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GCSE Physics Yr 10 > P7- Radioactivity > Flashcards

P7- Radioactivity Flashcards

1
Q

What is a mass number?

A

The number of protons and neutrons in a nucleus.

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2
Q

What is an atomic number?

A

The number of protons( which equals the number of electrons) in an atom. It is sometimes called the proton number.

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3
Q

What is an ion?

A

A charged atom or molecule.

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4
Q

What is an isotope?

A

Atoms with the same number of protons and different numbers of neutrons.

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5
Q

What is a nucleon?

A

A particle found in the nucleus.

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6
Q

What is nuclear radiation?

A

Radiation that comes from the nucleus.

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7
Q

What is an atom?

A

The smallest part of an element that can exist.

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8
Q

Define the term neutral?

A

Something that carries no charge.

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9
Q

Define positive.

A

(+) ions, something that carries a positive charge.

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10
Q

Define negative

A

(-) ions, something that carries a negative charge.

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11
Q

What is a proton?

A

A particle that is positively charged, it has an equal and opposite charge to that of an electron.

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12
Q

What is a neutron?

A

An uncharged particle. Has the same mass as protons, and lives in the nucleus with the proton.

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13
Q

What is an electron?

A

A tiny negatively charged particle that moves around the nucleus of an atom.

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14
Q

A mass number is…

A

Protons and neutrons

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15
Q

The atomic number is….

A

Protons

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16
Q

What determines the element of an atom?

A

The number of protons.

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17
Q

What does the chemical behavior of an element determine?

A

The number of electrons.

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18
Q

Define ionizing radiation?

A

When the nucleus of an atom decays, it gives out energy and potentially alpha or beta particles. When these come in contact with a neutral atom they remove an electron, causing the atom to have an overall charge, becoming an ion. This is called ionising radiation.

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19
Q

What happens when an electron absorbs a photon of light?

A

It moves up an orbital.

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20
Q

What happens when an electron moves down a level?

A

It will release a photon of light.

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21
Q

How much smaller is an electron?

A

2000x smaller

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22
Q

What is Daltons model?

A

Dalton said that substances were made up of identical, solid spheres. It was thought that all matter was made up of indivisible particles called atoms.

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23
Q

What is the plum pudding model?

A

JJ Thomson discovered that there were smaller particles, now called sub- atomic particles. It was though that the atom was a ball of positive charge, with electrons dotted throughout it, like plums in plum pudding.

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23
Q

What came after the plum pudding model?

A

The nuclear model. Rutherford then conducted an experiment which proved that the atom is mostly empty space, with a positively charged mass concentrated in a tiny volume at the centre of the atom.

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24
Q

What did the gold foil experiment show to rutherford?

A

That the faster the alpha particles were traveling , the less they were deflected.

The stronger the positive charge on the nucleus, the more Alpha particles where deflected.

It was concluded that most alpha particles went straight through the substance, meaning that the atom is mostly empty space.

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25
Q

What was the gold foil experiment?

A

Beams of alpha particles were fired at a 400 atom thick piece of gold foil, and were predicted to pass straight through the gold or only be slightly deflected.

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26
Q

What actually happened during the gold foil experiment?

A

Some alpha particles were deflected but a few were completely rebounded.

27
Q

What was the zinc sulphide screen around the foil for?

A

It gave out scintillations (tiny sparks of light) when they were hit by an alpha particle.

28
Q

1 Bq is ….

A

1 count per second.

29
Q

Which radiation particle has the strongest ionising power?

A

Alpha particles.

30
Q

Lowest ionising power?

A

Gamma rays

31
Q

Weakest penetrating power and what is it stopped by?

A

Alpha, it is stopped by skin/ paper.

32
Q

Strongest penetrating power and what is it stopped by?

A

Gamma rays because they are waves, stopped by thick lead.

33
Q

What stops Beta particles?

A

Thin aluminum .

34
Q

Which particle has a helium nucleus?

A

Alpha particles.

35
Q

Which particle is a fast moving electron?

A

Beta particle.

36
Q

Define irradiation.

A

When an object is exposed to ionising radiation but does not become radioactive.

37
Q

Define radioactive contamination.

A

The unwanted presence of materials containing radioactive atoms or other materials.

38
Q

What are some safety precautions when working with radiation?

A

Keep as far away as possible.
Spend as little time possible in risk areas.
Shield yourselves by staying behind thick concrete barriers or using led plates.

