1
1
What is correct for an electron?
electron charge
position of electron in atom
A
negative
outside the nucleus
B
negative
part of the nucleus
C
positive
outside the nucleus
D
positive
part of the nucleus
[1]
[Total: 1]
2
The nucleus of an isotope of plutonium has 94 protons and 147 neutrons. The chemical symbol
for plutonium is Pu.
Write the nuclide notation that describes this nucleus.
[2]
[Total: 2]
3
Only one isotope of gold occurs naturally on Earth.
State what this indicates about the nuclear structure of all the naturally occurring atoms of gold on
Earth.
..................................................................................................................................................
..................................................................................................................................................
[1]
[Total: 1]
2
4
Only one isotope of gold occurs naturally on Earth.
There are several artificially produced isotopes of gold.
Gold-198 (198
79 Au) is an artificial isotope which is used in medicine and in scientific research.
Gold-198 decays by β (beta)-emission to a stable isotope of mercury.
Determine the number of protons and the number of neutrons in a nucleus of this isotope of
mercury.
number of protons = ...............................................
number of neutrons = ............................................. [2]
[Total: 2]
5
In nuclide notation,
For one neutral atom of
represents one nuclide of chlorine.
, state:
1. the nucleon number .............................................................................................................
2. the proton number ................................................................................................................
3. the number of neutrons. .......................................................................................................
[3]
[Total: 3]
6
Complete this sentence about a neutral atom.
In a neutral atom, the number of protons is equal to the number of ................................. .
[1]
[Total: 1]
3
7
An isotope of beryllium, Be, has the nuclide notation:
9
4Be
The diagram shows one atom of this isotope.
electron
X
Y
(not to scale)
Complete the labelling of the diagram. State the names for X and for Y.
X .............................................................................
Y .............................................................................
[2]
[Total: 2]
8
In a nuclear fusion reactor, a nucleus of hydrogen-2 fuses with a nucleus of hydrogen-3 at an
extremely high temperature. This fusion reaction produces an isotope of element X and releases
a neutron.
Using nuclide notation, complete the equation for this reaction.
+
→
[2]
[Total: 2]
4
9
(a) Write down the nuclide equation for this decay of protactinium-234.
[3]
[Total: 3]
10 Two of the isotopes of hydrogen are hydrogen-2 (
) and hydrogen-3 (
).
State one similarity in the composition of their nuclei.
..................................................................................................................................................
[1]
[Total: 1]
11
Two of the isotopes of hydrogen are hydrogen-2 (
) and hydrogen-3 (
).
Describe how a nucleus of hydrogen-3 differs from a nucleus of hydrogen-2.
..................................................................................................................................................
..................................................................................................................................................
[2]
[Total: 2]
5
12 The diagram shows a beam of α-particles moving towards a thin sheet of gold in a vacuum.
Detectors in the region surrounding the thin gold sheet detect the α-particles and determine the
number of particles that travel in various directions.
State and explain what can be deduced from the following observation.
A very small number of α-particles are deflected through very large angles or return back the way
they came.
deduction .................................................................................................................................
explanation ...............................................................................................................................
..................................................................................................................................................
[2]
[Total: 2]
13 State two differences between nuclear fission and nuclear fusion.
1 ...............................................................................................................................................
..................................................................................................................................................
2 ...............................................................................................................................................
..................................................................................................................................................
[2]
[Total: 2]
6
14 The diagram represents a neutral atom of an isotope of element X.
The isotope of element X is radioactive. It decays to form an isotope of element Y by emitting a
β-particle.
Using the diagram, deduce the nuclide notation for the isotope of Y produced by this decay.
[3]
[Total: 3]
7
15 The diagram shows a beam of α-particles moving towards a thin sheet of gold in a vacuum.
Detectors in the region surrounding the thin gold sheet detect the α-particles and determine the
number of particles that travel in various directions.
State and explain what can be deduced from the following observation.
A small number of α-particles are deflected as they pass through the gold sheet.
deduction .................................................................................................................................
explanation ...............................................................................................................................
