UNIT
2 Review
K/U
Knowledge/Understanding Knowledge
For each question, select the best answer from the four
alternatives.
1. Which of these statements correctly describes the
nucleus of an atom? (3.1) K/U
(a) It is neutral.
(b) It is positively charged and very dense.
(c) It contains protons and electrons.
(d) It has a small mass compared to the rest of the
atom.
2. Which of the following correctly describes a neutron?
(3.1) K/U
(a) It is located in the nucleus.
(b) It has no charge.
(c) It has approximately the same mass as a proton.
(d) all of the above
3. The mass number of an atom is
(a) the number of protons in the nucleus
(b) the sum of the protons and electrons
(c) the sum of the protons and neutrons
(d) the sum of the protons, neutrons, and electrons
(3.1) K/U
4. Which of the following pairs of symbols represents
isotopes of the same element? (3.1) K/U
12
(a) 12
6C and 7C
13
(b) 12
6C and 7C
12
(c) 6C and 12
6C
12
(d) 6C and 13
6C
5. A neutral atom has an atomic number of 26 and a
mass number of 58. How many protons, neutrons,
and electrons does the atom have? (3.1) K/U
(a) 26 protons, 26 neutrons, and 26 electrons
(b) 58 protons, 26 neutrons, and 26 electrons
(c) 26 protons, 32 neutrons, and 26 electrons
(d) 26 protons, 58 neutrons, and 32 electrons
6. What is the name given to the observation that
electrons are emitted from matter after the matter
absorbs energy from short waves of electromagnetic
radiation? (3.2) K/U
(a) the photoelectric effect
(b) blackbody radiation
(c) quantum theory
(d) the Pauli exclusion principle
272 Unit 2 • Structure and Properties of Matter
436900_Chem_CH04_P255-279.indd 272
T/I
Thinking/Investigation C
Communication A
Application
7. What can happen when a substance absorbs energy?
(3.2) K/U
(a) Electrons in the substance transition from their
ground state to an excited state.
(b) Excess energy is released by the emission of light
of various wavelengths.
(c) Electrons are emitted from the surface of the
material.
(d) all of the above
8. Which of the following is included in quantum theory? (3.1) K/U
(a) Light has properties of waves.
(b) Light has properties of particles.
(c) Particles have properties of waves.
