Name_________________________________________________period____________Unit 3 worksheet
Read chapter 8, 2.5-2.7
1. Explain the difference between metallic, ionic, and covalent bonding
Metallic- cations share a sea of electrons
Ionic- atoms give and take electrons
Covalent- atoms share electrons
2. Why can metals conduct electricity?
electrons are free to move around
3. Predict the chemical formula of the ionic compound formed between the following pairs of elements
a. Al and F
b. K and S
c. Mg and N
d. Ba and O
AlF3
K2S
Mg3N2
BaO
4. Define the term lattice energy and tell what factors govern the magnitude of the lattice energy of an ionic
compound. The amount of energy that is required to break an ionic bond. The magnitude depends on the
charge of the ion and the size of the ion. smaller ions and more charge have higher lattice energy.
5. Arrange the following substances according to their expected lattice energies, listed them from lowest lattice
energy to highest: LiCl, KCl, KBr, CaO
KBr< KCl < LiCl < CaO
6. a. The lattice energies of NaF and MgO are given in table 8.2. Account for the difference in these two quantities.
MgO has higher charges so the lattice energy is higher
b. Account for the difference in the lattice energies of MgCl2 and SrCl2, which are also listed in the table.
Mg is smaller than Sr, so the lattice is greater
7. Explain the following trends in lattice energy
a. MgO > MgS
b. LiF > CsBr
c. CaO > KF
Oxygen is smaller than S
Cs is larger than Li
CaO has larger charges than KF
Br is larger than F
8. How is bonding in Cl2 different than NaCl?
In Cl2, the electrons are being shared between the two chlorine atoms, but in NaCl, the Cl is taking the electron
from the sodium
9. Explain why a Br atom in Br2 satisfies the octet rule whereas a free Br atom does not.
Br has 7 valence electrons, but when it bonds to itself they both contribute an electron to share so they each
feel 8 electrons around them.
10. Draw the Lewis structure for O2. The bond in O2 is shorter than the O-O single bond. Explain this observation.
O=O
A double bond is shorter than a single bond
11. Predict whether the following compounds are molecular or ionic
a. B2H6
b. CH3OH
c. LiNO3
d. Sc2O3
e. CsBr
f. NOCl
g. Ag2SO4
Molecular
molecular
ionic
ionic
ionic
covalelnt
ionic
12. Which of the following bonds are polar?
a. P-O
b. S-F
c. Br-Br
13. Arrange the bonds in order of increasing polarity
a. C-F, O-F, Be-F
b. N-Br, P-Br, O-Br
O-F, C-F, Be-F
P-Br, N-Br, O-Br
14. Label each compound as ionic, polar covalent, or nonpolar covalent
a. CO
b. MgO
c. Cl2
Polar covalent
ionic
nonpolar covalent
15. Draw the Lewis structure for the following see in class
a. CO
b. N2
c. SF2
d. ClO2-
d. AlF3
e. PCl3
ionic
e. H2CO (both H bonded to C)
16. A.Draw the Lewis electron-dot structures for CO32-, CO2 and CO, including resonance structures where
appropriate.
See in class
b. Which of the three species has the shortest C-O bond length? Explain the reason for your answer.
CO carbon monoxide forms triple bonds which are shorter than double in CO2 and the 1 1/3 bond in CO3
c. Account for the fact that the carbon-oxygen bond length in CO32– is greater than the carbon-oxygen bond
length in CO2.
1 1/3 bond is longer than a double bond
17. How can the concept of resonance be used to explain that all six C-C bonds in benzene are equal in length.
The 3 double bonds are being shared between all 6 atoms so the bond order for each C-C bond is 1.5
18. Use simple structure and bonding models to account for each of the following:
(a) The bond length between the two carbon atoms is shorter in C2H4 than in C2H6.
C2H4 forms double bonds and C2H6 forms single bonds. Double bonds are shorter than single
(b) All the bond lengths in SO3 are identical and are shorter than a sulfur-oxygen single bond.
