ellanti

Worksheet on HRW’s Chapter 6: Molecular Compounds

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This chatper contains five simple sections except the last one.

I would encourage teachers to do open book test on this chapter as kids do need periodic table as well as some material from the chapter that better be used as reference than memorize.

Some of the concepts are too advanced, particularly the mlecular geometry. Could have been avoided or introduced later when needed to explain something else.  

  1. Introduction to Chemical bonds
  2. Covalent Bonding and Molecular Compounds
  3. Ionic Bonding and Ionic Compounds
  4. Metallic Bonding
  5. Molecular Geometry

Time permitting, I would love to continue the hypothetical atom house story and build on that to introduce formation of compounds and attractions/repulsions in thus formed complex structures.

For now, kids should be able to benefit from just doing this practice worksheet using open book.

Parents and teachers can coach using the questions which are all from HRW book. These are good set of questions to help quickly get most of the concepts from the chapter into their brains if they are strapped for time and can’t read the lengthy and verbose chapter.

Another very useful worksheets is here


Introduction to Chemical Bonding

1. What is a chemical bond?

2. Identify and define the three types of chemical boding?

3.What is the relationship between electronegativity and the ionic character of a chemical bond?

4a) What is the meaning of the term polar, as applied to chemical bonding?

4b) Distinguish between polar-covalent and nonpolar-covalent bonds. 

5.What determines whether atoms will form chemical bonds?

6. Determine the electronegativity difference, the probable and bond type, and the more electronegative atom with respect to bonds formed between the following pairs of atoms

   Electronegativity difference   Bond type  Electronegative  atom in the bond
 H and I      
 S and O      
 K and Br      
 Si and Cl      
 K and Cl      
 Se and S      
 C and H      

7. Assign rank to the bonding pairs in order of increasing covalent character with 1 being least covalent and 7 being the most covalent.

   Rank
 H and I  
 S and O  
 K and Br  
 Si and Cl  
 K and Cl  
 Se and S  
 C and H  

8. Use orbital notation to illustrate the bonding in each of the following molecules:

   Answer
 Chlore,Cl2  
 Oxygen, O2  
 Hydrogen Fluoride, HF  

9. The lattice energy of sodium chloride, NaCl, is -787.5 kJ/mol. The lattice energy of potassium chloride, KCL, is -715 kJ/mol. In which compound is the bonding between ions stronger? Why?

Covalent Bonding and Molecular Compounds


10. What is a molecule?

11.a) What determines bond length?

11.b) How are bond energies and bond lengths related?

12. Describe the general location of the electrons in a covalent bond.

13. As applied to covalent bonding, what is meant by an unshared or line pair of electrons?

14.Describe the octet rule in terms of noble-gas configurations and potential energy?

15.Determine the number of  valence electrons in an atom of each of the following elements

  Answer
  H  
  F  
  Mg  
  O  
  Al  
  N  
 C  

16. When drawing Lewis structures, which atom is usually the central atom? 

17. Distinguish between single, double, and triple covalent bonds by defining each and providing an illustration of each type.

18. In writing Lewis structures, how is the need for multiple bonds generally determined?

19. Use electron-dot notation to illustrate the number of valence electrons present in one atom of each of the following elements.

   Answer
 Li  
 Ca  
 Cl  
 O  
 C  
 P  
 Al  
 S  

20. Use electron-dot structure to demonstrate the formation of ionic compounds involving the following elements:

   Answer
 Na and S   
 Ca and O  
 Al and S  

21. Draw Lewis structures for each of the following molecules

   Answer
 One C and four F atoms  
 Two C and one Se atom  
 Two N and one I atoms  
 One  Si and one Br atoms  
 One C and one Br atoms  
 One C, one Cl, and three H atoms  

22. Determine the type of hybrid orbitals formed by the boron atom in a molecule of boron fluoride, BF3.

23.Draw Lewis structures for each of the following molecules. Show resonance structures if they exist.

   Answer
 O2  
 N2  
 CO  
 SO2  

24. Draw Lewis structures for each of the following molecules. Show resonance structures if they exist.

   Answer
 OH  
 H2 C2 02  
 Br 03  

Ionic Bonding and Ionic Compounds


25.a) What is an ionic compound?
 

25.b) In what forms do most ionic compounds occur?

26.a) What is a formula unit?

26.b) What are the components of one formula unit of CaF2

27.a) What is lattice energy?

27.b) What is the relationship between lattice energy and the strength of ionic bonding?

28.a) How do ionic and molecular compounds compare in terms of melting points, boiling points, and ease of vaporization?

28.b) What accounts for the observed difference in the properties of ionic and molecular compounds?

28.c) Cite three physical properties of ionic compounds?

29.a) What is a polyatomic ion?

29.b) Give two examples of polyatomic ions?

29.c) In what form do such ions often occur in nature?

Metallic Bonding


30.a ) How do the properties of metals differ from those of both ionic and molecular compounds?

 

30.b) What specific property of metals accounts for their unusual electrical conductivity?

31. What properties of metals contribute to their tendency to form metallic bonds?
 

32.a) What is metallic bonding?
 

32.b)how can the strength of metallic bonding be measured?

Molecular Geometry


33.a) How is the VSEPR theory used to classify molecules?

 

33.b) What molecular geometry would be expected for F2 and HF

34)ccording to the VSEPR theory, what molecular geometries are associated with the following

   Answer
 AB2  
 AB3  
 AB4  
 AB5  
 AB6  

35. Describe the role of each of the following in predicting molecular geometries:

a) Unshared electron pairs

b) Double bonds

36.a)  What are hybrid orbitals?

36.b) What determines the number of hybrid orbitals produced by the hybridization of an atom?

37.a) What are intermolecular forces?

37.b) How do these forces compare in strength with hose in ionic and metallic bonding?

38.What is the relationship between electronegativity and the polarity of a chemical bond?

39.a) What are dipole-dipole forces?

39.b) What determined the polarity of a molecule?

40.a) What is meant by an induced dipole?

40.b) What is the everyday importance of this type of intermolecular force?

41.a) What is hydrogen bonding? 

 

41.b) What accounts for its extraordinary strength?

42. What are London dispersion forces? 

Practice Problems


43. According the VSEPR theory, what molecular geometries are associated with the following types of molecules?

44. Use hybridization to explain the bonding in methane,  CH4

   Answer
 AB2E  
 AB3E2  
 AB2 E  

45. For each of the following polar molecules, indicate the direction of the resulting dipole:

   Answer
 H-F  
 H-Cl  
 H-Br  
 H-I  

46. For each of the following polar molecules, indicate the direction of the resulting dipole:

   Answer
 H-H  
 H-O  
 H-F  
 Br-Br  
 H-Cl  
 H-N  

47. On the basis of individual bond polarity and orientation, determine whether each of the following molecules would be polar or nonpolar:

   Answer
 H2O  
 I2  
 CF2  
 NH3  
 CO3  

48. Draw a Lewis structure for each of the following molecules, and then use the VSEPR theory to predict the molecular geometry of each:

   Answer
 SCl2  
 PI3  
 Cl2O  
 NH2 Cl  
 SiClCl3 Br  
 ONCl  

49. Draw a Lewis structure for each of the following polyatomic ions, and then use the VSEPR theory to determine the geometry of each: 

   Answer
 NO3  
 NH4  
 SO42-  
 ClO2   

Note: this is meant for use by kids, teachers, and parents working with this text book. Please don’t copy. Follow copy right notice of original HRW book. The questions are word-for-word from the book and therefore please don’t copy this into any commerical works based ont these questions.

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Written by ellanti

December 14, 2011 at 5:07 am

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