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Chapter 5
Chemical Bonding
Practice Problems
Problem 1
Which of the following properties would mostly be associated with a molecular
compound?
(a) melting point is 600oC
(b) gives off a distinct odour
(c) boiling point is 88.5oC
(d) liquid at room temperature
(e) hard crystals that break leaving distinct flat surfaces
Problem 2
Which elements shown are in the same group?
(a)
(b) element of atomic number 32
(c)
(d) element of atomic number 52
Problem 3
Use Lewis diagrams to show how the following elements will combine to form an ionic
compound. Write the chemical formula of each compound.
(a) cesium and sulfur
(b) strontium and iodine
(c) aluminum and fluorine
(d) barium and nitrogen
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Problem 4
For each set of atoms listed, use a Lewis structure to illustrate how they can combine by
sharing electrons to form a compound.
(a) 2 carbon atoms and 6 hydrogen atoms
(b) 2 carbon atoms, 4 hydrogen atoms, and 2 fluorine atoms
(c) 2 carbon atoms, 4 hydrogen atoms and one oxygen atom
(d) 1 carbon atom, 1 hydrogen atom, and 3 chlorine atoms
Problem 5
Draw a structural formula that corresponds to the each Lewis structure in question 4.
Problem 6
Use your understanding of the nature of a covalent bond to predict if the compound C2
can exist.
Problem 7
Examine the compounds that follow. Correct the structures that have errors.
(a)
(b)
(c)
Problem 8
Represent each of the following molecules with a structural formula:
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(a) PCl3
(b) C2H4O
(c) CH2Cl2
(d) SiH4
(e) CH2O2
Problem 9
Use the table of electronegativities listed in the student textbook to predict whether the
bond formed between each pair of atoms will be non-polar covalent, polar covalent, or
ionic.
(a) Cs and O
(b) Fe and N
(c) H and Br
(d) Ag and S,
(e) O and Cl
Problem 10
Examine the structural formula of the molecule shown below and calculate ∆E for each
bond in the molecule. Based upon the calculated value of ∆E, list the bonds in decreasing
order of polarity.
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classroom only. McGraw-Hill Ryerson Limited shall not be held responsible for content if any revisions, additions, or deletions are made to this page.
Answers
1.
Properties (b), (c), and (d) would be associated with a molecular compound.
2.
(b) and (c) are in the same group since each has 4 valence electrons
3. (a)
(b)
(c)
(d)
4.
(a)
(b)
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(c)
(d)
5. (a)
(b)
(c)
(d)
6.
This compound could theoretically exist and satisfy the octet rule by forming 4 covalent
bonds between the two carbon atoms. It is unlikely to exist in this way because there
would be two much negative charge between the two atoms to remain stable.
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classroom only. McGraw-Hill Ryerson Limited shall not be held responsible for content if any revisions, additions, or deletions are made to this page.
7.
(a) and (b) are incorrect and should be drawn as follows:
8. (a)
(b)
(c)
(d)
(e)
9.
Use the following criteria: non-polar covalent ∆E < 0.5; polar covalent, ∆E between 0.5
and 1.7; ionic ∆E > 1.7
(a) Cs and O, ∆E = 3.44 – 0.79 = 2.65, ionic
(b) Fe and N, ∆E = 3.04 – 1.83 = 1.21, polar covalent
(c) H and Br, ∆E = 2.96 – 2.20 = 0.76, polar covalent
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(d) Ag and S, ∆E = 2.58 – 1.93 = 0.65, polar covalent
(e) O and Cl, ∆E = 3.44 – 3.16 = 0.28, covalent
10.
ranking from most polar to least polar:
O–H: ∆E = 3.44 – 2.20 = 1.24 (most polar)
C=O and C–O: ∆E = 3.44 – 2.55 = 0.89
C–Cl: ∆E = 3.16 – 2.55 = 0.61
H–C: ∆E = 2.55 – 2.20 = 0.35
C–C: ∆E = 2.55 – 2.55 = 0 (least polar)
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classroom only. McGraw-Hill Ryerson Limited shall not be held responsible for content if any revisions, additions, or deletions are made to this page.