P5 - Radioactivity Flashcards

1
Q

What did Dalton believe about the atom

A

Everything was made up of solid balls, with different balls for different elements

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2
Q

What did Thomson discover about the atom

A

The existence of electrons

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3
Q

What did Rutherford discover

A

Suggested the idea of a positive nucleus, and believed the negative charge surrounded the nucleus

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4
Q

What did Bohr discover

A

That electrons orbit the nucleus, and are held in shells

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5
Q

How did Rutherford discover the nucleus

A

Fired alpha particles at a sheet of gold

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6
Q

What number is on top of the element symbol (physics)

A

Mass number

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7
Q

Where is the atomic number (in physics)

A

On the bottom

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8
Q

Same number of electrons as

A

Protons

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9
Q

What can happen to unstable isotopes

A

They can decay into other elements

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10
Q

What are alpha particles made up of

A

2 protons and 2 neutrons

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11
Q

What is the overall charge of an alpha particle

A

2+

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12
Q

Why are alpha particles easily absorbed

A

Because they are so large, they are easily stopped by collisions with other molecules

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13
Q

Are alpha particles strongly ionising

A

Yes

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14
Q

What are beta particles made from

A

An electron

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15
Q

What is the charge of a beta particle

A

-1

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16
Q

How are beta particles formed

A

When a nucleus decays into a proton and an electron

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17
Q

Why do beta particles penetrate moderately far into materials

A

because they are so small

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18
Q

How ionising are beta particles

A

Moderately

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19
Q

What would stop a beta particle

A

5mm of aluminium

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20
Q

What does it mean if an object is radioactive

A

It contains unstable isotopes

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21
Q

What are the 4 types of radiation emmited by an isotope

A

Alpha, Beta, Gamma, and the emission of a neutron

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22
Q

What is gamma radiation

A

Electromagnetic waves

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23
Q

Why is gamma radiation weakly ionising

A

Because it has no mass or charge

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24
Q

How far can gamma rays travel

A

thick sheets of lead needed to stop them

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25
Q

What is the emission of a neutron

A

If a nucleus has too many neutrons, it can emit a neutron to stabilize

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26
Q

How do you write an alpha particle (for a nuclear equation)

A

4
He
2

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27
Q

What does a isotope lose if it emits an alpha particle

A

4 from the mass number
2 from the atomic number

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28
Q

What is a nuclear equation for alpha decay

A

Old element (+ mass and atomic no.) —–> He (4 , 2) + New element (-4 from mass - 2 from atomic)

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29
Q

What is beta decay

A

Involves a neutron turning into a proton and emitting a fast moving electron

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30
Q

What is the nuclear equation for beta decay

A

Element —> New element (plus 1 atomic number) + electron

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31
Q

What gets added to the atom when beta decay occurs

A

Atomic number adds 1, as a proton has been made

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32
Q

How do u write an electron for beta decay formula

A

0
e
-1

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33
Q

What gets added in gamma radiation formula

A

Fancy Y, nothing else

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34
Q

What gets added in the equation for neutron emission

A

1 gets removed from the mass number, and the atomic number stays the same

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35
Q

What is neutron emission equation

A

Element —> same element-1mass + neutron

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36
Q

Can the decay of any given isotope be predicted?

A

No, it is completely random

37
Q

What is the activity of a sample

A

The overall rate of decay

38
Q

What is a Becquerel a measurement of

A

Radioactive decay

39
Q

What is the symbol for Becquerels

A

Bq

40
Q

What is 1 Bq

A

1 decaying isotope per second

41
Q

What is half life

A

Time taken for number of radioactive isotopes in a sample to halve
Time taken for activity of a sample to halve

42
Q

Why does activity decrease the more nuclei decay?

A

Because there are less remaining nuclei to decay, so the process slows

43
Q

How do u calculate the half life on a activity, time graph

A

Work out how long it took for the activity to halve

44
Q

How do you find the activity of a sample

A

Use a geiger counter

45
Q

How do geiger counters calculate the activity of a sample

A

They record all the decays that reach them per second

46
Q

What is the count rate

A

The amount of decays a geiger counter receives per second

47
Q

What does irradiation mean

A

The process by which objects are exposed to any type of radiation (ionising or non)

48
Q

What is contamination

A

When radioactive particles get on the surface of other objects.