39
Q

What is the general equation for alpha decay?

A

A A-4 4
X Y + Alph
Z Z-2 2

40
Q

General equation for beta decay?

A

A A 0
X Y Beta
2 2+1 -1

41
Q

General equation for gamma decay?

A

Gamma is not a particle, and so does not effect the structure of the nucleus. It is often seen alongside Alpha or Beta decay.

42
Q

Define background radiation

A

Radiation released naturally ,y by things around us.

43
Q

Uncertainty in mean….

A

Range/2

44
Q

What is the activity of a radioactive source?

A

Number of unstable atoms in the source that decay per second.

45
Q

How can we monitor activity?

A

By using the count rate of the sample. It will tell us how many counts per second are detected.

46
Q

Define half life.

A

The time taken for half the radioactive nuclei in a sample to decay. ( for the count rate to fall to half its initial value).

47
Q

What are radioactive tracers?

A

They trace the flow of a substance through an organ. The tracer contains a radioactive isotope that emits gamma radiation, as it can be detected outside the system.

48
Q

What is an example of a radioactive tracer?

A

Iodine to find out if a patients kidney is blocked.

49
Q

What would the reading pick up a normal kidney to be?

A

The radioactive substance will flow in and out, so the reading will go up then down.

50
Q

What would the reading of a blocked kidney be?

A

The radioactive substance has flown in but not back out again. The reading goes up and stays up.

51
Q

Why is radioactive iodine used for kidney tests?

A

It has a good half life of 8 days, meaning that it has enough time to get to the kidneys but not long enough to damage the body.
Gamma is able to pass through anything so the iodine will not be stopped by an organ.
The daughter nuclei are stable- It decays so it will have a weaker activity.

52
Q

What is a gamma camera?

A

Used to take pictures of internal organs.
Patient is injected with radioactive substance which is absorbed by the organ.
A gamma camera is placed against a patients skin and detects the radiation emitted by the solution.

53
Q

Why do we rotate a gamma beam?

A

It has a high dose of radiation and could kill all the living cells. The beam is rotated give the healthy surrounding tissues a break but the tumor is targeted each time.

54
Q

What is Brachytherapy?

A

Where a radioactive source is implanted next to the tumor.

55
Q

What is nuclear fission?

A

A type of nuclear reaction that is used to release energy from large unstable atoms (usually uranium or plutonium) by splitting them into smaller atoms.This rarely happens spontaneously, usually the nucleus will absorb a neutron before it will split.

56
Q

What is a fissile material?

A

A material (uranium 235) that can go through the splitting process easier.

57
Q

What is the process if nuclear fission?

A

1.A slow neutron is absorbed by a uranium 235 nucleus.
2. The resulting nucleus of uranium 236 is unstable.
3. It splits apart forming 2 lighter nuclei, 3 neutrons and gamma radiation.
4. The reaction continues. This is called a chain reaction.

58
Q

How does nuclear energy travel to the grid?

A

The process is controlled so the heat energy is released over a longer period of time, and is used to heat water. The steam produced will drive a turbine to turn a generator.

59
Q

What is a graphite moderator?

A

Slows down the released neutrons so they can be absorbed.

60
Q

What are control rods?

A

Made from boron, they can lower retract. It absorbs neutrons and slows reactions.

Raising rods= speeding up reaction

Lowering rods= slowing down reaction.

61
Q

What are fuel rods?

A

Hollow rods that contain the pellets if uranium fuel.
Uranium is non renewable, but nuclear fuel has a high energy density!

62
Q

What does concrete shielding do?

A

Prevents radiation from escaping the reactor core

63
Q

What is nuclear Fusion?

A

It involves joining together of the nuclei which produces a large amount if energy.

64
Q

What are the differences between nuclear fission and fusion?

A

Fusion releases even more energy per kg of fuel.
Fusion makes less radioactive emissions as many of the products are stable.
Fusion uses cleaner fuel. Isotopes of hydrogen, which can be made from water, and lithium. The end product is helium, which is a harmless and non- radioactive gas.

65
Q

Why does the fuel have to be heated to around 150 million degrees?

A

So the nuclei can travel fast enough to get enough energy to overcome the electrostatic repulsion ( repulsion from like charges)

66
Q
A

GCSE Physics Yr 10 (8 decks)

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