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Z: Physics - Yr 10 > Components of Atoms and Radioactivity > Flashcards

Components of Atoms and Radioactivity Flashcards

Aligned with Kognity (123 cards)

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1
Q

Complete the following sentences.

A prefix of k before a unit means the measurement is one thousand times __ than the SI unit.

A prefix of m before a unit means the measurement is one thousand times __ than the SI unit.

A

A prefix of k before a unit means the measurement is one thousand times more than the SI unit.
​
A prefix of m before a unit means the measurement is one thousand times less than the SI unit.

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2
Q

Can atoms be seen with an optical microscope?

A

No

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3
Q

What are the three main constituent parts of an atom?

A

Protons, neutrons, and electrons.

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4
Q

True or False: Protons have a negative charge.

A

False.

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5
Q

What is the charge of an electron?

A

-1 elementary charge.

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6
Q

Fill in the blank: Neutrons have no charge and are found in the ______ of an atom.

A

nucleus.

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7
Q

What is the approximate mass of a proton in atomic mass units (amu)?

A

1 amu.

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8
Q

Which particle has a much smaller mass, protons or electrons?

A

Electrons.

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9
Q

Multiple choice: Which particle carries a positive charge? A) Neutron B) Electron C) Proton

A

C) Proton.

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10
Q

What is the mass of a neutron in atomic mass units (amu)?

A

Approximately 1 amu.

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11
Q

True or False: The mass of an electron is negligible compared to protons and neutrons.

A

True.

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12
Q

What is the overall charge of a neutral atom?

A

Zero.

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13
Q

What are the symbols of protons, neutrons and electrons?

A

p, n, e

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14
Q

What is the relevent mass of an electron?

A

0(1/2000)

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15
Q

What is a nuclide?

A

An atom or nucleus characterised by a specific number of protons and neutrons.

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16
Q

What is special notation (also called nuclide notation)?

A

A notation using symbols for elements along with atomic number and nucleon number to describe the composition of an element’s nucleus.

Z is the proton number but is also called the atomic number. This is the number of protons found in the nucleus. Since atoms are neutral, this is also the number of electrons orbiting the nucleus.
A is the nucleon number (also known as mass number). This is the total number of protons and neutrons that are found in the nucleus.

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17
Q

Shortly after the big bang, what was the only element present?

A

Shortly after the Big Bang, billions of years ago, the only element in existence was hydrogen.

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18
Q

After the big bang, how were the various elements formed?

A

Through nuclear fusion.

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19
Q

What is nuclear fusion?

A

Nuclear fusion is the process by which lighter nuclei collide with high energy and join to form a larger nucleus (Figure 4). When this happens, energy is released. Fusion happens in stars, such as the Sun.

(Regarding the image) Two hydrogen nuclei join to form a helium nuclei and energy is released. Look closely at the equation showing the nuclide notation. The total nucleon number (mass number) is the same before and after the fusion. Therefore, the total mass is conserved.

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20
Q

What is nuclear fission?

A

Nuclei with very large nucleon numbers have heavy nuclei and are often unstable. Due to this instability, heavy nuclei break apart. This can happen either completely independently or if a neutron is fired into the large nucleus, triggering it to break apart. This process is called nuclear fission (Figure 5). Energy is released in nuclear fission. Fission is the process used in nuclear power stations to generate electricity

In Figure 5, a neutron is fired into the uranium-235 nucleus, causing the nucleon number to increase. A larger mass makes the nucleus unstable. Nuclear fission then occurs and the heavy nucleus splits into krypton and barium with three spare neutrons. Notice that the total mass number is conserved.

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21
Q

In an alpha-particle scattering experiment, which of the following observations proves that the nucleus is small, positively charged and contains most of the mass of an atom?
1. Most alpha particles travel through the gold foil.
2. Alpha particles have a relative charge of +2.
3. Some alpha particles are deflected backwards, towards the source.
4. Some alpha particles are deflected slightly.

A

Some alpha particles are deflected backwards, towards the source.

The nucleus causes some alpha particles to rebound backwards, meaning the positive alpha particles are repelled when they collide. This very rarely happens, indicating the size of the nucleus is small.

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22
Q

Give the name of the particles that Rutherford fired at this gold foil to prove the structure of the atom.

A

Alpha particles

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23
Q

During Rutherford’s test most of the alpha particles travelled straight through without being deflected. What does this indicate?