(d) all of the above
9. According to Heisenberg’s uncertainty principle,
(a) atomic orbitals can be described by a set of
quantum numbers
(b) electrons travel in distinct paths called orbits
(c) it is impossible to know the exact position and
speed of an electron at the same time
(d) in a given atom, no 2 electrons can have the same
set of four quantum numbers (3.3, 3.4) K/U
10. What is the maximum number of electrons that can
occupy the second energy level? (3.4) K/U
(a) 1
(b) 2
(c) 4
(d) 8
11. Which of the following orbitals is the highest in
energy? (3.4) K/U
(a) 3p
(b) 3d
(c) 4s
(d) 4p
12. Which of the following orbital designations is
incorrect? (3.4) K/U
(a) 1p
(c) 3f
(b) 2d
(d) all of the above
13. Which is the electron configuration for the element
gallium? (3.5) K/U
(a) 1s22s22p63s23p64s23d54p6
(b) 1s22s22p63s23p64s23d10
(c) 1s22s22p63s23p63d104s24p1
(d) 1s21p62s22p63s23p64s24p4
NEL
5/16/12 4:46 PM
14. Which of the following correctly matches the group
name with the number of valence electrons? (3.5) K/U
(a) noble gases — 3
(b) alkali metals — 4
(c) halogens — 5
(d) alkaline earth metals — 2
15. What is the basis of ionic bonding? (4.1) K/U
(a) the equal sharing of bonding electrons
(b) the transfer of an electron from a non-metal to a
metal
(c) the electrostatic attraction between oppositely
charged ions
(d) the unequal sharing of bonding electrons
16. Which of the following describes how an atom can
obtain an octet of electrons? (4.1) K/U
(a) by gaining electrons until it has 8 valence
electrons
(b) by losing electrons until it has 8 valence electrons
(c) by sharing electrons until it has 8 valence
electrons
(d) all of the above
17. A fluoride ion has
(a) 9 protons and 10 electrons
(b) 9 protons and 9 electrons
(c) 10 protons and 9 electrons
(d) 9 protons and 8 electrons (4.1) K/U
18. Which of the following contains a coordinate covalent
bond? (4.1) K/U
(a) NH41
(b) Cl2
(c) H2O
(d) NaCl
19. How many electrons are in a typical calcium ion?
(4.1) K/U
(a) 2
(b) 18
(c) 20
(d) 22
20. In reactions with non-metals, metals tend to
(a) gain electrons and become negative ions
(b) gain electrons and become positive ions
(c) lose electrons and become negative ions
(d) lose electrons and become positive ions (4.1) K/U
21. Which of the following pairs of elements would most
likely form a covalent compound? (4.1) K/U
(a) aluminum and silicon
(b) calcium and oxygen
(c) hydrogen and sulfur
(d) calcium and potassium
NEL
436900_Chem_CH04_P255-279.indd 273
22. Which of the following molecules has a triple bond?
(4.2) K/U
(a) NH3
(b) HF
(c) CO2
(d) C2H2
23. What is the shape of a molecule of carbon
tetrachloride, CCl4? (4.2) K/U
(a) linear
(b) trigonal planar
(c) tetrahedral
(d) octahedral
24. How many lone electron pairs does the Lewis
structure for the ammonia molecule have on the
central atom? (4.2) K/U
(a) 0
(b) 1
(c) 2
(d) 3
25. In a polar covalent bond, valence electrons are
(a) equally shared between atoms
(b) unequally shared between atoms
(c) transferred from a metal to a non-metal
(d) transferred from a non-metal to a metal (4.3) K/U
26. Which element has the highest electronegativity?
(4.3) K/U
(a) I
(b) Br
(c) Cl
(d) F
27. If the difference in the electronegativity between 2 atoms is less than 0.5, then the bond between them is
(a) polar covalent
(b) non-polar covalent
(c) ionic
(d) none of the above (4.3) K/U
28. What type of orbital hybridization is present in a
water molecule? (4.6) K/U
(a) sp
(b) sp2
(c) sp3
(d) sp3d
29. Hydrogen bonding is the strong intermolecular force
between hydrogen atoms and
(a) oxygen atoms
(b) fluorine atoms
(c) nitrogen atoms
(d) all of the above (4.7) K/U
Unit 2 Review 273
5/3/12 9:55 AM
Indicate whether each statement is true or false. If you think
the statement is false, rewrite it to make it true.
30. A proton is a negatively charged subatomic particle.
(3.1) K/U
31. Radiation is the travel of particles or energy waves
through a medium or in space. (3.1) K/U
32. Electrons are attracted to protons but repel each
other. (3.1) K/U
33. The atomic number of an atom is the sum of the
protons and neutrons in the nucleus. (3.1) K/U
34. The nucleus accounts for most of an atom’s mass. (3.1) K/U
35. Each element has a unique number of protons. (3.1) K/U
36. A quantum is a packet of energy. (3.1) K/U
37. If an electron emits a photon, it can drop to a lower
energy level. (3.2) K/U
38. The highest energy state for an atom is its ground
state. (3.2) K/U
39. Spectroscopy of excited gaseous elements led to the
discovery of line spectra. (3.2) K/U
40. Blackbody radiation is the energy that would be
emitted from an ideal blackbody. (3.1) K/U
41. Quantum theory is the theory that energy can exist
only in discrete amounts. (3.3) K/U
42. An orbit is the region around the nucleus where there
is a high probability of finding an electron. (3.3) K/U
43. The principal quantum number indicates the main
energy level of an electron in an atom. (3.4) K/U
44. The electron configuration for the element calcium is
[Ar]4s1. (3.5) K/U
45. A magnesium atom has 3 valence electrons. (3.5) K/U
46. A lithium atom has 2 electrons in its second energy
level. (3.5) K/U
47. Ionic bonds are formed by a transfer of electrons
from metal atoms to non-metal atoms. (4.1) K/U
48. The bond between 2 chlorine atoms is ionic. (4.1) K/U
49. Lewis structures show the arrangement of electrons in
a molecule. (4.1) K/U
50. Ionic compounds are composed of 2 or more non-metal ions. (4.1) K/U
51. A triple bond contains 3 shared pairs of electrons.
(4.2) K/U
52. The Lewis structure for a water molecule has 1 lone
pair of electrons on the central atom. (4.2) K/U
53. The valence shell electron-pair repulsion (VSEPR)
theory describes how atomic orbitals and hybrid
orbitals overlap to form a new orbital with a pair of
opposite-spin electrons. (4.2) K/U
54. The polarity of a bond decreases as the
electronegativity difference increases. (4.3) K/U
274 Unit 2 • Structure and Properties of Matter
436900_Chem_CH04_P255-279.indd 274
55. The end-to-end overlap of orbitals forms a pi bond.
(4.6) K/U
56. Intramolecular forces occur between molecules. (4.7) K/U
Match the scientist on the left with the most appropriate
discovery on the right.
