance structures) ...

• 5 Pages

#### PS.LewisStructures-3.A

Youngstown, CHEM 1501

Excerpt: ... Lewis Structure s - 3rd Problem Set Answers ...