CHEM101 Lecture 15: February 8: Review, Lewis Dot Structures, Resonance Structures,Picking the Best Resonance Structures (continued), Molecular Shape and Structure (not on first midterm), Electron Group Arrangements and Molecular Shapes, VSEPR Guidelines

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khurley

9 Feb 2019

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University of Alberta

Department

Chemistry

Course

CHEM101

Professor

Rylan Lundgren

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CHEM101 Lecture 14: February 6: Breaking the Octet Rule (continued), Formal Atom Charges, Resonance Structures, Electron Delocalization, Picking the Best Resonance Structures.

CHEM101 Lecture 15: February 8: Review, Lewis Dot Structures, Resonance Structures,Picking the Best Resonance Structures (continued), Molecular Shape and Structure (not on first midterm), Electron Group Arrangements and Molecular Shapes, VSEPR Guidelines

CHEM101 Lecture 16: February 11: Electron Group Arrangements and Molecular Shapes: two electron groups,

Document Summary

February 8: review, lewis dot structures, resonance structures,picking the best. Resonance structures (continued), molecular shape and structure (not on first midterm), Electron group arrangements and molecular shapes, vsepr guidelines. The least electronegative element is used as the central atom. Elements in periods 1 and 2 prefer to have full octets, the double bond creates a full octet for both the oxygen and carbon element. The only difference between the two structures is where the double bond is placed. The arrow between the two structures is referred to as a resonance arrow. The hybrid structure splits the double bond between the two oxygen atoms, giving each oxygen a - charge. This diagram represents a hybrid resonance structure. https://d2jmvrsizmvf4x. cloudfront. net/a9mmixlqsuyfzybqzzsa_formate_resonance_hyb rid. jpg. Oxidation number = valence e - (lone pairs + bonding e) An atom with an oxidation number of oxidation state of zero(0) has the same amount of valence electrons as their atomic form.

Related Questions

Experiment 1:

Molecular Models of Neutral Molecules

In this experiment, you will predict the three-dimensional geometry of a series of neutral molecules using the VSEPR theory.

Procedures

Part 1: Use your Periodic Table of Elements to determine the elemental symbol, group number and valence electrons for the elements listed in Table 1.

Table 1: Lewis Dot Structures

Element	Symbol	Group Number	Valence Electrons	Lewis Dot Structure
Hydrogen	H
Carbon	C
Chlorine	Cl
Aluminum
Oxygen	O
Fluorine	F
Neon	Ne
Nitrogen	N

Part 2: Construct the three-dimensional geometry for the molecules listed in Table 2.

Table 2: Molecular Models

Molecule (central atom is underlined)	Shape Name Bond Angle	Bond Angles (more than one may be possible)
CO2	Linear
AlCl3	Trigonal Planar
H2O	Bent
NH3	Trigonal pyramidal
CCl4	Tetrahedral
PCl5	Trigonal bipyramidal
SF6	Octahedral

Post-Lab Questions:

1. What is the molecular geometry (shape) of the methane molecule (CH4)? Explain completely why all the bond angles in methane are equal.

2. What is the molecular geometry (shape) of the chloromethane molecule (CH3Cl)? Explain completely why NOT all of the bond angles in chloromethane are equal.

3. Chloromethane can be thought of as resulting from methane via the replacement of one Hydrogen atom with a Chlorine atom. Subsequent replacements of H with Cl yield dichloromethane (CH2Cl2), trichlormethane (CHCl3) and tetrachlormethane (CCl4). Which of these three previous molecules will have all bond angles equal to each other? Explain completely.

4. Sketch the molecular shape of the compounds in the table below. Be sure to identify the bond angles. H₂ Cl₂ SO₂ NH₃ MoF₆