57. (a) Max Planck
(b) Albert Einstein
(c) Louis de Broglie
(d) Niels Bohr
(e) Wolfgang Pauli
(f) Werner
Heisenberg
(g) Erwin
Schrödinger
(h) James Chadwick
(i) J.J. Thomson
(j) Ernest
Rutherford
(i)
i dea that energy
from a blackbody is
quantized
(ii) discovery of the
neutron
(iii) discovery of the
nucleus
(iv) idea that the
energy of electrons
is quantized
(v) the photoelectric
effect
(vi) discovery of the
electron
(vii) the exclusion
principle
(viii)equation describing
the energy and
location of an
electron in a
hydrogen atom
(ix) uncertainty
principle
(x) quantum theory
(3.1, 3.2, 3.3) K/U
Match the term on the left with the most appropriate
description on the right.
58. (a) linear
(b) trigonal planar
(c) tetrahedral
(d) octahedral
(i) h
as four bond angles
of 90° in a plane and
two bonds at 90° to
the plane
(ii) has a bond angle of
180°
(iii) has bond angles of
109.5°, each equally
positioned in four
locations around the
central atom
(iv) has bond angles of
120° and all of the
atoms are found in the
same plane (4.2) K/U
NEL
5/3/12 9:55 AM
Understanding
Write a short answer to each question.
59. Explain J.J. Thomson’s “blueberry muffin model” of
the atom. (3.1) K/U
60. What was Robert Millikan’s contribution to atomic
theory? (3.1) K/U
61. Explain how and why the results of Rutherford’s gold
foil experiment differed from his expectations. (3.1) K/U
62. What was the problem with the Rutherford atomic
model? (3.1) K/U
63. How do isotopes of a given element differ? How are
they similar? (3.1) K/U
64. How do the numbers of protons and electrons in a
neutral atom compare? (3.1) K/U
65. What is the relationship between an isotope and a
radioisotope? (3.1) K/U
66. What part of Dalton’s atomic theory did Thomson
disprove with the discovery of electrons? (3.1) K/U
67. According to Dalton’s atomic theory, all atoms of
a given element are identical in mass and other
properties. Is this correct? Explain. (3.1) K/U
68. The three mass numbers of the three isotopes of neon
are 20, 21, and 22. How many neutrons does each
isotope have? (3.1) K/U
69. What is a cathode ray tube? (3.1) K/U
70. How does the mass of the nucleus compare with the
mass of the rest of the atom? (3.1) K/U
71. Name two phenomena that support the concept that
light is a packet of energy. (3.1) K/U
72. Why was the Bohr atomic model, although incorrect,
a significant contribution to atomic theory? (3.2) K/U
73. How are scientists able to determine what elements
are present in distant stars? (3.2) K/U
74. Draw an illustration that describes the relationships
among emission spectra, line spectra, and continuous
spectra. (3.2) K/U C
75. What conclusions did scientists draw from each of the
following observations? (3.1, 3.2) K/U
(a) An atom emits a specific set of frequencies of
light when it is excited by thermal energy or
electricity.
(b) A beam of electrons is deflected by an electric
field toward a positively charged plate.
76. What is an atomic orbital? (3.3) K/U
77. Why is it impossible to determine both the exact
location and the velocity of an electron? (3.3) K/U
78. What information is given by the solutions to
Schrödinger’s equation? (3.3) K/U
NEL
436900_Chem_CH04_P255-279.indd 275
79. Using n to represent the principal energy level
number, write equations that show the relationship
between
(a) the principal energy level number and the
number of sublevels (subshells)
(b) the principal energy level number and the
number of orbitals
(c) the principal energy level number and the
maximum number of electrons in an energy level
(3.4) K/U T/I
80. Explain why the following set of quantum numbers is
not possible: n 5 3; l 5 3; ml 5 0 (3.4) K/U
81. What is the maximum number of electrons that can
have the same
(a) n, l, ml, and ms quantum numbers?