SO3 forms resonance so the bonds are each 1 1/3 which is shorter than a single
19. Draw the Lewis structure for each of the following molecules see in class
a. CO32b. BH3
c. I3d. XeF4
e. AsF620. In the Lewis structure for CH2Cl2, the number of unshared electron pairs
a. 2
b. 8
c. 10
d. 6
e. 4
21. In which of the following compounds does the bond between the central atom and chlorine have the greatest
ionic character?
a. BCl3
b. HCl
c. FeCl2
d. CCl4
e. CaCl2
22. Nitrogen is the central atom in each of the species given above. Draw the Lewis electron-dot structure for each
of the three species. See in class
23. Which one of the following molecules contains a triple bond?
a. PF3
b. NF3
c. C2H2
d. H2CO
e. HOF
24. Which of the following has the greatest dipole moment?
a. H2
b. HCl
c. HF
d. CO
25. Which of the following will conduct electricity? (there can be more than one answer)
a. solid Mg
b. solid NaCl
c. aqueous MgCl2
d. liquid Sn
e. solid CO2
f. liquid N2
26. Predict which of the following will have the highest boiling point
a. CO2
b. N2
c. NaCl
27. Which of the following ionic compounds has the smallest lattice energy?
a. Na2O
b. LiF
c. CaO
d. CaCl2
e. MgS
28. What are structural isomers? Draw two isomers of pentane. See in class
29. give the formula for each of the following
a. pentane
C5H12
c. 2-Hexene C6H12
e. 1-butyne C4H6
g. benzene C6H6
b. heptane C7H16
d. proponol C3H7OH
f. ethane C2H6
h. methane CH4
30. Calcium reacts with element X to form an ionic compound. If the ground-state electron configuration of X is
1s22s22p4, what is the simplest formula for this compound?
a. CaX
b. CaX2
c. Ca4X2
d. Ca2X2
Nonmetal
Ne
Si
P
S
Ar
No
SiF4
PF3
SF2
No
compound
compound
31. Some binary compounds that form between fluorine and various nonmetals are listed in the table above. A
student examines the data in the table and poses the following hypothesis: the number of F atoms that will
bond to a nonmetal is always equal to 8 minus the number of valence electrons in the nonmetal atom.
(a) Based on the student’s hypothesis, what should be the formula of the compound that forms between
chlorine and fluorine?
ClF
(1 point is earned for correct formula)
Formula of
compound
C
CF4
N
NF3
O
OF2
(b) In an attempt to verify the hypothesis, the student researches the fluoride compounds of the other halogens
and finds the formula ClF3 . Draw a complete Lewis electron-dot diagram for a molecule of ClF3 .
see in class
(1 point is earned for a central Cl atom surrounded by three bonding pairs with F atoms and two nonbonding
(lone) pairs of electrons. F atoms must have three nonbonding pairs each. Electron pairs can be depicted as
dots or line segments
In an attempt to resolve the existence of the ClF3 molecule with the hypothesis stated above, the student researches the
compounds that form between halogens and fluorine, and assembles the following list
Halogen
Formula(s)
F
F2
Cl
Br
BrF, BrF3, BrF5
I
IF, IF3, IF5, IF7
(c). Based on concepts of atomic structure and periodicity, propose a modification to the student’s previous
hypothesis to account for the compounds that form between halogens and fluorine.
An acceptable hypothesis must include the following ideas:
1. Atomic structure: e.g., odd number of F atoms
2. Periodicity: e.g., as the atomic number of the central halogen atom increases, the number of F
atoms increases
(1 point is earned for an acceptably modified hypothesis that addresses both atomic structure and
periodicity)
32. Bronze (Cu and Sn); Steel (Fe and C). Which of the following correctly describes the malleability of both alloys
compared to their primary metal?
b. Bronze’s malleability would be comparable to that of copper, but steel’s malleability would be
significantly lower than that of iron.
c. Bronze’s malleability would be significantly higher than that of copper, but steel’s malleability would be
comparable to that of iron.
d. Both bronze and steel would have malleability values similar to those of their primary metals
e. Both bronze and steel would have malleability values greater than those of their primary metal.