A

Most of the atom is empty space.

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24
Q

Fill in the gap.
__ is the process in which light nuclei join together.
__ is the process in which heavy nuclei break apart.

A

Fusion is the process in which light nuclei join together.
Fission is the process in which heavy nuclei break apart.

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25
What are the sources of background radiation?
Natural sources, cosmic rays, and human-made sources ## Footnote Background radiation comes from various sources, including radon gas from the ground, cosmic rays from space, and medical procedures.
26
How is background radiation measured?
Using Geiger counters, dosimeters, and ionization chambers ## Footnote These instruments detect and quantify the amount of radiation exposure.
27
What are the three types of radioactive decay?
Alpha decay, beta decay, and gamma decay ## Footnote Each type of decay involves different particles and energy emissions.
28
How do you determine the half-life of a radioactive isotope?
By measuring the time taken for half of the radioactive atoms to decay ## Footnote This is often done through experiments or calculations based on decay rates.
29
List safety precautions when working with radioactive materials.
* Use shielding * Maintain distance * Limit exposure time * Use protective equipment ## Footnote These precautions help minimize radiation exposure and protect health.
30
What are the applications of various radioactive isotopes?
* Medical imaging * Cancer treatment * Radiocarbon dating * Industrial gauging ## Footnote Radioactive isotopes have diverse applications in medicine, archaeology, and industry.
31
What is a nuclear decay equation?
An equation that represents the transformation of a radioactive isotope into a different element or isotope ## Footnote It shows the initial isotope, emitted particles, and resulting isotopes.
32
Identify the part of the electromagnetic spectrum that has the highest energy.
Gamma rays ## Footnote Gamma rays are a form of high-energy radiation emitted during radioactive decay.
33
What is ionising radiation?
Ionising radiation is emitted when unstable nuclei break apart, carrying enough energy to strip away electrons from atoms and create ions. This process can be harmful to living things and damage electronics.
34
What are the types of ionising radiation?
There are three types of ionising radiation: alpha particles, beta particles, and gamma radiation.
35
What is background radiation?
Background radiation is the radiation that is present in our environment at all times, but not at harmful levels. It can be natural or artificial.
36
What are some natural sources of background radiation?
Natural sources include radioactive rocks, soil compounds, radon gas, food, water, and cosmic rays.
37
What is the largest natural contributor to background radiation?
Radon gas, produced by radioactive rocks, is the largest natural contributor to background radiation.
38
What is the largest source of artificial background radiation?
Medical procedures are the largest source of artificial background radiation.
39
What is a Geiger–Müller tube?
A Geiger–Müller tube is a device that detects alpha, beta, and gamma radiation, producing a 'click' sound and recording a digital count.
40
How is the rate of radioactive decay measured?
The rate of radioactive decay is measured by count rate, which is the number of emissions of radiation in a certain time, typically in units of counts per second (count/s) or counts per minute (count/min).
41
What are the proportians of the sources of radiations?
42
What are some naturally radioactive materials mentioned?
Some rocks and soil compounds ## Footnote These materials can be used in buildings.
43
What is the largest natural contributor to background radiation?
Radon gas ## Footnote Produced by radioactive rocks.
44
Where can radon gas build up to create a problem?
In cellars or mines
45
What makes the food we eat radioactive?
It absorbs radioactive nutrients from the ground
46
Can water contain radioactive materials?
Yes, it can contain mildly radioactive minerals
47
What is another source of natural radiation?
Cosmic rays
48
How is cosmic radiation produced?
Deep in space
49
Why is cosmic radiation more dangerous at high altitudes?
Because some of it can penetrate our atmosphere and reach us
50
What is the largest source of artificial background radiation?
Medical procedures
51
What are other sources of radiation mentioned in the environment?
Nuclear accidents and testing of nuclear weapons
52
Fill in the blank: Radon gas can build up _______.
underground
53
True or False: The food we eat does not absorb radioactive nutrients.
False
54
Fill in the blank: Cosmic rays can penetrate our _______.
atmosphere
55
What is the name for radiation with enough energy to strip away electrons from atoms?
Ionising radiations, such as nuclear radiation, produce ions as they interact with atoms.
56
A radioactive source is known to have a true activity of 400 counts/s, the background radiation is 12 counts/s. Work out the reading in counts/s you would expect from a Geiger–Müller tube.