(b) n, l, and ml quantum numbers?
(c) n and l quantum numbers? (3.4) K/U
82. Identify the elements with these electron
configurations: (3.5) K/U
(a) 1s22s22p63s23p63d104s24p6
(b) 1s22s22p63s2
(c) 1s22s22p63s23p63d104s24p64d75s1
(d) 1s22s22p63s23p6
83. An orbital representation uses circles or lines to
represent atomic orbitals, and arrows to represent
electrons. The direction of the arrow (up or
down) represents the electron spin direction. For
example, the orbital representation of a 3p sublevel
consists of three lines or circles with each line
or circle representing an orbital. Draw an orbital
representation of a 3p sublevel that
(a) shows a violation of Hund’s rule
(b) shows a violation of the Pauli exclusion principle
(c) is a correct representation of a 3p sublevel with
3 electrons (3.5) K/U C
84. Write the name of the element that fits each
description. (3.5) K/U
(a) has 5 valence electrons in its third energy level
(b) noble gas with 2 valence electrons
(c) non-metal with 1 valence electron
(d) semiconductor with 3 valence electrons
85. State the number of valence electrons in an atom of
each element below. (3.5) K/U
(a) aluminum
(b) oxygen
(c) helium
(d) bromine
Unit 2 Review 275
5/3/12 9:55 AM
86. The term “isoelectronic” refers to entities that have
the same electron configuration. For example, the
magnesium ion, Mg21, and the fluoride ion, F2, are
isoelectronic. Write the formulas for two other atoms
or ions that are isoelectronic with the magnesium and
fluoride ions. (3.5) K/U
87. Why are there no transition elements in periods 1, 2,
and 3? (3.5) K/U
88. Write the electron configuration of
(a) the element with the highest electronegativity
(b) the non-metal element in Group 4A
(c) the transition element with the lowest atomic
number
(d) the noble gas that has 2 valence electrons (3.5) K/U
89. How many electrons are transferred from the
beryllium atom to the sulfur atom when they form an
ionic bond? (4.1) K/U
90. Explain why a fluoride ion is larger than a fluorine
atom. (4.1) K/U
91. Indicate whether each of the following atoms is more
likely to form a cation (a positively charged ion) or an
anion (a negatively charged ion): (4.1) K/U
(a) calcium
(b) chlorine
(c) lithium
(d) oxygen
92. Indicate the most likely number of electrons each of
the following atoms will gain or lose in forming ionic
bonds: (4.1) K/U
(a) sodium
(b) phosphorus
(c) chlorine
(d) strontium
93. Draw a Venn diagram to compare and contrast ionic
bonding and covalent bonding. (4.1) K/U T/I C
94. Why are ionic compounds electrically neutral? (4.1) K/U
95. Consider the following Lewis structure, where E is an
unknown element. What are some possible identities
for element E? (4.2) K/U
H
H
H
E
109.5°
H
96. What is the difference between a bonded electron pair
and a lone pair? (4.2) K/U
97. What is electron-pair repulsion? (4.2) K/U
276 Unit 2 • Structure and Properties of Matter
436900_Chem_CH04_P255-279.indd 276
98.How does electron-pair repulsion affect the shape of a
molecule? (4.2) K/U
99. The molecule with the chemical formula
HOOCCH2COCH3 is a 4-carbon chain with
1 oxygen atom (carbonyl group) double-bonded
to carbon 3 and 1 oxygen atom (carboxylic acid)
double-bonded to carbon 1. Use the VSEPR theory
to describe the geometry around each of the carbon
atoms. (4.2) T/I
100. What happens when the electronegativity difference
between 2 atoms is very large? (4.3) K/U
101. Place the following elements in order of increasing
electronegativity: K, Br, Na, O, S. (4.3) K/U
102. Choose the element in each of the following pairs that
has the highest electronegativity: (4.3) K/U
(a) K and Ca
(b) O and F
(c) S and Si
(d) Ga and Ge
103. The electronegativity of the element hydrogen is the
same as that of the element phosphorus, greater than
that of the element boron, and less than that of the
element carbon. List the following bonds in order of
decreasing polarity: P–H, O–H, N–H, F–H, C–H.
