Chapter 7 Summary

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CHAPTER 7

Building Molecules

SUMMARY

KEY TERMS

ball-and-stick model

tetrahedral shape

electron domain

electron domain theory

pyramidal shape

bent shape

trigonal planar shape

linear shape

space-filling model

receptor site theory

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Smells Update

The smell of a substance sometimes has more to do with molecular shape than with the functional groups that are present. In this chapter, you learned about three-dimensional molecular structure and related it to smell. Ball-and-stick and space-filling models show how atoms are arranged within a molecule. The actual shape of a molecule is determined by the locations of electron domains.

No matter what shape a molecule has, it must fit into an appropriate receptor site in order for the nose to detect its smell.

REVIEW EXERCISES

Question 7.1

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1. Examine the ball-and-stick model for propyl acetate.

  1. What is the molecular formula for this molecule?

  2. Draw the Lewis dot structure and the structural formula.

  3. What functional group is in the molecule?

  4. Predict the smell of the compound.

Question 7.2

2. Predict the shape of each molecule. Support your answer.

  1. ammonia, NH3

  2. silicon chloride, SiCl4

  3. hydrogen sulfide, H2S

  4. hydrogen cyanide, HCN

  5. formaldehyde, CH2O

Question 7.3

3. Explain what determines a molecule’s shape.

Question 7.4

4. Draw a possible Lewis dot structure for C4H10O.

Question 7.5

5. From what you’ve learned so far, how is molecular shape related to smell?