CHAPTER 1
ANSWER KEY
BLM 1-1, Interpreting an MSDS/Skill
Builder
Goal: Students demonstrate their understanding of the
information on a chemical label and a Material Safety Data
Sheet (MSDS) .
Answers
1. (a) The name of the substance is cupric sulfate
pentahydrate. The chemical formula is
CuSO4·5H2O.
(b) The substance is potentially toxic either by
absorption or by inhalation.
(c) To avoid exposure, students should wear safety
glasses, an apron, and gloves. Although not
stated, proper ventilation is essential. The dust
should not be inhaled.
(d) Excess amounts of this chemical should be
deposited in a labelled waste container.
(e) The teacher should be informed immediately. The
teacher should immediately contact poison
control or medical personnel to find out how to
proceed. It is likely that vomiting will need to be
induced.
2. Note: For this question, search the Internet to find
MSDS sheets to give your students. Use a search
engine to search for an MSDS for any chemical by
typing in “MSDS” and the name of the chemical. You
may wish to provide all students with copies of the
same MSDS, or provide a variety of MSDS sheets.
Answers are given below for an MSDS for strontium
nitrate, Sr(NO3)2.
(a) The name of the substance is strontium nitrate.
The chemical formula is Sr(NO3)2.
(b) The substance is slightly dangerous to your
health. It may cause irritation of the skin, eyes,
lungs, or gastrointestinal tract. Long-term
exposure may result in liver, kidney, bone, blood,
and nerve damage.
(c) Inhalation of the dust from the chemical should
be avoided. Students should wear gloves, goggles,
and aprons. The substance must not be mixed
with a reducing agent, because this could cause a
fire.
(d) In the event of a fire, firefighters should wear full
protective clothing and a self-contained breathing
apparatus.
(e) All sources of ignition should be removed and
proper ventilation should be initiated. Cleaning
precautions should be taken to minimize or avoid
dispersion of dust into the air. Waste should be
sent to an appropriate hazardous waste facility.
(f) The material should be stored in a cool, dry
location.
BLM 1-2, Anatomy of an Atom/
Information Handout
Answers
not applicable
BLM 1-3, Periodic Table/Information
Handout
Answers
not applicable
BLM 1-4, Periodic Table Scavenger
Hunt/Skill Builder
Goal: Students demonstrate their understanding of the
periodic table.
Answers
1. Answers are in boldface.
The element called chromium has an atomic number
of 24. Its symbol is Cr. When an atom of this element
has a mass number of 52, the atom contains 24
protons and 28 neutrons. The most common ion
charge of this element is 3+.
2. (a) niobium, Nb
(b) bromine, Br
(c) francium, Fr
(d) technetium, Tc
(e) tellurium, Te
(f) beryllium, Be
(g) xenon, Xe
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be held responsible for content if any revisions, additions, or deletions are made to this page.
CHAPTER 1
ANSWER KEY
3. Answers are in boldface.
Name of
element
Symbol of
isotope
Atomic
number
Atomic
mass
Number of
protons
Number of
electrons
Number of
neutrons
silicon
28
14
Si
14
28
14
14
14
oxygen
16
8
O
8
16
8
8
8
chromium
52
24
Cr
24
52
24
24
28
sodium
23
11
Na
11
23
11
11
12
aluminium
27
13
Al
13
27
13
13
14
potassium
39
19
K
19
39
19
19
20
beryllium
9
4
Be
4
9
4
4
5
4.
5. (a) neon –20
(b) sodium –23
(c) carbon 12
6. (a)
b)
(c)
7. The bold “staircase” line in the periodic table
separates the metals (left) from the non-metals (right).
8. Halogens may be gases, liquids, or solids at room
temperature and pressure. Alkali metals are all shiny
solids. Alkali metal atoms have one valence electron.
Halogen atoms have seven valence electrons. Alkali
metals are found in group 1 of the periodic table.
Halogens are found in group 17 of the periodic table.
Copyright © 2004 McGraw-Hill Ryerson Limited. Permission to edit and reproduce this page is granted to the purchaser for use in her/his classroom. McGraw-Hill Ryerson shall not
be held responsible for content if any revisions, additions, or deletions are made to this page.
CHAPTER 1
ANSWER KEY
Answers
BLM 1-5, Electron Dot Diagrams/Skill
Builder
1. Answers are in bold face.
Goal: Students demonstrate their understanding of energy
levels and practise drawing electron dot diagrams.
Name of element
Period number
Group number
Number of energy
levels
Number of valence
electrons
hydrogen
1
1
1
1
aluminium
3
13
3
3
oxygen
2
16
2
6
strontium
5
2
5
2
silicon
3
14
3
4
barium
6
2
6
2
2.