Review
33. Calcium reacts with element X to form an ionic compound. If the ground-state electron configuration of X is
1s22s22p4, what is the simplest formula for this compound?
a. CaX
b. CaX2
c. Ca4X2
d. Ca2X2
34. A. What are valence electrons?
Electrons in the highest energy level
a. How many valence electrons does nitrogen have?
5
c. An atom has the electron configuration 1s22s22p63s23p2. How many valence electrons does this atom have?
4
35. If an atom has the electron configuration 1s22s22p5, how many electrons must it gain to achieve an octet?
1
36. Fill in the gaps
52 3+
130 107
119
75
Symbol
Cr
I
Ag+
Sn2+
As3Protons
24
53
47
50
33
Neutrons
28
77
60
69
42
Electrons
21
54
46
48
36
Net charge
3+
11+
2+
337. What is the nuclear charge for the following atoms
a. Na
b. F
c. Sn
d. P
e. Ar
11
9
50
15
18
38. Why doesn’t a valence electron “feel” the full nuclear charge of an atom?
The nucleus is shielded by other electrons
39. Which atom will have the largest radius in each pair.
a. K, Na
b. Na, Na+
c. Br, Br-
d. K, Br
40. Which property generally increases down a group but decreases from left to right
b. Melting point b. electronegativity
c. ionization energy
d. atomic radius
41. A.What is the name of group 1? Alkali metals
b. What is the name of group 17? halogens
42. Which pair of elements has the most similar properties?
c. Na, S
b. N, P
c. P, Cl
d. N, Cl
43. Convert
d. 67.5 g of magnesium chloride to moles
0.708 mol
e. 5.3 x 1023 molecules of nitrogen dioxide to grams
41 g
f.
0.761 moles of ammonia to milligrams
12900 mg
44. Write the electron configuration for each of the following ions
c. Sr2+
b. Ni2+
c. Br[Kr]
[Ar]3d8
[Ar]4s23d104p6
d. Mn3+
[Ar]3d4
45. Write a balanced net ionic reaction
a. manganese (II) nitrate solution is mixed with sodium hydroxide solution.
2+
Mn + 2OH  Mn(OH)2
b. hydrosulfuric acid is added to a solution of barium hydroxide and a precipitate forms.
2+
2H2S + Ba + 2OH  BaS + 2H2O
c. fluorine is added to a magnesium chloride solution. Halogens are soluble except with silver, mercury, and lead
F2 + 2Cl-  Cl2 +2 Fd. potassium is added to water
+
K + H2O  K + OH + H2
46. Which is a list of elements listed in order of increasing ionization energy?
A) Na, K, Rb
B) Ne, Ar, Kr
C) Al, Mg, Na
D) Br, Cl, F
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
Name or give the formula for each of the following
silver sulfide
Ag2S
sodium sulfite
Na2SO4
magnesium sulfate
MgSO4
iron (III) sulfide
Fe2S3
zinc phosphate
Zn3(PO4)2
hydrosulfuric acid
H2S
barium acetate
Ba(C2H3O2)2
copper (I) permanganate
CuMnO4
carbonic acid
H2CO3
strontium cyanide
Sr(CN)2
dinitrogen trioxide
N2O3
silver nitride
Ag3N
hydrobromic acid
HBr
calcium hydroxide
Ca(OH)2
nitric acid
HNO3
acetic acid
HC2H3O2
ammonia
NH3
E) O, S, Se
64. MnO
manganese (II) oxide
65. P5O4
pentaphosphorus tetroxide
66. Fe(OH)2
iron(II) hydroxide
67. NiCr2O7
nickel(II) dichromate
68. Cu2S
copper (I) sulfide
69. HCl
hydrochloric acid
70. CO
carbon monoxide
71. H2SO3
sulfurous acid
72. Cs2CO3
cesium carbonate
73. NH4ClO4
ammonium perchlorate
74. Ba(CH3COO)2 barium acetate
75. FePO4
iron (III) phosphate
calcium fluoride
76. CaF2
77. H3PO4
phosphoric acid
78. MgBr2
magnesium bromide
79. NaHCO3
sodium bicarbonate
80. H2O2
hydrogen peroxide