(4.3) K/U
104. Predict the type of bond—ionic, non-polar covalent,
or polar covalent—that forms between the following
pairs of elements: (4.3) K/U
(a) Rb and Cl
(b) S and S
(c) C and F
(d) Ba and S
(e) N and P
(f) B and H
105. Write Lewis structures, and predict the molecular
structures of oxygen dichloride, OCl2; krypton
difluoride, KrF2; beryllium hydride, BeH2; sulfur
dioxide, SO2; sulfur trioxide, SO3; nitrogen trifluoride,
NF3; iodine trifluoride, IF3; tetrafluoromethane, CF4;
selenium tetrafluoride, SeF4; krypton tetrafluoride,
KrF4; iodine pentafluoride, IF5; and arsenic
pentafluoride, AsF5. Which of these molecules are
polar? (4.1, 4.2, 4.5) K/U C
106. (a) Determine the electron configuration of each of
the following atoms:
(i) P (iii) Br
(ii) S (iv) Si
(b) Use your answers from (a) to draw the orbital
diagram of the valence electrons for each of the
above atoms. (4.6) K/U C
NEL
5/3/12 11:18 AM
107. For each of the atoms in Question 106, determine the
orbital it would use to bond with hydrogen atoms to
form the following compounds: (4.6) K/U
(a) PH3
(b) H2S
(c) HBr
(d) SiH4
108. Each of the following atoms reacts with hydrogen: (i) boron; (ii) nitrogen; (iii) carbon; and (iv) fluorine. (4.6) K/U T/I C
(a) Write the electron configuration for each atom.
(b) Draw the orbital diagrams, showing the valence
electrons for each atom.
(c) Determine whether any electrons need to be
promoted. If so, draw a new orbital diagram
showing the excited-state atom.
(d) Hybridize the orbitals as needed. Draw the orbital
diagrams, showing the hybrid orbitals.
(e) How many half-empty orbitals does each atom
have? How many orbitals are available for
bonding?
(f) State the orbital each atom would use to form a
sigma bond with a hydrogen atom.
(g) Draw the resulting molecule.
109. Predict the hybridization of each atom, and describe
the three-dimensional structure of each of the
following molecules: (4.6) K/U T/I
(a) BeCl2
(b) H2S
(c) H2CO
(d) SiF4
110. Which liquid would have the greater surface
tension: butane, CH3CH2CH2CH3, or 1-propanol,
CH3CH2CH2OH? Why? (4.7) K/U
111. Discuss the similarities and differences between
(a) polar bonds and hydrogen bonds
(b) dipole–dipole interactions and London dispersion
forces (4.7) K/U T/I
112. Explain how the properties of each solid allow it to be
used as described: (4.8) K/U A
(a) Copper is the most common metal used in
electrical wires.
(b) Diamonds are used in industry as abrasives and
drill tips.
(c) Liquid nitrogen (boiling point 2196 °C) is used
as a refrigerant.
NEL
436900_Chem_CH04_P255-279.indd 277
113. Explain the difference between intramolecular forces
and intermolecular forces. (4.8) K/U
114. (a) Characterize each of the following forces as
intramolecular or intermolecular:
(i) van der Waals
(ii) London dispersion
(iii)dipole–dipole
(iv)hydrogen bonds
(v) covalent bonds
(b) Arrange the forces in (a) from strongest to
weakest. (4.8) K/U
115. Why does molten potassium chloride, KCl(l), conduct
electricity even though solid potassium chloride does
not? (4.8) K/U A
116. Draw a chart showing the similarities and differences
between
(a) metallic and ionic bonds
(b) network solids and covalent molecules (4.8) K/U C
117. What type of substance is each of the following? (4.8) K/U T/I
(a) Gallium crystals are shiny and silver-coloured.
They are good conductors of electricity. Gal­lium
metal melts at 29.8 °C.
(b) This compound has a very high melting point,
is hard and brittle, and conducts electricity as a
liquid but not as a solid.
(c) Liquid tin(IV) chloride does not conduct
electricity. It forms crystals that are soft, and it
has a melting point of 233 °C.
(d) Paradichlorobenzene is one of the main
ingredients in mothballs. It has a melting point of
54 °C and crushes fairly easily.