..................................................................................................................................................
[2]
[Total: 2]
8
16 The diagram shows a beam of α-particles moving towards a thin sheet of gold in a vacuum.
Detectors in the region surrounding the thin gold sheet detect the α-particles and determine the
number of particles that travel in various directions.
State and explain what can be deduced from the following observation.
The majority of the α-particles pass through the gold sheet undeflected and are detected on the
far side.
deduction .................................................................................................................................
explanation................................................................................................................................
..................................................................................................................................................
[2]
[Total: 2]
17 S is a radioactive source emitting ,
10 cm from S.
and -radiations. Y is a sheet of aluminium 2 cm thick placed
Y
2 cm
S
G
10 cm
Which radiations can be detected at G?
A
only
B
and
C
only
D
and
[1]
[Total: 1]
9
18 When an 8.0 g sample of radon decays, it turns into other nuclides, as shown.
4g
other
nuclides
8g
radon
6g
other
nuclides
4g
radon
time = 0
after
one minute
7g
other
nuclides
2g
radon
1 g radon
after
two minutes
after
three minutes
?
after
four minutes
How much radon will there be after four minutes?
A
0
B
0.5 g
C
7.5 g
D
8.0 g
[1]
[Total: 1]
19 The carbon in the body of all animals contains some radioactive carbon. At the time when any
animal dies, each gram of carbon in its body emits about 16 -particles per minute.
Some animal remains are discovered. It is found that 4 -particles are emitted per minute for
each gram of carbon in the remains.
The half-life of radioactive carbon is 6000 years.
How old are the remains of the animal?
A
1500 years
B
3000 years
C
6000 years
D
12 000 years
[1]
[Total: 1]
10
20 Paper coming out of a photocopier sometimes carries a negative charge which makes it stick to
things.
A radioactive source is used to reduce this charge, as shown in the diagram.
paper in
photocopier
negatively charged
paper out
radioactive source
Which type of source is most effective in reducing the negative charge?
A
-particle
B
-particle
C
-ray
D
neutron
[1]
[Total: 1]
21 α (alpha)-particles, β (beta)-particles and γ (gamma)-rays have different characteristics.
Complete the table by indicating with a tick (✓) the correct type of radiation for each characteristic.
The first row is done for you.
type of radiation
characteristic
α (alpha)-particles
electromagnetic wave
β (beta)-particles
γ (gamma)-rays
✓
least ionising
least penetrating
a helium nucleus
negatively charged
[3]
[Total: 3]
11
22 Only one isotope of gold occurs naturally on Earth. There are several artificially produced isotopes
of gold.
Gold-198 is an artificial isotope which is used in medicine and in scientific research.
A sample of gold-198 is placed near to a radiation detector in a research laboratory. The count rate
is recorded at the same time every day for 32 days.
The results are used to plot the graph.
400
count rate
counts / min
300
200
100
0
0
4
8
12
16
20
24
28
time / days
(a) Using the graph, determine the background count rate in the research laboratory.
count rate = ...................................................... [1]
(b) Using the graph, determine the half-life of gold-198.
half-life = ...................................................... [4]
[Total: 5]
23 A teacher determines the types of emission from a radioactive source. He uses different materials
to absorb the emissions. The diagram shows the equipment.
32
12
2 cm
radioactive source
000000
detector
counter
material
being tested
(not to scale)
The teacher places a material between the radioactive source and the detector. The counter shows
the count rate for the emission that reaches the detector. The teacher records the count rate. He
repeats the experiment for different materials.
The table shows the results.
material being tested
air (no object in gap)
480
thin sheet of paper
481
2 mm sheet of aluminium
479
10 mm block of lead
120
(a) State whether the source emits α (alpha)-particles.
Use information from the table to give a reason for your answer.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
[2]
13
(b) State whether the source emits γ (gamma)-rays.
