TUTORIAL 1
1
The diagram shows a model of an atom.
Which of the following is related to the model of
the atom?
A
B
C
D
2
Which of the following is not the direction of αparticles approach very close to the nucleus of
an atom?
6
An atom of an element has a nucleus
surrounded by particles.
Which of the following gives its structure?
Alpha - particles
Beta- particles
Gamma-particles
Light rays
In the Geiger-Marsden experiment , a narrow
beam of alpha particles was fired at a thin piece
of gold foil in a vacuum, Some particles were
scattered through large angles.
The result of the experiment provided evidence
for the existence of
A
B
C
D
4
5
The results of the Geiger-Marsden scattering
experiment provided evidence for the presence
of the nucleus within the atom.
What was scattered in this experiment?
A
B
C
D
3
Dalton
Thomson
Rutherford
Geiger-Marsden
A
B
C
D
uncharged atoms
unclear reactions
neutrons in the nucleus
a positively-charged nucleus
The diagram shows a narrow beam of αparticles is fired at a thin piece of gold foil.
What is the final direction of most of
α-particles?
7
1
Nucleus
Electrons and protons
Electrons and neutrons
Protons and neutrons
Electrons
Surrounded by
Neutrons
Protons
Electrons
Protons and
neutrons
Which of the following is a characteristic of a
neutron?
A Negatively charged
B Orbiting the nucleus
C Having 1.6 x 10-19 C of charge
D Having the same mass as the proton’s
mass
8
The nucleon number of an atom is the number
of ___________________________________
A
B
C
D
9
protons in nucleus
neutrons in nucleus
protons and electrons in nucleus
protons and neutrons in nucleus
A
B
C
D
11
A
1
1
H
B
4
2
He
C
7
3
Li
D
9
4
Be
What are isotopes?
A
B
C
Number of
protons
A
Z
A-Z
Z-A
Which of the following nuclides has equal
numbers of neutrons and protons?
D
Z
A
Z
A
15
Atoms which are radioactive
Atoms with too many neutrons
Atoms of the same element with different
numbers of protons
Atoms of the same element with different
numbers of neutrons
Which one of the following pairs of isotopes is
true?
An atom of lithium 3 electrons, 3 protons and 4
neutrons. Its nucleon number is
A
2
3
P and
A
C
E
C
8
4
R and 46 R
3
6
10
B
D
4
7
15
A nuclide is represented by 40
10 X .
How many neutrons and protons does each
nucleus contain?
Neutrons
Protons
A
B
C
D
12
14
How many neutrons and protons does one
atom of substance AZ X have in its nucleus?
Number of
neutrons
10
13
10
30
30
40
10
10
40
30
2
P
B
10
4
Q and 106 Q
D
12
18
S and 128 R
Deuterium 21 H and tritium 31 H , are two isotope
of hydrogen.
Compared to a deuterium atom, how many
protons, neutrons and electrons does a tritium
atom have?
A
B
C
D
Which of the following is true for a natural
atom?
Number of Number of Number of
protons
neutrons
electrons
A
12
12
5
B
8
14
14
C
16
7
16
D
14
15
16
2
10
Protons
Neutrons
Electrons
More
More
Same
Same
More
Same
More
More
Same
More
Same
Fewer
16
Three nuclei X, Y and Z have proton numbers
and nucleon numbers as shown in the table
below.
X
Y
Z
Proton number
43
43
44
Nucleon number
93
94
94
Which nuclei are isotopes of the same element?
(i)
A
B
C
D
17
X and Y only
X and Z only
Y and Z only
X, Y and Z
Explain why the alpha particle
changes direction.
............................................................
............................................................
............................................................
The diagram shows the ‘plum pudding’ model of
an atom.
............................................................
............................................................
............................................................
(ii)
(a) Scientists thought that the ‘pudding’ was
positively charged.
(i) Name the particles labelled A in the
diagram.
The diagram shows different
paths taken by alpha particles when
they were fired by Rutherford and
Marsden at the thin metal foil.
............................................................
(ii) Complete this sentence by choosing
the correct words from the box.
negatively charged
positively charged
uncharged
The boxes on the left show some observations
from the experiment.
The particles labelled A are
(b)
...........................................................
A new model of an atom was suggested
by Rutherford and Marsden.
They fired alpha particles at thin metal foil.
Alpha particles are positively charged.