The reading on a Geiger–Müller tube would be the count rate from the source plus the background radiation. Therefore, it's 412 counts/s
57
What is radioactivity?
Radioactivity is the process by which an unstable nucleus becomes more stable by emitting radiation, such as an alpha particle, beta particle, or gamma radiation. The emission of radiation is spontaneous and occurs in a random direction.
58
What is an alpha particle?
An alpha particle is made up of two protons and two neutrons, giving it a total mass of 4 and a charge of +2. It is highly ionising and is a helium nucleus. It's symbol is:
59
What is the penetrating ability of alpha particles?
Alpha particles are the least penetrating of all radiation types, traveling about 5 cm through air and being stopped by materials such as thin paper or skin.
60
What is a beta particle?
A beta particle is a high-energy electron with almost no mass (relative mass = 1/2000) and a charge of -1. It is only mildly ionising.
61
What is the penetrating ability of beta particles?
Beta particles can travel through skin but are stopped by a few millimeters of aluminum.
62
What are gamma emissions?
Gamma emissions are electromagnetic waves of very high frequency and energy. They have no mass and no charge, making them weakly ionising.
63
What is the penetrating ability of gamma emissions?
Gamma emissions are the most penetrating of the three types of radiation and can only be stopped by thick lead or concrete.
64
What are the ionising effects and penetrating abilities of alpha, beta, and gamma emissions?
Alpha particles have a strong ionising effect and weak penetrating ability. Beta particles have a mild ionising effect and mild penetrating ability. Gamma emissions have a weak ionising effect and high penetrating ability.
65
What types of waves are gamma emmisions?
electromagnetic waves
66
Fill in the blank: Gamma emissions are of very _ frequency and have very _ energy
Gamma emissions are of very high frequency and have very high energy
67
Compare the ionising effect and penetrating abilities of radioactive emmisions.
68
What happens to the nucleus during alpha particle emission?
The nucleus loses two protons, reducing the atomic number by two.
69
What effect does alpha particle emission have on the identity of the element?
The nucleus now represents a different element.
70
What is the process of beta emission?
## Footnote Inside the nucleus, the change is: neutron → proton + electron That means there is one more proton in the nucleus than there was originally and a different element has formed.
71
72
What effect does gamma radiation have on the atomic number?
Gamma radiation does not increase or decrease the number of protons (atomic number) ## Footnote This means the element remains unchanged.
73
What happens to the nucleus after gamma emission?
The nucleus is identical before and after a gamma emission ## Footnote This indicates that gamma emission does not alter the nucleus.
74
What must be true for nuclear decay equations?
Both sides have to balance ## Footnote This includes considering what was present before and after decay.
75
What must equal total mass before and after decay?
Total mass before decay must equal total mass after decay ## Footnote This principle applies to both mass and proton number.
76
What happens when the proton number changes during decay?
A different element is formed ## Footnote This signifies a transformation in the atomic identity.
77
Write the equation of a carbon - 14 undergoing beta decay.
## Footnote The electron has a -1 proton, to ensure the no. of protons in the product is equal to the original components.
78
Write the equation of argon - 40 emiting a gamma ray.
79
Write the equation of Rn - 219 undergoing alpha decay.
80
Summarise what the various decay emissions emit.
## Footnote This image was taken from a video within Kognity. Hopefully that explains the weirdness of the image.
81
Compare the sizes of the decay emissions.
## Footnote Gamma rays have no size as they are pure energy!
82
What are the two definitions of a half - life?
- Half-life is the time taken for the count rate of a radioactive source to decrease by half. - Half-life is the time taken for the number of radioactive nuclei to decrease by half.
83
How can the half-life be represented?
In decay curves. ## Footnote To find an accurate half-life from a decay curve, it is better to measure the time taken for three half-lives and then divide this value by three. Your average reading will then be more accurate, with fewer errors.
84
Describe this half-life's decay curve.
85
The mass of a radioactive isotope is 32 g. After 12 years, the mass of the radioactive isotope is 2 g. What is the half-life of the isotope in years?
86
What does irradiated mean?
When something is exposed to ionising radiation (the irradiated object does not become radioactive).
87
What are the three types of radiation discussed?
Alpha, beta, and gamma radiation
88
What is the primary use of beta or gamma radiation in food processing?
To kill bacteria and increase the shelf life of fresh food
89
How do alpha particles function in smoke detectors?
They ionise the air, allowing current to flow; smoke absorbs alpha particles, reducing current and sounding the alarm
