Atoms & radiation (seneca) Flashcards
During Rutherford’s experiment, —– alpha particles passed straight through the foil.
most
During Rutherford’s experiment, some particles …
bounced back towards the source.
During Rutherford’s experiment, the large deflections suggested that …
some positively charged mass in the atom was repelling the particles.
In ——- , an English physicist called J. J. Thomson discovered electrons.
1897
In 1897, —————————– discovered electrons.
an English physicist called J. J. Thomson
In 1897, an English physicist called J. J. Thomson discovered …
electrons.
In —–, Ernest Rutherford discovered that alpha particles could bounce back off atoms.
1909
In 1909, ———- discovered that alpha particles could bounce back off atoms.
Ernest Rutherford
In 1909, Ernest Rutherford discovered that …
alpha particles could bounce back off atoms.
———– discovered that electrons orbit (fly around) the nucleus at fixed distances.
Niels Bohr
Niels Bohr discovered that …
electrons orbit (fly around) the nucleus at fixed distances.
In ———, James Chadwick discovered that some particles in the nucleus have no charge at all. He called them neutrons.
1932
In 1932, —————— discovered that some particles in the nucleus have no charge at all. He called them neutrons.
James Chadwick
In 1932, James Chadwick discovered ———————————. He called them neutrons.
that some particles in the nucleus have no charge at all
In 1932, James Chadwick discovered that some particles in the nucleus have no charge at all. He called them …
neutrons.
When atoms absorb electromagnetic radiation, electrons move to a …
higher energy level further away from the nucleus.
When atoms emit electromagnetic radiation, electrons can …
drop to a lower energy level, closer to the nucleus.
The number of protons in a nucleus tells us what …
element an atom is.
The mass number is the …
total number of protons and neutrons in a nucleus.
Hydrogen has 3 different isotopes:
- Protium
- Deuterium
- Tritium
Protium is a hydrogen atom with …
1 proton and 0 neutrons.
——– of hydrogen atoms are protium.
99.98%
Protium used in …
hydrogen fuel cells and the production of plastics
Deuterium is a hydrogen atom with …
1 proton and 1 neutron.
Around —— of hydrogen atoms are deuterium.
0.02%
Deuterium is used in…
nuclear fusion.
Tritium is a hydrogen atom with …
1 proton and 2 neutrons.
Tritium is …
very rare.
Tritium is used in …
thermonuclear fusion weapons.
Isotopes are forms of an element that …
have the same number of protons, but a different number of neutrons.
A nuclide is a type of …
isotope.
A nuclide refers to …
a specific nucleus that contains a certain number of protons and neutrons.
Nuclides of the same element have:
- different nucleon numbers
- the same proton number
- the same number of electrons
An electron can move to a
——- energy level by absorbing electromagnetic radiation.
higher
An electron can move to a
higher energy level by …
absorbing electromagnetic radiation.
An electron can move to a lower energy level by …
emitting electromagnetic radiation.
An electron can move to a —– energy level by emitting electromagnetic radiation.
lower
Substances that decay radioactively are “—————”.
radioactive substances
We cannot predict when an individual atom will …
emit (produce) ionising radiation.
An unstable nucleus can become more stable over time by …
randomly (spontaneously) emitting ionising radiation.
An unstable nucleus can become more stable over time by randomly (spontaneously) emitting ionising radiation. This process is called …
radioactive decay.
Substances that decay radioactively are “———————-”.
radioactive substances
Alpha radiation is produced by…
alpha decay
Alpha radiation releases …
helium nuclei
Beta radiation is produced by…
beta decay
Gamma radiation is produced by…
gamma decay
Gamma radiation is a …
high-energy electromagnetic wave with a higher frequency than X-Rays.
What are beta particles?
electrons
Alpha radiation is a …
helium nucleus
Gamma radiation is an …
electromagnetic wave produced by gamma decay.
Neutrons are also type of …
radiation
Nuclei can become more stable by …
decaying.
Nuclei can become more ——- by decaying.
stable
In radioactive decay, we cannot predict when an individual atom will emit (produce) ———- radiation.
ionising
How is radioactive decay triggered?
it is spotaneous
There are three primary ways of detecting radioactivity:
- Cloud chamber
- Photographic film
- Geiger counter (Geiger-Muller tube)
A cloud chamber is a …
container full of air containing alcohol vapour.
