1. Copyright © Houghton Mifflin Company. All Rights Reserved.1 Chemistry 6/e Steven S. Zumdahl and Susan A. Zumdahl Chapter 8: BONDING: GENERAL CONCEPTS

2. Copyright © Houghton Mifflin Company. All Rights Reserved.2 Bonding: General Concepts Types of Chemical BondsTypes of Chemical Bonds React 1 Electronegativity React 2 323 Bond Polarity and Dipole MomentsBond Polarity and Dipole Moments React 4 5 6456 Ions: Electron Configurations and SizesIons: Electron Configurations and Sizes React 7 Formation of Binary Ionic CompoundsFormation of Binary Ionic Compounds React 8 9 10 11891011 React 12 13 14121314

3. Copyright © Houghton Mifflin Company. All Rights Reserved.3 Questions to Consider What is meant by the term “chemical bond?” Why do atoms bond with each other to form molecules? How do atoms bond with each other to form molecules?

4. Copyright © Houghton Mifflin Company. All Rights Reserved.4 Types of Chemical Bonds

5. Copyright © Houghton Mifflin Company. All Rights Reserved.5 The Interaction of Two Hydrogen Atoms

6. Copyright © Houghton Mifflin Company. All Rights Reserved.6 Energy profile as a function of the distance between the nuclei of the hydrogen atoms As the atoms approach each other (right side of graph), the energy decreases until the distance reaches 0.074 nm (0.74 Å) and then begins to increase again due to repulsions.

7. Copyright © Houghton Mifflin Company. All Rights Reserved.7 Key Ideas in Bonding Ionic Bonding: Electrons are transferred Covalent Bonding: Electrons are shared equally What about intermediate cases?

8. Copyright © Houghton Mifflin Company. All Rights Reserved.8 The Effect of an Electric Field on Hydrogen Fluoride Molecules

9. Copyright © Houghton Mifflin Company. All Rights Reserved.9 What is meant by the term “chemical bond”? Why do atoms bond with each other to form molecules? How do atoms bond with each other to form molecules? React 1

10. Copyright © Houghton Mifflin Company. All Rights Reserved.10 Electronegativity

11. Copyright © Houghton Mifflin Company. All Rights Reserved.11 If lithium and fluorine react, which has more attraction for an electron? Why? In a bond between fluorine and iodine, which has more attraction for an electron? Why? React 2

12. Copyright © Houghton Mifflin Company. All Rights Reserved.12 What is the general trend for electronegativity across rows and down columns on the periodic table? Understand this trend, do not merely memorize it. React 3

13. Copyright © Houghton Mifflin Company. All Rights Reserved.13 The Pauling Elecronegativity Values Electronegativity generally increases across a period and decreases down a group.

14. Copyright © Houghton Mifflin Company. All Rights Reserved.14 The Relationship Between Electronegativity and Bond Type Electronegativity Difference in the Bonding Atoms Bond Type ZeroCovalent IntermediatePolar Covalent LargeIonic Covalent character decreases; ionic character increases

15. Copyright © Houghton Mifflin Company. All Rights Reserved.15 Bond Polarity and Dipole Moments

16. Copyright © Houghton Mifflin Company. All Rights Reserved.16 Arrange the following bonds from most to least polar: I. N-FO-FC-F II. C-FN-OSi-F III. H-ClB-ClS-Cl React 4

17. Copyright © Houghton Mifflin Company. All Rights Reserved.17 Which of the following bonds would be the least polar yet still be considered polar covalent? Mg-O C-OO-OSi-ON-O React 5

18. Copyright © Houghton Mifflin Company. All Rights Reserved.18 Which of the following bonds would be the most polar without being considered ionic? Mg-O C-OO-OSi-ON-O React 6

19. Copyright © Houghton Mifflin Company. All Rights Reserved.19 Ions: Electron Configurations and Sizes

20. Copyright © Houghton Mifflin Company. All Rights Reserved.20 Choose an alkali metal, an alkaline metal, a noble gas, and a halogen so that they constitute an isoelectronic series when the metals and halogen are written as their most stable ions. What is the electron configuration for each species? Determine the number of electrons for each species. Determine the number of protons for each species. Rank the species according to increasing radius. Rank the species according to increasing ionization energy. React 7

21. Copyright © Houghton Mifflin Company. All Rights Reserved.21 Sizes of Ions Related to Positions of the Elements in the Periodic Table Note that size generally increases down a group. Also note that in a series of isoelectronic ions, size decreases with increasing atomic number. The ionic radii are given in units of picometers.

22. Copyright © Houghton Mifflin Company. All Rights Reserved.22 What we can “read” from the periodic table: Trends for –Atomic size –Ion radius –Ionization energy –Electronegativity Electron configurations Predicting formulas for ionic compounds Ranking polarity of covalent bonds

23. Copyright © Houghton Mifflin Company. All Rights Reserved.23 Formation of Binary Ionic Compounds

24. Copyright © Houghton Mifflin Company. All Rights Reserved.24 Comparison of the energy changes involved in the formation of solid sodium fluoride and solid magnesium oxide.

25. Copyright © Houghton Mifflin Company. All Rights Reserved.25 The relationship between the ionic character of a covalent bond and the electronegativity difference of the bonded atoms

26. Copyright © Houghton Mifflin Company. All Rights Reserved.26 For a given molecule we want to: Describe the valence electron arrangement in the molecule (Lewis structure) Predict the geometry (VSEPR) Specify the atomic orbitals involved in the molecule

27. Copyright © Houghton Mifflin Company. All Rights Reserved.27 Lewis Structures 1.Sum the valence electrons. 2.Place bonding electrons between pairs of atoms. 3.Atoms usually have noble gas configurations.

28. Copyright © Houghton Mifflin Company. All Rights Reserved.28 Draw a Lewis structure for each of the following molecules: H 2 N 2 O 2 F 2 React 8

29. Copyright © Houghton Mifflin Company. All Rights Reserved.29 Draw a Lewis structure for each of the following molecules: H 2 ONH 3 React 9

30. Copyright © Houghton Mifflin Company. All Rights Reserved.30 Draw a Lewis structure for each of the following molecules: COCO 2 H 3 COHBF 3 C 2 H 6 OPCl 5 NO 3 - SF 6 React 10

31. Copyright © Houghton Mifflin Company. All Rights Reserved.31 VSEPR To approximate molecular geometries: 1.Write Lewis structure. 2.Count electron pairs. 3.Choose an arrangement that minimizes electron-pair repulsions.

32. Copyright © Houghton Mifflin Company. All Rights Reserved.32 Determine the shape of each of the following molecules including bond angles: HCN PH 3 SF 4 O 3 KrF 4 React 11

33. Copyright © Houghton Mifflin Company. All Rights Reserved.33 If you are asked to determine the shape of a molecule, what is always the first step? How do we deal with multiple bonds with VSEPR theory? If more than one atom can break the octet rule in a molecule, what do we do? React 12

34. Copyright © Houghton Mifflin Company. All Rights Reserved.34 True or false: A molecule that has polar bonds will always be polar. If true, explain why. If false, provide a counterexample. React 13

35. Copyright © Houghton Mifflin Company. All Rights Reserved.35 True or false: Lone pairs make a molecule polar. If true, explain why. If false, provide a counterexample. React 14