Name of element
Energy level diagram
Electron dot diagram
carbon
oxygen
lithium
chlorine
Copyright © 2004 McGraw-Hill Ryerson Limited. Permission to edit and reproduce this page is granted to the purchaser for use in her/his classroom. McGraw-Hill Ryerson shall not
be held responsible for content if any revisions, additions, or deletions are made to this page.
CHAPTER 1
ANSWER KEY
Name of element
Energy level diagram
Electron dot diagram
magnesium
phosphorus
BLM 1-6, Drawing Electron Dot Diagrams/
Science Inquiry
BLM 1-7, Isotopes and Ions/
Reinforcement
Goal: Students practise drawing electron dot diagrams.
Goal: Students demonstrate their understanding of
isotopes and practise identifying and naming ions.
Answers
Answers
Answers to the questions for Find Out Activity: Drawing
Electron Dot Diagrams are provided in the
SCIENCEFOCUS 10 Teacher’s Resource.
1. Answers are in boldface in the table below.
Name of ion
Symbol
Number of
protons
Number of
electrons
Net charge
lithium ion
Li+
3
2
1+
potassium ion
K+
19
18
1+
12
10
2+
magnesium ion
2+
Mg
chloride ion
Cl–
17
18
1–
fluoride ion
–
9
10
1–
2–
8
10
2–
iodide ion
I
–
53
54
1–
scandium ion
Sc3+
21
18
3+
oxide ion
sulfide ion
selenide ion
nitride ion
aluminium ion
F
O
2–
16
18
2–
2–
34
36
2–
3–
7
10
3–
3+
13
10
3+
4–
S
Se
N
Al
carbide ion
C
6
10
4–
calcium ion
Ca2+
20
18
2+
15
18
3–
phosphide ion
P
3–
Copyright © 2004 McGraw-Hill Ryerson Limited. Permission to edit and reproduce this page is granted to the purchaser for use in her/his classroom. McGraw-Hill Ryerson shall not
be held responsible for content if any revisions, additions, or deletions are made to this page.
CHAPTER 1
ANSWER KEY
2. Answers are in boldface.
Name of isotope
Symbol
Mass number
Number of
protons
Number of
neutrons
hydrogen-3 (tritium)
3
1
H
3
1
2
scandium-49
49
21
Sc
49
21
28
cobalt-60
60
27
Co
60
27
33
nitrogen-15
15
7
N
15
7
8
uranium-238
238
92
U
238
92
146
iodine-129
129
53
I
129
53
76
barium-135
135
56
Ba
135
56
79
strontium-86
86
38
Sr
86
38
48
oxygen-18
18
8
O
18
8
10
carbon-14
14
6
C
14
6
8
BLM 1-8, Ionic or Covalent: Track Those
Electrons/Science Inquiry
Goal: Students use rings and diagrams to model the
formation of ionic compounds and covalent compounds.
Answers
Answers to the questions for Investigation 1-A: Ionic or
Covalent: Track Those Electrons are provided in the
SCIENCEFOCUS 10 Teacher’s Resource.
BLM 1-9, Chapter 1 Test/Assessment
Goal: Students demonstrate their understanding of the
information presented in Chapter 1.
Answers
1. T
2. T
3. F: Rutherford’s model of the atom was rejected
because it could not explain emission spectra and
the stability of atoms.
4. F: Bromine and mercury are the only elements in the
periodic table that are liquids at room
temperature.
5. F: All atoms of any one element must have the same
number of protons.
6. (c)
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
(a)
(d)
(e)
(b)
law of conservation of mass
isotope
energy level
ion
covalent bond
(b)
(d)
(b)
(c)
(d)
(c)
(a)
(b)
(b)
(d)
Thomson’s model had electrons embedded within a
sphere of positive charge. When Rutherford fired
alpha particles at gold foil, most of the electrons were
deflected only very slightly, while a very few bounced
back. These results suggested that the atom was
mostly empty space, with a dense, solid core.
Thomson’s model did allow for these results, so it was
rejected.
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be held responsible for content if any revisions, additions, or deletions are made to this page.
CHAPTER 1
ANSWER KEY
27. In an ionic bond, cations and anions are attracted
strongly because they are oppositely charged. In a
binary ionic compound, atoms of metal elements give
up electrons to atoms of non-metal elements, in such a
way that the atoms usually achieve a stable octet. In a
covalent bond, atoms of non-metal elements share
electrons, usually so that each atom achieves a stable
octet.
28.
29. (a) The oxygen isotopes have the same number of
electrons and the same number of protons. The
number of neutrons does not affect reactivity.
How elements form compounds is dictated
primarily by the valence electrons.
(b)
(c) Sodium oxide contains ionic bonds, while carbon
dioxide contains covalent bonds.
Copyright © 2004 McGraw-Hill Ryerson Limited. Permission to edit and reproduce this page is granted to the purchaser for use in her/his classroom. McGraw-Hill Ryerson shall not
be held responsible for content if any revisions, additions, or deletions are made to this page.