In their model each atom has a nucleus.
The diagram below shows the path of an
alpha particle as it passes the nucleus of
an atom.
The boxes on the right give their explanations.
Draw a straight line from each observation to its
explanation.
One has been done for you.
3
Observation
some alpha
particles travel
along path Y
Explanation
because the
nucleus has a
very large
positive charge
and a large
mass
(i)
Which two of the atoms are from the
same elements.
………………………………………….
most of the
alpha particles
follow path X
because the
nucleus is very
small
(ii)
………………………………………….
Give a reason for your answer in a(i)
………………………………………….
………………………………………….
18
some alpha
particles
rebound
backwards
along path Z
because most
of each atom is
empty
space
very few alpha
particles follow
path
because the
nucleus is
positively
charged
………………………………………….
………………………………………….
(b) In the part of the 20th century some
scientists investigated the paths taken by
positively charged alpha particles into and
out of a very thin piece of gold foil. The
diagram shows the paths of three alpha
particles.
(a) The diagrams present three atoms X , Y
and Z.
Explain the different paths A, B and C of
alpha particles.
…………………………………………………
…………………………………………………
…………………………………………………
…………………………………………………
4
Nuclear Decay
The diagram shows an absorber is placed between a
radioactive source and a G tube.
The absorbers are made from different
materials.
30
The following equation represents the decay of
a Polonium nucleus.
210 Po
 206 Pb + x
84
82
What is particle or ray represented by X ?
A
C
31
Gamma ray
Alpha - particle
Absorber
Without absorber
Thin paper
Aluminium
Lead block
27
28
Reading of counter
/ counts per minute
500
220
50
48
C
D
83
-1
What are X and Y represented?
X
Y
A


B


C


D


33
216
Po nucleus decays and emits an alpha -
84
particle. The new nucleus decays again and
emits a beta - particle. The new nucleus is ____
A
213Pb
B
82
 - decay
Nuclear fusion
C
A radioactive nucleus emits a  - particle. What
is the change in its nucleon numbers?
A
B
C
D
Alpha- particle
Electron
 214 Bi + 0 X + Y
212Bi
83
29
B
D
The following equation represents the decay of
a Plumbum nucleus.
82
In which type of nucleur reaction are the nuclei
heavier after the reaction than they were
before?
 - decay
 - emission
Proton
Gamma - ray
214 Pb
What is the type of radiations emitted by the
source?
A  - particles
B  - particles and  - particles
C  - particles and  - rays
D  - particles , - particles and  - rays
A
C
20
A
C
32
Beta - particle
Proton
The following equation represents the decay of
a Kalium nucleus.
40 K 
40Ca + X
19
The table shows the result obtained from the
counter for different absorbers.
B
D
It decreases by 2
It decreases by 1
It increases by 1
It does not change
5
212 Hg
80
D
213 TI
81
34
What is the number of the alpha particles and
beta particles emitted during this process?
208 nucleus decays and emits two alpha 86
The number of
alpha particles
particles and a beta- particle. The new nucleus
decays again and emits a gamma- ray and a
beta – particle.
K nucleus is represented by ________________
A
200K
B
84
C
202K
D
38
204 K
84
Alpha particle
4
4
4
10
D
Beta particle
6
8
10
4
2
3
4
1
3
2
1
1
The half-life of a radioactive material is
A
B
C
Both alpha and beta particles are produced
218
when 234
90 M decays to 92 N . How many alpha
and beta particles are produced.
A
B
C
D
36
200 K
86
86
35
A
B
C
D
The number of
beta particles
the taken for its activity to be halved
the time for its volume to be halved
the time for its nucleon numbers to be
halved
the time for its proton numbers to be
halved
39
Which of the following graph number of atoms,
against time for a radioactive material is true?
40
In an experiment to find the half-life of
radioactive isotope, the following results were
obtained.
Activity/
410 290 200 140 95 69
count per
minute
Time /
0
2
4
6
8
10
minute
What is the approximate half-life of the isotope?
A nuclide 232 V decays to nuclide 220 W
92
90
and emits alpha- particles and beta- particles.
.How many alpha and beta particles are
produced.
A
B
C
D
37
4  and
3  and
4  and
3  and
3
4
4
3
The diagram shows a series of radioactive
decays for the nucleus of uranium-238 to that of
radium-226.
