TEACHER GUIDE AND ANSWERS
Study Guide: The Structure of the Atom
Early Ideas About Matter
1. false
2. true
3. true
4. true
5. false
6. false
7. true
8. true
9. false
10. true
Defining the Atom
1. c
2. a
3. b
4. Drawing should look like a ball of chocolate chip
cookie dough. The chocolate chips should be
labeled with negative charge or as electrons. The
dough should be labeled as evenly distributed
positive charges.
5. Drawing should look like a peach with a pit. The
pit should be labeled nucleus and should include
labeled protons and neutrons. The outer circle of
the peach should be labeled electrons.
Particle
Symbol
Location
Relativ
e
Charge
Relative
mass
6. Proton
p+
In the nucleus
1+
1
7. Neutron
n0
In the nucleus
0
1
8.
Electron
e−
In the space
surrounding
the nucleus
1−
1/1840
How Atoms Differ
1. false
2. true
3. true
4. true
5. false
6. 82 protons; 82 electrons
7. 8 protons
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
30
85
104 protons; 104 electrons
84 protons; 84 electrons
102 protons; 102 electrons
19 protons, 19 electrons, 20neutrons
14 protons, 14 electrons, 14 neutrons
19 protons, 19 electrons, 21 neutrons
51 protons, 51 electrons, 72 neutrons
The two isotopes with atomic number 19 are both
isotopes of potassium.
22
Ne
18. 10
19.
4
2
20.
133
55
Cs
21.
234
92
U
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
Ne
mass number
atomic number
d
a
d
76
Nb
190.2
atomic mass units
osmium: 76 protons, 76 electrons; niobium:
41 protons, 41 electrons.
32. Mass contribution = (mass)(percent abundance)
63
X: (62.930 amu)(69.17%) = 43.53 amu
65
X: (64.928 amu)(30.83%) = 20.02 amu
Atomic mass of X = 43.53 amu + 20.02 amu =
63.55 amu
The element is copper.
33. Mass contribution = (mass)(percent abundance)
35
X: (34.969 amu)(75.77%) = 26.50 amu
37
X: (36.966 amu)(24.23%) = 8.957 amu
Atomic mass of X = 26.50 amu + 8.957 amu =
35.46 amu
The element is chlorine.
TEACHER GUIDE AND ANSWERS
Unstable Nuclei and Radioactive Decay
1. c
2. a
3. d
4. b
5. the positive plate, because beta particles are
negatively charged
6. Gamma rays have no charge.
7. The beta particles have less mass than the alpha
particles and ar more greatly affected by the
electric field.
Radiation Composition Symb Mass Char
Type
ol
(amu) ge
Helium
nuclei, or
8. Alpha
alpha
particles
9.
10.
Beta
Gamma
4
2
He
Electrons,
beta
particles
0
−1
High-energy
electromagn
etic radiation
0
0
4
2+
β
1/1840 1−
γ
0
0