In a cloud chamber, ionising radiation enters the …
air and leaves a trail of ionised air molecules.
In a cloud chamber, the alcohol vapour …
condenses on the ionised air molecules, showing the trail of radiation.
In photographic film, ionising radiation has the same effect on photographic film as …
light.
In photographic film, a bright spot appears wherever the …
ionising radiation hits the film.
In Geiger counter (Geiger-Muller tube), ionising radiation enters a…
tube full of low-pressure gases.
In Geiger counter (Geiger-Muller tube), it ionises the …
atoms in the gas, knocking electrons out of the atoms.
In Geiger counter (Geiger-Muller tube), the gas can now …
conduct electricity and completes an electric circuit. Current flows between electrodes.
In Geiger counter (Geiger-Muller tube), current produces a …
clicking noise.
The count-rate is the …
number of decays recorded each second.
Radon is a …
gas that emits alpha particles.
———– is a gas that emits alpha particles.
Radon
If we breathe in alpha particles, alpha radiation will …
reach our lung tissue.
The sun emits some…
ionising radiation.
Fruits high in potassium, like bananas, are …
very slightly radioactive.
Rocks like granite contain small amounts of …
uranium salts.
Sources of background radiation:
- foods
- radon gas
- rocks
- the sun
Each alpha particle contains …
two protons and two neutrons.
Each alpha particle contains two protons and two neutrons.
Because of this, alpha particles have a relative mass of …
4.
Because the particles are ———————-, alpha radiation is strongly ionising.
big and heavy
Because the particles are big and heavy, alpha radiation is …
strongly ionising.
Alpha particles does a lot of damage but is stopped by a …
small amount of matter (like paper).
Alpha particles does ————- but is stopped by a small amount of matter (like paper).
a lot of damage
Beta radiation is made up of …
high-energy electrons.
Beta radiation is more ionising than 1. but less ionising than …
- gamma radiation
- alpha radiation.
Beta radiation can pass through 1. but is stopped by 2.
- paper
- aluminium foil.
Gamma radiation is ——– ionising.
weakly
Gamma radiation does less damage than 1. , but it is stopped only by 2.
- beta or alpha radiation
- centimetres of lead or meters of concrete.
Alpha radiation is like a …
bull running into a hedge. It does lots of damage to the hedge but doesn’t get through very far.
Beta radiation is somewhere between the other two (alpha & gamma), like a …
cat running through the hedge.
Gamma radiation is like a …
bird flying into the hedge.
It can dodge between the branches for a while, but will eventually get stuck.
Which is the most penetrating type of radiation?
gamma radiation
We can use gamma radiation to …
sterilise medical equipment in hospitals. Sterilisation kills bacteria and viruses.
A radioactive material fires ————- at a smoke detector.
alpha particles
If there is smoke between the radioactive material and the smoke detector, then …
This will set off the smoke alarm.
fewer alpha particles will reach the detector.
If we put a gamma-emitting isotope into a patient’s body, we can …
trace (follow) the radiation’s movement around the body.
Gamma radiation is the most penetrating type of radiation. This means it can 1.
This means gamma can 2.
- pass through objects more easily than alpha or beta radiation.
- leave the body without creating too much damage (ionisation).
Gamma radiation also has a ——- half-life. This means that the radiation vanishes quickly.
short
Gamma radiation also has a short half-life. This means that the radiation …
vanishes quickly.
We can fire beta particles through paper in a factory to …
make sure that the paper being produced is the right thickness.
We can fire beta particles through paper in a factory to make sure that the paper being produced is the right thickness.
If the thickness of the paper changes,
greater or fewer beta particles will reach the detector. Production can then be stopped.
How is blood flow in the body imaged using radiation?
- Gamma-emitting isotopes are injected into the body.
- We can trace the gamma-emitting particles as they travel in the blood around the body.
- We can use the detected signal to image the organs in the body.
How does a smoke detector work?
- A radioactive material fires alpha particles at a smoke detector.
- If there is smoke between the radioactive material and the smoke detector, then fewer alpha particles will reach the detector.