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8 which of the following solids would have the highest melting point? ( 1) KI (2) KBr (3) KCI (4) KF 9. What type of chemical bond holds the atoms together within a water molecule? (1) polar ionic bond(3) non polar covalent bond (4) coordinate covalent bond 10. Which of the following covalent bonds is the most polar (i.e., highest percent ionic character)? (1) A -CI (2) Si- (3)Al- (4) SI-Ci 11. The total number of valence electrons in the ion SO is (1)32 (2)28 (3)30 (4) 26 12. The Lewis structure reveals a double bond in which of the following molecules? (1)N (2) Br (3) CS: (4) CaHe 13. The Lewis structure reveals an unpaired electron (free radical) in which of the following species? () NO (2)N:O (3) NO (4) NO 14. The number of lone electron pairs in the CIO ion is (1) 12 (2)16 (3)4 (4)0 15. The formal charge on the bromine atom in BrOs drawn with three single bonds is (1)*2 16. Which of the elements listed below would most likely form a polar covalent bond when bonded to sulfur? 17. Give the number of lone pairs around the central atom and the molecular geometry of SeF(1)0 lone 18. According to Molecular Orbital Theory, two separate 1s orbitals interact to form what molecular orbital(l)? 19. The Lewis dot symbol for the S-ion is (2)-1 (1) K (2) Mg (3)C (4)o pairs, tetrahedral (2) 1 lone pair, square pyramidal (3) 1 lone pair, tetrahedral (4) 1 lone pair, distorted tetrahedron (seesaw) (1)oonly (2) Ï only (3) Ï and Ï. (4) Ï and Ï. 2- 20. Which of the following molecules has polar bonds but is a nonpolar molecule? (1) CO (2) Cla 21. Use VSEPR theory to predict the geometry of the SFe molecule. (1) trigonal bipyramidal (2) bent 22. The geometry of the hybrid orbitals about a central atom with sp hybridization is (1) linear (2) bent 23. Which of the following molecules have the same geometries? (1) CO2 and BeHa (2) SFa and CHe 24. According to the VSEPR theory, which one of the following species is linear? (1)HaS (2) SO2 25. Which of the following substances will display an incomplete octet in its Lewis structure? (1) CO2 26. Predict the geometry and polarity of the CS2 molecule. (1) linear, polar (2) linear, nonpolar (3) SO (4) HBr (3) trigonal planar (4) octahedral (3) trigonal planar(4) tetrahedral (3) CO2 and NO2 (4) N2O and NO2 (3) BFs (4) BeF2 (2) NO (3) Cl2 (4) BrCI (3) bent, nonpolar (4) bent, polar

Show transcribed image text 8 which of the following solids would have the highest melting point? ( 1) KI (2) KBr (3) KCI (4) KF 9. What type of chemical bond holds the atoms together within a water molecule? (1) polar ionic bond(3) non polar covalent bond (4) coordinate covalent bond 10. Which of the following covalent bonds is the most polar (i.e., highest percent ionic character)? (1) A -CI (2) Si- (3)Al- (4) SI-Ci 11. The total number of valence electrons in the ion SO is (1)32 (2)28 (3)30 (4) 26 12. The Lewis structure reveals a double bond in which of the following molecules? (1)N (2) Br (3) CS: (4) CaHe 13. The Lewis structure reveals an unpaired electron (free radical) in which of the following species? () NO (2)N:O (3) NO (4) NO 14. The number of lone electron pairs in the CIO ion is (1) 12 (2)16 (3)4 (4)0 15. The formal charge on the bromine atom in BrOs drawn with three single bonds is (1)*2 16. Which of the elements listed below would most likely form a polar covalent bond when bonded to sulfur? 17. Give the number of lone pairs around the central atom and the molecular geometry of SeF(1)0 lone 18. According to Molecular Orbital Theory, two separate 1s orbitals interact to form what molecular orbital(l)? 19. The Lewis dot symbol for the S-ion is (2)-1 (1) K (2) Mg (3)C (4)o pairs, tetrahedral (2) 1 lone pair, square pyramidal (3) 1 lone pair, tetrahedral (4) 1 lone pair, distorted tetrahedron (seesaw) (1)oonly (2) Ï only (3) Ï and Ï. (4) Ï and Ï. 2- 20. Which of the following molecules has polar bonds but is a nonpolar molecule? (1) CO (2) Cla 21. Use VSEPR theory to predict the geometry of the SFe molecule. (1) trigonal bipyramidal (2) bent 22. The geometry of the hybrid orbitals about a central atom with sp hybridization is (1) linear (2) bent 23. Which of the following molecules have the same geometries? (1) CO2 and BeHa (2) SFa and CHe 24. According to the VSEPR theory, which one of the following species is linear? (1)HaS (2) SO2 25. Which of the following substances will display an incomplete octet in its Lewis structure? (1) CO2 26. Predict the geometry and polarity of the CS2 molecule. (1) linear, polar (2) linear, nonpolar (3) SO (4) HBr (3) trigonal planar (4) octahedral (3) trigonal planar(4) tetrahedral (3) CO2 and NO2 (4) N2O and NO2 (3) BFs (4) BeF2 (2) NO (3) Cl2 (4) BrCI (3) bent, nonpolar (4) bent, polar

CHEM101 Lecture 15: February 8: Review, Lewis Dot Structures, Resonance Structures,Picking the Best Resonance Structures (continued), Molecular Shape and Structure (not on first midterm), Electron Group Arrangements and Molecular Shapes, VSEPR Guidelines

CHEM101 Lecture 14: February 6: Breaking the Octet Rule (continued), Formal Atom Charges, Resonance Structures, Electron Delocalization, Picking the Best Resonance Structures.

CHEM101 Lecture 15: February 8: Review, Lewis Dot Structures, Resonance Structures,Picking the Best Resonance Structures (continued), Molecular Shape and Structure (not on first midterm), Electron Group Arrangements and Molecular Shapes, VSEPR Guidelines

CHEM101 Lecture 16: February 11: Electron Group Arrangements and Molecular Shapes: two electron groups,

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