(e) Mica is an unusual rock that cleaves (breaks) in
very thin layers. It has a melting point of 1378 °C. It is chemically unreactive, and is stable
when exposed to electricity, light, moisture, and
extreme temperatures.
(f) Some semiconductors are made of the transition
metal boron. Boron is very hard and has a
melting point of 2349 °C.
(g) Hydrargyrum is a name once used for one of
the elements. It is a shiny silver liquid at room
temperature that conducts electricity very well.
118. How could you tell experimentally whether titanium
dioxide, TiO2, is an ionic solid or a network solid?
(4.8) K/U T/I
Unit 2 Review 277
5/3/12 9:55 AM
119. What type of solid does each of the following
substances form? (4.8) K/U T/I
(a) CO2
(g) KBr
(b) SiO2 (h) H2O
(i) NaOH
(c) Si (d) CH4 (j) U
(k) CaCO3
(e) Ru (f) I2 (l) PH3
120. Identify the four substances in Table 1 as ionic,
network, metallic, or molecular solids. (4.8) K/U
T/I
Table 1
Compound
Conducts
electricity
as a solid
Other properties
diborane, B2H6
no
gas at 25 8C
silicon dioxide, SiO2
no
high melting point
cesium iodide, CsI
no
aqueous solution
conducts electricity
tungsten, W
yes
high melting point
121. Briefly describe lattice structures. (4.8) K/U
122. Explain why ionic compounds are brittle. (4.8) K/U
123. Indicate whether each of the following is a property
of ionic compounds or covalent compounds: (4.8) K/U
(a) form crystal lattices
(b) low melting and boiling points
(c) tend to be brittle solids
(d) tend to be soluble in water
(e) tend to have low solubility in water
(f) have high melting and boiling points
125. Using what you know about the structure of metals,
covalent crystals and ionic substances, and the
quantization of light, explain why the photoelectric
effect is best demonstrated using metal. (3.1, 4.8) K/U A
126. Water is an unusual molecule. It has high melting
and boiling points that are uncharacteristic and can
dissolve many ionic compounds. As a result, it is
the solvent of life. Biological life without water is
difficult to imagine. Indeed, recent evidence of liquid
water on Mars has sparked new interest in whether
life has existed there in the past or currently exists.
Based on your understanding of the structure of
water predicted by VSEPR theory, suggest why water’s
structure is ultimately responsible for its remarkable
properties. (4.2) K/U T/I A
127. Biacetyl and acetoin are added to margarine to make it
taste more like butter. The structures of both compound s
are shown in Figure 2. (4.3, 4.5, 4.6) T/I C A
CH3
O
O
C
C
O
CH3
CH3
CH
C
CH3
OH
biacetyl
acetoin
Figure 2
(a) Draw the Lewis structure for each compound and
indicate the hybridization of the carbon atoms.
(b) Predict values for all C–C–O bond angles. (c) How many sigma bonds and how many pi bonds
are there in biacetyl and acetoin molecules?
128. Illustrate the bonding using diagrams of the orbitals
for each of the following. Show the bonding orbitals
formed. (4.6) K/U T/I C
(a) HF
(d) NF3
Analysis and Application
(b) F2
(e) C2Cl4
(c)
BCl
3
124. Figure 1 shows how the electron clouds of
2 hydrogen atoms interact as a covalent bond 129. Water is an extremely effective solvent for dissolving
forms. (4.1) K/U T/I C
polar and ionic compounds. To work as a cleaning
agent, the water first has to reach the “dirt.” This
(a) Draw a similar diagram showing how hydrogen
can become a problem. The same property of water
and chlorine atoms will react to form a covalent
that makes it such a good solvent—its ability to
bond. Show the attractive and repulsive forces.
form strong dipole–dipole interactions—also makes
(b) Draw a similar diagram showing how 2 fluorine
it difficult to get into the small spaces where dirt
atoms will react.
lingers. Water would rather interact with other water
molecules than leave its neighbouring molecules
in search of dirt. This tendency to be attracted to
Chemistry 12
other similar molecules is called surface tension.
