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Chapter 8: Ionic Compounds

8.1 Forming chemical bonds
formation of positive ions, negative ions, electron dot structure, pseudo-noble gas configurations, cation formation of negative ions, anion

8.2 Formation and Nature of Ionic Bonds
form the bond, properties of compounds, formulas (determine charge), name ions & ionic compounds Properties of ionic compounds, electrolyte, lattice energy

8.3 Names and Formulas for Ionic Compounds
metallic bonds, metal alloys, formula unit, monatomic ion, oxidation number, polyatomic ion, oxyanions

8.4 Metallic Bonds and Properties of Metals
Electron sea model, delocalized electrons, metallic bond, alloy, malleable, ductile

The following is an actual summary of this chapter which may be helpful for you:

The bonding in metals is explained by the electron sea model, which proposes that the atoms in a metallic solid contribute their valence electrons to form a “sea” of electrons that surrounds metallic cations. These delocalized electrons are not held by any specific atom and can move easily throughout the solid. A metallic bond is the attraction between these electrons and a metallic cation.

Many of the properties of metals can be explained by means of metallic bonds and delocalized electrons. For example, metals generally have extremely high boiling points because it is difficult to pull metal atoms completely away from the group of cations and attracting electrons. The melting points are considerably lower because of the mobility of the cations and electrons, which can move past each other. Metals are also malleable (able to be hammered into sheets) and ductile (able to be drawn into wire) because of the mobility of the particles. The delocalized electrons make metals good conductors of electricity. These electrons also interact with light, which is why metals tend to be highly lustrous.

A mixture of elements that has metallic properties is called an alloy. Alloys can be of two basic types. A substitutional alloy is one in which atoms of the original metal are replaced by other atoms of similar size. An interstitial alloy is one in which the small holes in a metallic crystal are filled by other smaller atoms.

Here are a few practice problems to check your understanding of this section:
27. An unknown substance is found to be a good conductor of electricity when melted. Explain whether on this basis alone the substance can be classified as a metal.
28. Suppose the substance in question 27 is allowed to solidify. It is then hammered, and shatters as a result. What property is being tested? Would you classify this material as a metal? Explain your answer.
29. A certain sample of an element is known to be either nickel, sulfur, or iodine. The sample is found to be a good conductor of electricity as a solid. Which element is it likely to be? Why? What other properties would you expect the sample to have? 30. Carbon steel is made by filling the holes in an iron crystal with atoms of carbon. As what type of material is such a mixture classified?

31. Brass is a mixture in which some of the atoms in a crystal of copper are replaced by zinc atoms, which are of similar size. As what type of material is such a mixture classified?

If you would like to check your answers to these questions, you can go to Answers to practice problems

  Homework
Section 8.1 Forming Chemical Bonds
Section 8.2 The Formation and Nature of Ionic Bonds
Section 8.3 Names and Formulas for Ionic Compounds
Section 8.4 Metallic Bonds and Properties of Metals
  In Class Assignments
  Lecture Notes
  Standards
  Tests and Quizes
  Tutorials
  Web Helps
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