A
C
E
6
2 minutes
6 minutes
10 minutes
B
D
4 minutes
8 minutes
41
The table shows the activity of a radioactive
source is measured in 160 s .
Time / s
0
40
80
120
160
Activity / number per
second
320
163
82
x
20
What is the value of x?
A
C
E
42
51
39
What is its activity after 12 hours?
A
B
C
D
45
6 days earlier , the mass is 20 g
12 days earlier, the mass is 80 g
6 days later, the mass is 2.5 g
12 days later, the mass is 5.0 g
20
32
120
B
D
46
24
60
47
B
D
25.0%
87.5 %
15
120
480
B
D
30
240
The half-life of carbon is estimated 6 400 years .
A artifact has been discovered. The activity of
carbon in this artifact is ¼ of its initial activity.
How old is the artifact?
A
C
E
7
12.5 %
50. 0%
A recorder records 60 pulses per second for a
radioactive material. The half-life of this source
is 24 seconds. What is the reading of the
recorder in 24 seconds before?
A
C
E
The diagram shows a graph activity against time
for a radioactive element.
4 counts per second
8 counts per second
16 counts per second
64 counts per second
A radioactive source has a half-life 8 hours.
What is the percentage of atoms to decay after
24 hours?
A
C
A recorder records 160 pulses per second for a
radioactive material. The half-life of this source
is 5 days. What is the reading after 15 days?
A
C
E
44
B
D
The initial mass of a radioactive element is 10 g
and its half-life is 6 days.
Which of the following statements about the
mass of the radioactive element is true?
A
B
C
D
43
60
45
31
3 200 years
8 000 years
19 200 years
B
D
6 400 years
12 800 years
48
A radioactive source has a half-life of 12 hours
How long does it take for 75% of the atoms in
the source to decay?
A
C
E
49
B
D
Three different rays P,Q and R are emitted from
a radioactive substance.
The following table shows the characteristics of
the rays.
Type of rays
P
Q
R
Deflection of unchanged unchanged decreases
the gold leaf
of an
electroscope.
Effect on
no spark
no sparks produce
Spark
sparks
Counter
Tracks in
cloud
chamber
12 hours
30 hours
The background reading of a GM tube is 40
counts per minutes . A radioactive source is the
placed near the tube , the reading is 280 counts
per minutes . After 3 hours , its reading drops to
70 counts per minutes . What is the half-life of
the radioactive source??
A
C
E
50
6 hours
24 hours
48 hours
51
1 hour
6 hours
12 hours
B
D
3 hours
9 hour
Penetrating
power
A few
Stopped
Stopped
centimetres by a few
by a sheet
of lead can milimetres of paper
absorb a
of
significant
aluminium
amount of
it
Based on the graph above,
(a) State the nature characteristic of rays
(i) P
…………………………………………
(ii) Q
………………………………………….
(b) Which of the rays has the strongest
penetrating power?
The table shows the half-lives and its initial
masses of two radioactive substances P and .
Radioactive
substance
Half-life / day
Initial mass / g
P
Q
10
1
5
2
How long P and Q take time to become the
same mass?
A
C
E
5 days
15 days
25 days
B
D
10 days
20 days
(c)
…………………………………………………
Explain why
(i) rays P can produce sparks in a spark
counter?
…………………………………………
(ii)
…………………………………………
rays P and Q cannot be detected by
a gold leaf electroscope?
…………………………………………
…………………………………………
(d) Explain why rays R produce thick and
straight tracks in cloud chamber?
…………………………………………
8
52
(a) A radioactive source contains an isotope
of thorium.Thorium ( 22890 Th ) decays by particle emission to radium (Ra).
Write an equation to show this decay.
(c)
All three types of radioactive emission
cause some ionisation of gases.
(i) Explain what is meant by the term
ionisation of gases.
............................................................
............................................................
(b) The radium produced is also radioactive.
Diagram 1 shows a laboratory experiment
to test for the presence of the radioactive
emissions from the thorium source, using a
radiation detector. In the laboratory there is
a background count of 20 counts/minute.
............................................................
............................................................
(ii) Suggest a reason why -radiation
produces very little ionisation.
............................................................
............................................................
............................................................
............................................................
53
The diagram shows part of
238 U
decay series.
The readings are given in the table.
