Atom Structure

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  • Created by: leo1223
  • Created on: 07-05-18 10:41
What is an alpha particle also know as?
An alpha particle is also know as a helium nucleus as it has two neutrons and two protons
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How does alpha decay affect an atom's mass, charge and atomic number?
Once an alpha particle is emitted the atomic number decreases, it does not affect the charge of an atom, the mass number decreases by four, therefore a new element is formed
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How does beta decay affect an atom's mass, charge and atomic number?
Once a beta particle is emitted the atomic number increases by one, the charge of the atom is affected by +1 as they is one more proton, the mass number is unchanged, therefore a new element is formed
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Explain the process by which an atom decays by alpha decay?
If a nucleus has too few neutrons, it will emit two protons and two neutrons know as a alpha particle in order to become stable
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Explain the process by which an atom decays by beta decay?
If a nucleus has too many neutrons, a neutron will turn into a proton and a electron will be emitted from the nucleus, this electron is know as a beta particle
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Describe the three features of a gamma ray?
Gamma rays are very high-energy electromagnetic waves that have no charge and no mass
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How do gamma rays affect an atom's mass, charge and atomic number?
The emission of gamma rays does not cause the mass, atomic number and charge to change
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Define background radiation?
Background radiation is ionising radiation that is around us all the time
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What is the penetrating power of gamma rays?
Gamma rays are the most penetrating type of ionising radiation, they are able to penetrate several meters of concrete and several centimetres of lead
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What is the penetrating power of beta particles?
Beta particles are able to penetrate a few meters of air but can be stopped by aluminium about 3mm thick
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What is the penetrating power of alpha particles?
Alpha particles are the least penetrating type of ionising radiation, they are able to penetrate a few centimetres of air or sheets of paper before they are stopped
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Define half life
The half life of a radioactive isotope is the average time it takes for half the nucleus to decay
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Define count rate
Count rate is the number of decays recorded each second
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How can a isotope change into a new element?
By emitting alpha or beta particles
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Define the term irradiation?
Irradiation is when objects are exposed to radiation, typically cobalt 60. The gamma rays emitted by the cobalt kills any bacteria on the fruit. This process does not cause the fruit to become radioactive
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Describe the process of using irradiation for sterilisation?
Irradiation can be used to sterilise food such as fruit and medical instruments by allowing gamma rays to irradiate the object. The process kills all bacteria in the process and does not cause the object to become radioactive
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How is irradiation used to kill cancerous tumours?
Gamma rays can be used to kill the cancerous tumours, these beams are aimed at the tumour from many different directions which maximises the effect while reducing the amount of healthy tissue affected. This technique can damage healthy tissue
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What three considerations should be made when using radioactive sources for either medical or industrial processes?
The nature of decay (alpha, beta or gamma rays), the half life as it must be long enough to carry out the process but short enough to decay safely after its use, the toxicity
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Name all the advantages irradiation?
Sterilisation can be done without high temperatures needed to kill of bacteria, this saves energy and money, It can also be used to kill bacteria on objects that would melt at high temperatures
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Name all the disadvantages of irradiation?
It may not kill all the bacteria on a object, it has the potential to do harm, it cause mutations and damage cells if people are in the surrounding area
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What is radioactive contamination?
Radioactive contamination is the unwanted presence of materials containing radioactive atoms
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What three factors affect the level of contamination?
Penetrating power of the radiation, it's ionising power and the isotopes half life
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What is a medical tracer?
A medical tracer is a radioisotope that is put into the body, either by injection or consumption
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Name two uses of medical tracers
Monitor the functions of internal organs, check for a blockage in a patient's blood
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How do radioactive tracers work?
Tracers move around the body in the patients blood. As the tracer emits radiation, which allows where the blood flows to be monitored. Therefore blockages in the blood flow can be detected.
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Why can medical tracers cause further harm to a patient and how can this be stopped?
If the tracer remains the body longer that it is required to, it would continue to damage the cells due to its radioactivity. Therefore it is important that tracers with short half lives are used
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Name 3 uses of X-rays and gamma rays?
Both are able to diagnose problems and treat them, can be used to explore internal organs and bones, and to control or destroy cancerous cells
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What is the main difference between gamma rays and X-Rays?
Gamma rays are emitted by isotopes where as X-Rays are produced by X-Ray machines
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Name 3 requirements that radioisotopes must meet in order to be used for medical purposes
They must mainly emit gamma rays, should have a suitable half-life, must not be toxic to humans
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Explain what radiotherapy is?
Radiotherapy is the process of cancer cells being destroyed by exposing the affected area with large doses of radiation.
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Name 3 advantages X-Rays have over Gamma rays?
X-Rays are only produced when needed, the rate of production of X-Rays can be controlled, The energy of X-Rays can be changed
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What two techniques are used to protect healthy tissue during radiotherapy?
The source is slowly rotated around the patient with the tumour at the centre of the circle, the source is used in three different directions around the area, both decrease the amount of healthy tissue destroyed by radiotherapy
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What is Brachytherapy?
In Brachytherapy a small sealed radioactive source is placed in the tumour itself, which gives a high dose to the tumour and a lower dose to the surrounding tissue.
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What side effects does nuclear radiation cause cancer patients?
Vomiting, reddening and pain in skin, greater risk of infection and tiredness
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What are the disadvantages of nuclear radiation as a cancer treatment?
Nuclear radiation can cause further cancers, serve side effects, damages lots of healthy tissue
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What are the advantages of nuclear radiation as a cancer treatment?
Nuclear radiation enables the exploration of internal organs through the use of a tracer, it is able to destroy cancerous cells
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How can the risk of a treatment be evaluated?
By considering the radiation dosage
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What is nuclear fission?
Nuclear fission is when a large unstable nucleus, splits into two daughter nuclei when it absorbs a neutron, creating two new elements, three neutrons are released which releases lots of energy in the form of kinetic energy and gamma rays
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Explain how nuclear fission can occur without the absorption of a neutron?
Spontaneous fission can occur however this is very rare
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Explain what neutron radiation is?
Neutron radiation is release of a high speed neutron as a product of nuclear fission
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How is a chain reaction caused by one nucleus splitting?
The extra neutrons emitted can split more nuclei into two daughter nuclei which is know as a chain reaction as each neutron released causes the fission of another nucleus
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What is controlled fission used for?
Controlled fission is used for nuclear power stations, uranium is used
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What happens in a nuclear reactor?
The fission of uranium in a nuclear reactor starts the chain reaction which produces a supply of thermal energy
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What is nuclear fusion?
Nuclear fusion is the joining of small light nuclei such as hydrogen and helium to form a heavier nucleus. This produces energy
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Where and how is nuclear fusion used?
In stars, hydrogen nuclei fuse at extremely high pressures and temperatures to produce helium nuclei
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What conditions are required for nuclear fusion?
The required conditions for nuclear fusion are high temperatures and pressures
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If it was possible to complete fusion on earthWhy would it be preferred over fission as an energy source?
It would be preferred to fission as an energy source as there is plenty of hydrogen for fusion and the waste products (helium) are not radioactive
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Other cards in this set

Card 2

Front

How does alpha decay affect an atom's mass, charge and atomic number?

Back

Once an alpha particle is emitted the atomic number decreases, it does not affect the charge of an atom, the mass number decreases by four, therefore a new element is formed

Card 3

Front

How does beta decay affect an atom's mass, charge and atomic number?

Back

Preview of the front of card 3

Card 4

Front

Explain the process by which an atom decays by alpha decay?

Back

Preview of the front of card 4

Card 5

Front

Explain the process by which an atom decays by beta decay?

Back

Preview of the front of card 5
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