AP Chemistry Unit 8: Chemical Bonding

Goals:

  • To understand the basic concepts of chemical bonding:
    • ionic and covalent bonds, and the role of electronegativity in distinguishing between bond types and the properties of compounds
    • how lattice energy indicates relative stability of a compound
  • To write Lewis structures:
    • apply the octet rule and 3 types of exceptions
    • use the idea of formal charge to study the distribution of electrons in more detail
  • To use the concept of bond enthalpy to determine the enthalpy of reaction

Course Goals and Essential Questions

  • How can we learn about things that are to small to see?
  • What relationships can I construct among basic concepts, skills, and understandings?
  • How can I best assess my own learning and progress?
  • How can I better use technology in my learning?
  • How can I become a better digital citizen?
  • How can I think more divergently, create, innovate?
  • How can I use my experience in chemistry to learn to think and communicate clearly, logically, and critically in preparation for college and a career?

Prior Knowledge

  • Terms:
    • valence electrons
    • core electrons
    • Lewis structure
    • cation, anion
    • oxidation number
  • Names of families on the periodic table, and the descriptions and names of elements found in each

Prior Skills

  • Draw Lewis dot sctuctures for atoms, simple compounds, and some ions
  • Determining oxidation numbers
  • Use Hess's Law to determine enthalpy change
Learning Targets Ch. 9.1 Lewis Dot Symbols Q&P 9.1-9.5

Students will know....

  • How Lewis dot structures for atoms are drawn

Students will be able to....

  • Identify the valence electrons for all representative elements.
Learning Targets Ch. 9.2 The Ionic Bond RQ 9.6-9.14, Prob. 9.15-9.20

Students will know....

  • Term: ionic bond

Students will be able to....

  • Rationalize why alkali metals and alkaline earth metals usually form cations and oxygen and the halogens usually form anions using Lewis dot symbols in the discussion.
  • Use Lewis dot symbols to show the formation of ionic compounds.
Learning Targets Ch. 9.3 Lattice Energy of Ionic Compounds RQ 9.21-9.24; Prob. 9.25-9.26

Students will know....

  • Terms:
    • lattice energy
    • Coulomb’s law
    • Born-Haber cycle.

Students will be able to....

  • Demonstrate how the Born-Haber cycle is an application of Hess’s law and use the Born-Haber cycle to determine lattice energy for an ionic solid.
Learning Targets Ch. 9.4 The Covalent Bond RQ 9.27-9.32; prob. 9.33-9.34

Students will know....

  • Terms:
    • covalent bond
    • covalent compound
    • molecular compound
    • single, double, triple bond
    • bond length

Students will be able to....

  • Use Lewis dot symbols to show the formation of covalent compounds.
  • Identify covalent compounds, the type of covalent bonds present, and the number of lone pairs of electrons using Lewis structures.
  • Relate types of bonds to bond length and bond strength.
  • Compare and contrast various properties expected for ionic compounds versus covalent compounds.
Learning Targets Ch. 9.5 Electronegativity RQ 9.33-9.34; Prob. 9.35-9.40

Students will know....

  • Terms:
    • electronegativity
    • covelent
    • polar covalent
    • nonpolar covalent
    • coordinate covalent

Students will be able to....

  • Identify ionic, polar covalent and (nonpolar) covalent bonds using the concepts of electronegativity.
  • Predict the relative changes in electronegativity with respect to position on the periodic table.
  • Use the concept of electronegativity to rationalize oxidation numbers
Learning Targets Ch. 9.6 Writing Lewis Structures RQ 9.41-9.42; Prob. 9.43-9.48

Students will know....

  • Rules for writing Lewis dot structures
  • The octet rule

Students will be able to....

  • Use Lewis dot structure rules and the octet rule to write Lewis structures of compounds and ions.
Learning Targets Ch. 9.7 Formal Charge and Lewis Structure

Students will know....

  • The definition of formal charge

Students will be able to....

  • Apply the concept of formal charge to predict the most likely Lewis structure of a compound.
Learning Targets Ch. 9.8 The Concept of Resonance RQ 9.49-9.50; Prob. 9.51-9.56

Students will know....

  • The meaning of the term resonance

Students will be able to....

  • Explain how Lewis structures are inadequate to explain observed bond length (bond types) in some compounds and how the concept of resonance must be invoked.
Learning Targets Ch. 9.9 Exceptions to the Octet Rule RQ 9.57-9.60; Prob. 9.61, 9.66

Students will know....

  • Three types of molecules for which the octet rule fails

Students will be able to....

  • Recall several common examples in which the octet rule fails.
  • Demonstrate, using Lewis structures, the formation of a coordinate covalent (dative) bond.
Learning Targets Ch. 9.9 Bond Enthalpy RQ 9.67-9.68; Prob. 9.69-9.72

Students will know....

  • Why enthalpy change for breaking chemical bonds is positive and the formation of chemical bonds is negative.

Students will be able to....

  • Use Lewis structures and bond energies to predict heats of reaction.
Daily Learning Activities
Day 26
  • Chapters 9.1-9.6
Day 27
  • Chromatography Lab
Day 28
  • Chapters 9.7-9.9

Links and Resources

Lattice Energy explanation and examples, from Oklahoma State University
Writing good responses to AP Bonding questions - from Adrian Dingle


 

L. C. Lee 1990-2012
Creative Commons License
This work by Luann Christensen Lee is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
Based on a work at www.chemistar.com.

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