Use information from the table to give a reason for your answer.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
[2]
[Total: 4]
24 An isotope of americium has 95 protons and 146 neutrons in its nucleus.
The graph shows how the count rate of a sample of americium changes with time.
18 000
count rate
counts / min
16 000
14 000
12 000
10 000
8000
6000
4000
2000
0
0
100 200 300 400 500 600 700 800 900 1000 1100 1200 1300
time / years
Determine the half-life of the americium in the sample. Use information from the graph.
half-life = .............................................. years
[2]
[Total: 2]
14
25 The diagram shows the paths of three α-particles moving towards a thin gold foil. Four gold nuclei
are shown.
gold nuclei
paths of
a-particles
(not to scale)
On the diagram, complete the paths of the three α-particles.
[3]
[Total: 3]
26 The diagram shows a β-particle moving in the direction of the arrow between two poles.
S
b-particle
N
direction of travel of b-particle
when in the position shown
On the diagram, draw an arrow to show the direction of the force on the β-particle due to the
magnetic field.
[2]
[Total: 2]
15
27 A student places a sample of an isotope of protactinium (Pa-234) near a radiation detector.
The readings on the detector, taken every 20 s, are recorded in the table.
count rate
counts / min
time / s
0
101
20
88
40
76
60
66
80
58
100
51
120
46
140
42
160
38
180
35
The graph shows the count rate due to this sample against time.
count rate
counts / min
80
70
60
50
40
30
20
10
0
0
20
40
60
80
100 120 140 160 180
time / s
Explain why the readings in the table are not the same as those plotted on the graph.
..................................................................................................................................................
..................................................................................................................................................
[2]
16
[Total: 2]
28 The diagram shows a simple diagram of a smoke detector. The smoke detector contains a small
sample of americium-241. This isotope emits alpha particles and ionises the air between the metal
plates in the detector.
detector circuit
radioactive
source
metal plates
air flow
Suggest and explain two reasons why smoke detectors use an isotope that emits α-particles rather
than an isotope that emits γ-radiation.
1. ..............................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
2. ..............................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
[2]
[Total: 2]
29 The isotope americium-241 is represented by
This isotope decays by an α-emission to an isotope of neptunium (Np).
Complete the nuclide equation for this decay.
[3]
[Total: 3]
17
30 The diagram below is a simple diagram of a smoke detector. The smoke detector contains a small
sample of americium-241.
Americium-241 decays by an α-emission to an isotope of neptunium (Np).
This isotope ionises the air between the metal plates in the detector.
detector circuit
radioactive
source
metal plates
air flow
Describe how the americium-241 ionises air.
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
[3]
[Total: 3]
31 Radioactive nuclides can be used in medicine as radioactive tracers.
State another use of radioactive nuclides in medicine.
..................................................................................................................................................
..................................................................................................................................................
[1]
[Total: 1]
18
32 The diagram shows a beam of α-particles, β-particles and γ-rays directed between two metal plates
P and Q.
The metal plates are parallel and there is a large potential difference (p.d.) between them.
Plate P is positive and plate Q is negative.
On the diagram, draw the paths of each of the radiations between the plates and after leaving the
plates.
Label the paths α, β and γ.
[5]
[Total: 5]
33 A beam consists of α-particles, β-particles and γ-rays.
Explain how a uniform magnetic field may be used to separate the α-particles, the β-particles and
the γ-rays
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
[3]
[Total: 3]
19
34 An isotope of an element is radioactive. It decays by emitting a β-particle.
β-particles ionise the air they pass through less strongly than the same number of α-particles.
Suggest why this is so.
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
[3]
[Total: 3]
35 A radioactive isotope is placed near a detector. The readings on the detector are corrected for
background radiation and recorded every hour.
The table shows the corrected readings.
time / hours
count rate / counts per second
0
1.0
2.0
3.0
4.0
500
375
280
210
160
What is the half-life of the isotope?
A
between 0 and 1 hour
B
between 1 hour and 2 hours
C
between 2 hours and 3 hours
D
between 3 hours and 4 hours
[1]
[Total: 1]