90
What is the penetrating ability and ionising effect of beta particles?
Mildly penetrating and mildly ionising
91
What application uses beta radiation to control material thickness?
Testing and controlling the thickness of materials
92
What is the penetrating ability of gamma radiation?
Highly penetrating but weakly ionising
93
What are gamma rays used for in medical applications?
As medical tracers to detect areas in the body and in cancer treatment
94
Fill in the blank: Gamma rays can also be used to _______ medical instruments.
sterilise
95
What is necessary for a gamma ray source used in sterilisation?
A long half-life
96
What are the potential effects of ionising radiation on humans?
Cancer, radiation burns, mutations, and death
97
What is the half-life of polonium-210, and why is it significant?
Very long; it continues to irradiate the body over time
98
What is the advantage of using medical tracers with a short half-life?
They expose the patient to fewer individual decays, reducing cell damage risk
99
True or False: Pilots are only allowed a set number of flying hours a year due to cosmic rays,
True
100
What protective gear do radiation workers typically wear?
Radiation badges, lead vests
101
What must be worn when handling alpha particle sources?
Protective clothing
102
How should beta particle sources be stored?
In a lead or similarly dense metal container
103
What is required to stop gamma radiation?
Thick lead or concrete
104
What is one method to reduce exposure to radioactivity?
Reducing exposure time, shielding, increasing distance
105
Fill in the blank: The less time a person is exposed to a radioactive isotope, the _______ emissions they experience.
fewer
106
What is the purpose of placing a barrier between a person and a radioactive source?
To provide effective protection against radiation
107
How does increasing distance from a radioactive source affect radiation intensity?
It reduces the intensity of radiation experienced
108
What should you consider when choosing a type of radiation for specific applications?
Ask yourself the following questions: * Do we need the radiation to fully penetrate or indicate variable penetration? * Should it be strongly ionising or not?
109
What types of radiation are mentioned for specific applications?
Alpha particles, beta particles, and gamma rays
110
True or False: Gamma rays are known for their strong ionising capability.
False
111
Fill in the blank: Alpha particles, beta particles, and _______ are types of radiation considered for applications.
gamma rays
112
What does it mean for radiation to be 'strongly ionising'?
Capable of damaging cells or charging particles
113
When evaluating radiation for applications, what is one aspect of penetration to consider?
Whether it needs to fully penetrate or indicate variable penetration
114
Fill in the gap: Gamma with a __ half-life is used for food sterilisation.
Gamma with a long half-life is used for food sterilisation.
115
Fill in the blank: Gamma with a _ half-life is used for medical tracers.
Gamma with a short half-life is used for medical tracers.
116
What are the four precautions to take when dealing with radioactive substances?
117
Describe the emission of radiation regarding direction and time.
The emission of radiation is spontaneous and in a random direction.
118
Define radioactive decay.
Radioactive decay is a change in an unstable nucleus.
119
The frequency of radiation emitted in counts/s is called __ rate.
The frequency of radiation emitted in counts/s is called count rate.
120
A radioactive source is to be used to detect whether cereal packets have been filled to the top as they pass on a conveyer belt. Which type(s) of radiation are suitable for performing this task?
Beta particles are the only type of radiation that would show a measurable difference depending on whether the cereal packet was full or not. Alpha particles will not pass through the box and gamma rays will penetrate the box and the cereal.
121
The half-life of a radioactive sample is 10 hours. A sample is tested and found to have a count rate of 12 counts per second. For the same sample, calculate what the count rate would have been 40 hours ago.
40 hours equals 4 half-lives. So, working back from the current count rate: 12 counts per second goes to 24 24 goes to 48 48 goes to 96 96 goes to 192 counts per second
122
A scientist is investigating a new radioactive source. A Geiger counter placed 3 metres from the source shows a much higher reading than normal. The scientist says: ‘I can find out if this source is an alpha particle emitter by holding a piece of paper in front of the Geiger counter and seeing if the count rate decreases.’ Why is the scientist wrong?
The scientist is correct that alpha particles cannot pass through paper; however, they are also unable to pass through more than a few centimetres of air. So even if this radioactive source is an alpha emitter, the alpha particles will not reach the Geiger counter 3 metres away – whether or not there is a piece of paper in the way.
123

Z: Physics - Yr 10 (3 decks)

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