- This will set off the smoke alarm.
Nuclear fission splits 1 nucleus into …
2 or more smaller nuclei.
Nuclear fission splits 1 nucleus into 2 or more smaller nuclei. It usually happens in …
nuclear reactors.
During fission, a —— collides with a large nucleus and is absorbed. This creates an unstable nucleus.
neutron
During fission, a neutron collides with a large nucleus and is absorbed. This creates …
an unstable nucleus.
During fission, a neutron collides with a —————– and is absorbed. This creates an unstable nucleus.
large nucleus
During fission, after the nucleus splits into fragments there is a release of …
large amounts of energy and more neutrons.
During fission in a nuclear reactors, the energy released is used to 1. The turbine then 2.
- boil water, which rotates a turbine.
- turns a generator, which produces electricity.
If nuclear fission is not controlled, then the rate of nuclear fission can become …
faster and faster.
If nuclear fission is not controlled, then the rate of nuclear fission can become faster and faster. This starts a chain reaction where each stage of fission produces more and more energy. This could lead to …
an explosion.
Atom bombs use these chain reactions to create …
large explosions and release lots of energy.
What kind of reaction happens during nuclear fission?
chain reaction
Nuclear fusion…
fuses (joins) 2 smaller nuclei to create 1 larger nucleus.
Nuclear fusion fuses (joins) 2 smaller nuclei to create 1 larger nucleus. Creating this larger nucleus releases …
energy.
Hydrogen bombs use ————- to release lots of energy in an explosion.
nuclear fusion
Stars generate their energy from the …
fusion of hydrogen and helium nuclei.
Scientists have tried to create sustainable energy using nuclear fusion.
This is difficult as hydrogen must be heated to over …
100 million °C.
Scientists have tried to create sustainable energy using nuclear fusion.
This is difficult as ———– must be heated to over 100 million °C.
hydrogen
In fusion we use the —————— as it does not require as much energy as bigger atom would diffuse.
smallest atoms we can get
In fusion we use the smallest atoms we can get as …
it does not require as much energy as bigger atom would diffuse.
During alpha, beta, and gamma radioactive decay, an unstable nucleus becomes more …
stable.
Which form of decay doesn’t create a new element?
gamma decay
The sum (total) of the atomic numbers on one side of the equation must equal …
to the sum (total) of the atomic numbers on the other side.
How many nucleons are lost in alpha decay?
4
In nuclear fission, the number of ——————- , but 4 nucleons are released to continue a chain reaction with other atoms.
protons remains the same
In nuclear fission, the number of protons remains the same, but …
4 nucleons are released to continue a chain reaction with other atoms.
In nuclear fission, 1 atom decays to form…
two new atoms and some neutrons (sub-atomic particles).
Which isotope of uranium is used in nuclear fission?
Uranium-235
How many protons and neutrons are lost in alpha decay?
2 protons
2 neutrons
In alpha decay, 4 nucleons are lost in the form of an alpha particle. 2 protons are lost so the initial atom becomes …
a different element.
The half-life is the …
average time taken for the number of radioactive nuclei to halve.
The half-life for any isotope of an element is …
constant.
The half-life of unstable isotopes can be …
seconds or millions of years.
The radioactive decay of an individual atom is …
random and unpredictable.
Large groups of nuclei do normally behave in ————— ways.
predictable
To find the half-life of an isotope, measure the …
time taken for the activity of the sample to halve.
To find the half-life of an isotope from a graph or table, measure the …
time that it takes for the radioactive count rate or the number of unstable nuclei to halve.
How would you measure count rate to work out a substances half-life?
using a Geiger counter.
Ions can react in ———– ways.
unusual
Ions can react in unusual ways.
This can damage …
cells and complex chemical structures, such as DNA.
The cell damage from ionising radiation can cause 1. These 1. can lead to 2.
- mutations
- cancer and organ failure
Ions are …
particles that become charged by gaining or losing electrons.
Alpha, beta and gamma radiation are all
———- radiation.
ionising
Ionising radiation can break molecules into small particles called …
ions
Radioactive sources (materials) should not be handled …
directly and should only be used for the shortest time possible.
We should use 1. when handling ionising radiation and 2.
