1 What is the difference between an atom and a molecule?
A molecule is two or more atoms bonded together.
2 What is an element?
substance where all atoms have the same atomic number/number of protons
3 What is the part in the middle of an atom called?
4 Name two subatomic particles.
any two from: proton, electron, neutron
5 What are the negatively charged particles in an atom called?
6 What are the positively charged particles in an atom called?
7 Where is most of the mass of an atom concentrated?
8 Which subatomic particles have a negligible mass?
9 How did scientists discover that atoms had tiny nuclei?
fired particles at atoms/gold sheet
10 Who investigated atoms in this way?
11 Which of the following is approximately the diameter of an atom ? a hundredth of a millimetre, a thousandth of a millimetre or a millionth of a millimetre?
millionth of a millimetre
12 What charge do electrons have?
negative, or -1
13 How much mass do electrons have?
negligible / hardly any
14 In Thompson?s model, the atom was positively charged with tiny negative charges in it. What was this model called?
plum pudding model
15 Rutherford investigated the structure of the atom. What did he do?
He fired alpha particles at gold foil.
16 What happened to most of the alpha particles in Rutherford?s experiment?
went straight through
17 Why did Rutherford conclude that most of the mass of the atom was in the centre?
A few particles bounced back.
18 What is the relative mass of a proton?
19 What are isotopes?
atoms of the same element with different masses
20 Which subatomic particle has no charge?
21 What is another name for nucleon number?
22 What is the mass number of an atom?
total number of protons and neutrons
23 What is the atomic number of an atom?
number of protons
24 What is another name for atomic number?
25 What is the relative mass of a neutron?
26 What is the relative charge on a proton?
27 What is different between two isotopes of the same element?
number of neutrons in the atomic nucleus
28 How are electrons arranged in an atom?
29 What is ionisation?
when an atom gains or loses an electron
30 Where are the positive charges in an atom?
31 What happens to one or more electrons when an atom gains energy?
jump to higher orbits/shells/energy levels
32 Name two ways in which an atom can gain energy.
any two from: by heating, by electricity, by electromagnetic radiation
33 What happens to electrons when the atom loses energy?
They fall to a lower orbit/shell/energy level.
34 What is ionisation?
when an atom absorbs enough energy to let an electron escape completely
35 What charge does an ion have when it has lost an electron?
36 Name one source of background radiation in everyday life.
any sensible source, such as space, food, rocks etc.
37 Name one thing that can detect radiation.
Geiger Muller tube/photographic film
38 What is ionising radiation?
radiation that can cause atoms to form ions
39 Is most background radiation natural or from human causes?
40 Where does radon gas come from?
uranium in some rocks
41 What are cosmic rays?
charged particles from stars
42 Why is background radiation different in different places?
different rocks and/or building materials
43 What happens to photographic film when radiation hits it?
45 What is a count rate?
the number of clicks/the number of radiation events detected per second
46 Which high-frequency electromagnetic waves can be produced by radioactive decay?
47 What is an alpha particle?
helium nucleus, or two protons and two neutrons
48 What is a beta particle?
electron ejected from the nucleus of an atom/high-speed electron
49 What is the relative mass of an alpha particle?
50 What is the relative charge on an alpha particle?
51 What is the relative charge on a beta particle?
52 What is the relative charge on a positron?
53 Which form of radiation is the most penetrating?
54 Which form of radiation is the most ionising?
55 What happens to the nucleus of an atom when it emits an alpha particle?
becomes more stable/changes to a different element
56 What happens to the nucleus of an atom if it ejects a neutron?
changes to a different isotope of the same element
57 What happens to the atomic number of a nucleus when an alpha particle is emitted?
It goes down by 2.
58 What happens to the mass number of a nucleus when an alpha particle is emitted?
It goes down by 4.
59 How is a beta particle formed?
a neutron changes into a proton and an electron
60 What happens to the atomic number of a nucleus when a beta particle is emitted?
It goes up by 1.
61 How is a positron formed?
A proton changes into a neutron and a positron.
62 What happens to the atomic number of a nucleus when a positron is emitted?
It goes down by 1.
63 What does the activity of a radioactive source refer to?
the number of decays per second
64 What does half-life mean?
the time it takes for the activity to halve, or for the number of unstable nuclei to halve
65 What is the unit for measuring the activity of a source?
66 What does 1 becquerel represent?
1 decay per second
67 Why can we not predict exactly how many nuclei will decay each second?
Decay is a random process.
68 How does the activity of a radioactive source change over time?
It gets less.
69 What does the half-life tell you about the activity of a sample of radioactive material?
the time until the activity falls by half
70 Name one disease that can be caused by radiation.
71 Name one type of job that may involve being exposed to nuclear radiation.
hospital worker/nurse/doctor or scientist or nuclear power station worker
72 What has happened if you are contaminated by radioactive material?
you have got it on your skin or inside your body