Position
P
Q
Based on the diagram above;
Reading in count / per
minute
2372
361
238 U

State and explain
(i) which radiation could be causing the
count at Q,
...........................................................
.

92
234
Th 
90
230
Th 
90
234
Pa 
91
226
234
U
92
Ra
88
(a) Name the rays or particles emitted when
234 Th decays to 234 Pa
90
...........................................................
91
..................................................................
............................................................
(ii) which radiations could be causing the
count at P.
(b) State a pair of an isotope.
..................................................................
(c) The half life of 234 Pa is 6.7 hours and
............................................................
91
Initially has a mass 32 g.
............................................................
9
10
Radioactive decay
In which type of nuclear reaction are the nuclei
heavier after the reaction than the were before?
A
B
C
D
11
α - decay
β - decay
Nuclear fission
Nuclear fusion
hat happen when two nuclei of deuterium
15
A
C
E
( 21H )
fuse together to form a nucleus helium ( 42 He )
?
A
B
C
D
12
13
Mass and energy are both created
Energy and mass are both lost
Mass is converted into energy
Energy is converted into mass
17
Atom bomb
Hydrogen bomb
Nuclear reactor
B
C
D
Both of the nuclear reactions experience
mass defect
Both of the nuclear reactions produced a
large amount of energy
Both of the nuclear reactions produced
new nuclei
Both of the nuclear reactions require very
high temperature
2.55 x 10 -21J B
3.83 x 10 -13J D
8.97 x 10 -13 J
5.10 x 10 -19 J
7.65 x 10 -13 J
A nuclear reaction is represented by the
following equation:
235
1
93
141
92 U + 0 n → 55 Cs + 37 Rb +
235
92 U = 235.04392 u
Mass of 01n
= 1.00867 u
Mass of 141
55 Cs = 140.91963 u
Mass of 93
37 Rb = 92.92157 u
1 u = 11.7 x 10 -27 kg
Mass of
Speed of light = 3.0 x 10 8 ms-1
(a) What is the value of X?
………………………………………………
(b) Name the nuclear reaction involved.
Which of the following is correct?
C
1.8 x 10 17 J
1.6 x 10 17 J
The information about the equation is shown as
follow:
X→Y+Z
B
B
D
X 01n + energy
A nuclear reaction is given by the equation
A
1.8 x 10 14 J
1.6 x 10 14 J
1.6 x 10 18 J
The mass defect in a nuclear reaction is
0.05 u. What is the released?
[ Speed of light = 3.0 x 10 8 ms-1 ,
1 u = 11.7 x 10 -27 kg ]
A
C
E
Which of the following is not the similarity
between nuclear fission and nuclear fusion?
A
14
16
Which of the following is made by using the
principle of nuclear fusion.
A
B
C
The mass defect in a nuclear reaction is
2 x 10 -3 kg. What is the released?
[ Speed of light = 3.0 x 10 8 ms-1]
The nucleon number of X > The nucleon
number of Y + nucleon number of Z
The proton number of X > The proton
number of Y + proton number of Z
The atomic mass of X > The atomic mass
of Y + the atomic mass of Z
………………………………………………
(c)
What is the meaning of the nuclear
reaction in (b)?
................................................................
10
.................................................................
Equation
Before reaction
H + 3H
2
1
………………………………………………
(d) State one application of the nuclear
reaction in (b)
1
4
2
After reaction
He + 1n +
0
Energy
Total
atomic
mass
………………………………………………
(e) Calculate
5.03013 u
5.01043 u
Table (b)
(i) the energy released .
(a) (i)
(ii)
What is meant by a nuclear fission ?
Using only the information given in
Table(a) and (b), compare nuclear fission
and nuclear fusion. Hence state the
relationship between mass and energy
involved.
(b) Nuclear fission produces a chain reaction.
Describe how the chain reaction happens in a
nuclear fission of an atom of uranium.
(ii)
18
the power generated in 5 µs.
Table (a) shows an equation of a reaction and
total atomic mass before and after a nuclear
fission.
Equation
Nuclear fission
Before reaction
After reaction
239 Pu + 1n
145 Ba + 93Sr +
94
0
56
2 1n
0
Total
atomic
mass
240.06082 u
38
+ Energy
239.85830 u
Table (a)
Table (b) shows an equation of a reaction and
total atomic mass before and after a nuclear
fusion.
Nuclear fusion
11