- rubber gloves
2.
Radioactive sources (materials) should be stored in …
lead-lined boxes and locked in steel cabinets away from people.
We should not ————- when using a radioactive source.
eat or drink
Sources should be kept at ———– and we should not put them in our pockets.
arm’s length
Sources should be kept at arm’s length and we should not put them in …
our pockets.
Types of nuclear safety precaution:
- usage
- reduce exposure
- storage
- handling
We should minimise our exposure to sources, use …
shielding and maximise the distance between the user and the source.
Iodine-123 has a half-life of …
13.2 hours.
Iodine-123 has a half-life of 13.2 hours. This makes it suitable for …
treating cancerous cells.
Because its half-life is so short, Iodine-123 doesn’t do …
much damage to healthy cells after the treatment is done.
Iodine-131 has a half-life of …
8 days.
Iodine-131 has a half-life of 8 days. This means it can be used in …
medical tracers to see how well the thyroid gland is working.
Iodine-131 has a long enough half-life for us to …
monitor (watch) how well the gland is functioning (working) over a good period of time.
Iodine-131 has a long enough half-life for us to monitor (watch) how well the gland is functioning (working) over a good period of time.
At the same time, the
amount of harm caused is limited as the patient does not need to receive extra doses.
Radiotherapy can …
kill cells and destroy tissue inside the body.
In radiotherapy, high doses of radiation can …
kill mutated cells (cancers), but the radiation can also kill healthy cells.
What are the disadvantages of radiotherapy?
- The radiation may also kill healthy cells. If lots of cells are killed at once, this can cause radiation sickness.
- Even small doses are likely to kill some healthy cells, so patients experiencing radiotherapy often feel very unwell.
What are the advantages of radiotherapy?
In radiotherapy, high doses of radiation can kill mutated cells (cancers).
This can lead to a longer, healthier life.
Why would we use radiation with a long half life in medical treatment?
To track its path through the body over time.
Objects near to radioactive sources are ———– by them.
irradiated
Contamination is when …
radioactive substances occur from inside something.
Irradiation is when …
something is exposed to radiation on its outside.
Irradiation is simply …
exposure to nuclear radiation.
When a radioactive source irradiates an object, the object does not become …
radioactive.
We can reduce irradiation by …
standing behind lead or storing radioactive material in lead-lined boxes.
Radioactive contamination is when …
radioactive atoms or molecules get onto other materials.
Contamination is harmful because …
contaminating atoms decay.
How harmful the contamination is, depends on …
the type of radiation the atoms emit.
Contaminated atoms are likely to continue to decay. This could harm you if …
this happens on your skin.
Alpha is the most dangerous form of …
radiation inside the body.
Alpha radiation cannot penetrate (pass through) the skin so, …
it stays in the body.
Gamma is the ———– harmful radiation.
least
Gamma radiation is the most penetrative (passes through things ,such as skin, most easily), and so it will
easily pass out of the body.
Beta is not very harmful as it can …
pass out of the body.
Which type of contamination/radiation is most likely to cause cell mutations?
alpha
It’s important for scientists to share their research on radiation and its effects. Scientists can check each other’s work. This is called …
peer review.
What does the nucleon number refer to?
Total number of protons and neutrons in a nucleus
What do we call the process of an unstable nucleus randomly emitting ionising radiation to become more stable?
radioactive decay
Which type of ionising radiation results in the emission of helium nuclei?
alpha radiation
What is radioactive decay?
An atom can have an unstable nucleus. An unstable nucleus can become more stable over time by randomly and unpredictably emitting ionising radiation. This process is called radioactive decay.
In order to determine the half-life of a radioactive isotope from a graph depicting radioactive decay, what should be the first thing that you check?
If the background radiation is accounted for.
level of radiation with substance and background radiation - level of background radiation. =
The level of radiation due to substance
The level of radiation due to substance =
level of radiation with substance and background radiation - level of background radiation.
The half-life is the …
average time taken for the number of radioactive nuclei to halve.
Alpha is the most dangerous form of radiation
——— the body. It is the most ionising type of radiation.
inside
————————- radiation can enter the body through the skin as they are more penetrative than alpha radiation.
Gamma and Beta