49
Q

Why can contamination be dangerous

A

Because if the particles decay, you can be subjected to harmful radiation

50
Q

What 3 factors determine the danger of radiation

A

Type of radiation
Location on body of exposure
Amount of radiation you receive

51
Q

Why is ionising radiation dangerous

A

Because it can ionise your DNA and cause mutation or cancer

52
Q

What is the only non-ionising radiation that can cause cancer

A

Ultraviolent radiation

53
Q

If the source is outside the body, what is the order of danger in radioactive particles

A

Beta, (most)
Gamma,
Alpha (least)

54
Q

If the source is on or in the body, what is the order of danger in radioactive particles

A

Alpha, (most)
Beta,
Gamma (least)

55
Q

What is the amount of radiation received called

A

Dosage

56
Q

What 3 factors can reduce the dosage of radiation

A

Distance from source
Length of exposure
Radioactivity of sourcef

57
Q

How can you protect against dangers caused by radiation

A

Wear protective gear
Handle substances with tongs
Keep substance in lead lined box

58
Q

What can happen to cells if they receive a large enough dosage of radiation

A

Cells can be killed

59
Q

What causes radiation sickness

A

Large scale death of cells, caused by radiation exposure

60
Q

What are some symptoms of radiation sickness

A

Hair loss,
Vomiting,
Tiredness

61
Q

What two ways can radiation be used to kill cancer cells

A

Externally or Internally

62
Q

What is external cancer treatment

A

Gamma rays target cancer site, from many different angles

63
Q

What is internal cancer treatment

A

Radioactive source is placed inside the body, either in or next to the cancer source.

64
Q

What type of radiation is used for internal cancer treatement

A

Beta particles

65
Q

What is a medial tracer

A

Placing a radioactive isotope in a person’s body by ingestion or injection, we can track its movement and check if particular organs are working properly.

66
Q

What type of radiation is used in medical tracers

A

Gamma, as it is the least harmful

67
Q

What kind of half life do the isotopes used in medical tracers have

A

The shortest possible, only emitting radiation while they are being measured

68
Q

What is nuclear fission

A

The splitting of a large, unstable nuclei

69
Q

What are the 2 types of fission

A

Spontaneous fission, and fission by absorbing a neutron

70
Q

What is spontaneous fission

A

Fission which happens by itself, unforced

71
Q

Which type of fission is rare

A

Spontaneous fission

72
Q

What is the other type of fission

A

Absorbing a neutron into an atom makes it even more unstable, which gets the process of fission started

73
Q

What is the process of fission (chain reaction)

A

Fire a slow moving nuclei at a large unstable isotope, which makes it more unstable, and causes it to split into 2 daughter nuclei, as well as releasing a few more neutrons and LOTS of energy in the form of gamma radiation. These neutrons then hit more isotopes and repeat the process of fission.

74
Q

What type of energy is given off during fission

A

Gamma radiation

75
Q

Symbol for neutron

A

n

76
Q

What does nuclear fission lead to

A

A chain reaction

77
Q

What can happen if fission is not controlled

A

It can quickly get out of hand and release massive amounts of energy

78
Q

How can you control the rate of fission in a nuclear power plant

A

By lowering control rods into the reactors, which absorb neutrons and therefore slow the fission down

79
Q

What are the pros of nuclear power

A

Cheap fuel,
Clean and steady energy

80
Q

What are the cons of nuclear power

A

Power stations are pricey to build
Nuclear waste is expensive to dispose of

81
Q

What is fusion

A

2 light nuclei fuse to make one single larger nuclei.

81
Q

What process fuels stars

A

Nuclear fusion

82
Q

Why does fusion produce so much energy

A

Because during the process, some mass is lost from the nuclei (source: trust me bro) and E = MC^2 means lots of energy is released

83
Q

How are all elements heavier than hydrogen made

A

Fusion

84
Q

What is good about fusion

A

it makes NO nuclear waste, and hydrogen (the fuel) is very easy to access

85
Q

What is the issue with fusion

A

It needs 10,000,000 degrees celsius of heat, and lots of pressure, so it is not yet possible on earth

86
Q

What releases more energy per mass of fuel fission or fusion

A

fusion produces much more

87
Q

What is the size of an atom

A

1x10^-10 m