+
+
+
+
0176504524
Water’s surface tension is extremely high. Surface
tension is the enemy of cleaning systems. Special
C04-F154-OC12USB
FN
H atom
H atom
H
molecule
2
CrowleArt Groupchemicals called surfactants are added to detergents
CO
specifically to lower the surface tension of water so it
Figure 1
Deborah Crowle
can penetrate small spaces and dislodge and dissolve
1st pass
Pass
Approved
278 Unit 2 • Structure and Properties of Matter
NEL
Not Approved
436900_Chem_CH04_P255-279.indd 278
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dirt. If you were asked to design a surfactant, what
chemical properties would you want your surfactant
molecule to have? How would you explain to a
consumer how your surfactant works? (4.7) T/I C A
130. Hydrogen peroxide (H2O2) is a syrupy liquid with
a relatively low vapour pressure and a boiling point
of 152.2 °C. Explain the differences of these physical
properties from those of water. (4.7) K/U A
131. Hydrogen bonds greatly affect the properties of water.
In a format of your choice, describe how the world
around us would be different if water did not have
hydrogen bonds. (4.7) K/U T/I C A
132. The element selenium is a semiconductor used in
photocopiers. What type of semiconductor would be
formed if a small amount of indium impurity were
added to pure selenium? (4.8) T/I A
Evaluation
133. Evaluate the benefits to society of nanoparticles used in medicine. What impact would the widespread
use of nanoparticles have on the environment? (3.7) T/I C A
134. Cyclotrons, synchrotrons, and linear accelerators have
been used to discover new subatomic particles. What
social benefits are associated with these discoveries?
(3.7) T/I C A
135. Evaluate the cost and environmental impact of several
types of light bulbs. Include the advantages and
disadvantages of each type. (3.7) T/I C A
Reflect on Your Learning
136. Many of the concepts in this unit are abstract.
Describe some of the strategies you have used to
understand these concepts. C
137. What information in this unit did you find most
interesting? Why? What information did you find
least interesting? Why? C
138. Think about what you already knew about atomic
structure and bonding before beginning this unit.
What misconceptions did you have? Where did they come from? How has working through this unit helped you identify and correct your
misconceptions? C
139. How would you explain to a friend or family member
who does not have any chemistry training what you
learned in this unit? C
WEB LINK
Research
140. Many specialized materials have been created on the
basis of scientific research into the structure of matter
and chemical bonding. Research disposable diapers. T/I
C
(a) What properties of disposable diapers enable
them to hold so much liquid?
(b) What impact has the widespread use of such
diapers had on the environment?
141. An amorphous solid has no specific arrangement of
its atoms or ions. Tar and wax are amorphous solids.
Glass is also an amorphous solid. Most glass contains
silicon dioxide, SiO2, as the main ingredient. C A
(a) Based on its chemical structure, is silicon dioxide
an ionic or covalent compound?
(b) Research the properties of glass. Do the
properties of glass more closely match those of
an ionic compound or a covalent compound?
Discuss the structure and properties of glass. Give
details to support your opinion on whether glass
is an ionic or covalent compound.
142.Technological devices that are based on the principles
of atomic and molecular structures can have societal
benefits and costs. Discuss a technology that is based
on the principles of atomic emission. Describe the
social and economic implications of the technology.
Share your findings in a written report. A C
143.The colours observed in fireworks displays are
produced by heating metal salts. Use Internet
resources to determine how salts are used in fireworks
displays and the processes that cause these salts to
emit light. Create a poster or electronic slideshow to
share your findings. C A
144. What is known about the atom is due to contributions
from several disciplines. Describe the contributions to
atomic theory of at least eight philosophers, chemists,
physicists, and mathematicians, choosing two people
from each category. Prepare a timeline to display what
you learned. C A
145. (a) What types of metals are used in dental amalgams?
What properties of these metals allow them to be
used for this purpose?
(b) What metals are used to make coins? What are
the properties of these metals? Why are they used
instead of other metals? C A
146. Hair is composed mainly of a protein called keratin.
What types of chemical bonds are present in hair?
How do chemical processes such as perming and
colouring affect these bonds? Use Internet resources to
answer these questions. Prepare an advertisement or
an electronic slideshow to share your findings. T/I A
147. Choose a radioisotope that is used in the diagnosis
of disease. Explain what care must be taken in the
storage, use, and disposal of this material. Prepare a
workplace training brochure from the information
you find. T/I A
A
NEL
436900_Chem_CH04_P255-279.indd 279
Unit 2 Review 279
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