7.) Topic 7 Types Of Radiation Flashcards
What is the proton number (atomic number)
The number of protons in the nucleus
What is the nucleon number (mass number)
This tells us the number of protons and neutrons in a nucleus
If an atom loses an electron what does it become?
A positive ion
If an atom gains an electron what does it become?
A negative ion
How do we work out the number of neutrons in an atom
The mass number - the atomic number
What are isotopes?
The same number of protons in the nucleus, but a different number of neutrons
Why are some atomic nuclei unstable?
Because they have an imbalance of protons and neutrons and therefore too much energy
How can some unstable nuclei become more stable?
ENERGY
By losing some of their energy
What do unstable nuclei emit?
They emit ionising radiation
Why do unstable nuclei emit radiation?
(What do they undergo)
(What happens to their stability)
Unstable nuclei undergo radioactive decay to become more stable
As they release radiation, their stability increases
State the 3 types of nuclear radiation
Alpha radiation
Beta radiation
Gamma rays
What are the constituents of an alpha particle (alpha radiation) ?
It has the same nucleus as helium element
Has 2 protons and 2 neutrons
What are the constituents a beta particle (beta radiation) ?
They are fast moving/high energy electrons emitted from the nucleus
What are the constituents of gamma radiation?
Gamma radiation is very short wavelength, high frequency electromagnetic radiation
What are alpha particles range in air?
Can travel around 5cm in air before they collide with air particles and stop
What are beta particles range in air?
They can reach around 15cm in air before stoppWahing
What are gamma radiation range in air?
They can travel several metres in air before stopped
What are alpha particles penetrating power (what can it be stopped by)
A thin sheet of paper, skin or few cm of air
What are beta particles penetrating power (what can it be stopped by)
Few mm of aluminium or up to a metre of air
What are gamma radiation penetrating power (what can it be stopped by)
Several cm of lead or very thick concrete
What are alpha particles ionising radiation?
What are the 2 things which can happen inside the body if body is prone to alpha radiation
Very high - most damaging inside the bodies
Kill the cells or alter the DNA of the cell, causing it to mutate forming cancer
What are beta particles ionising radiation?
Medium
What are gamma radiation ionising radiation?
Very weakly ionising
Can easily be passed through the body
State any changes to mass or charge that occur due to the emission of a gamma ray
There are no changes
State any changes to mass or charge that occur due to the emission of an alpha particle
Give an example
The atomic number decreases by 2
The mass number decreases by 4
238 U___—> ______234 Th____+____4 He
92 _______________90___________2
State any changes to mass or charge that occur due to the emission of a beta particle
Give an example
The atomic number increases by 1
16 O___—>___16 F____+____0 e
8___________9___________-1
What is radioactive decay?
The process in which unstable atomic nuclei break apart or change, releasing radiation as they do so.
Describe the nature of radioactive decay
what is it possible to predict
Random and spontaneous
It is possible to predict the number of atoms in a population which will undergo decay
What does half life mean?
The time it takes for the number of radioactive nuclei to halve in an isotope
State 2 techniques that can be used when carrying out experimental work, to combat the random nature of decay
Take repeat readings
Carry the experiment out over a long period of time
What can be used to measure ionising radiation and what is the number counted per minute known as
A Geiger counter
Becquerel (Bq)
What are some natural sources of background radiation
Radon, cosmic rays, rocks and living things
What are some man made sources of background radiation
Medical and nuclear industry
Explain how radon gas can be dangerous. Explain the process completely
(Where it is emitted from) (what can decay to form radium) What decays to form radon gas) (where it can enter) (what can it cause) (where can it build up)
Radon is emitted from rocks and the soil. Granite is a radioactive rock because it contains Uranium. The uranium in the granite decays eventually forming radium. After the radium then decays to radon gas. As radon is a gas, it escapes from the granite and is easily breathed into humans. The radon enters our lungs, where it can decay, and the alpha particles emitted by the decaying radon are absorbed by the cells lining the lungs, causing the cells to die or mutate (forming cancers).
Radon gas can build up in houses particularly the ones with poor under-floor ventilation or those made of granite
What are the things you can do to reduce the levels of radon in your house x3
Improve ventilation by opening windows
Fitting air bricks to improve under floor ventilation
Install a fan to extract radon gas from a sump underneath the house
What is radiation measured in?
Sieverts (Sv)
Millisieverts (mSv)
What are 4 ways in which people can be protected from radiation sources
Limiting time - radiation dose is reduced by limiting exposure time
Distance - Intensity of radiation decreases with distance from its source
Shielding - Handled underwater, barriers of lead and concrete give protection from high levels of penetrating radiation such as gamma rays
Containment - Very radioactive materials are confined and kept out of the workplace and the environment.
Nuclear reactors operate within closed systems
What are nuclear power stations used for?
To generate electricity
What is a downside of nuclear power?
Nuclear waste is produced from radioactive material
What are examples of low level nuclear waste and where can it be disposed?
Examples: Contaminated clothing, material and equipment
Disposal: Disposed of in clay-lined landfill sites by surrounded it by concrete in large disposal drums
What are examples of intermediate level nuclear waste and where can it be disposed?
Examples: Radioactive sources used in medicine and components from nuclear reactors
Disposal: By mixing the waste with concrete and putting it in stainless steel drums which are then buried in purpose-built stores
What are examples of high level nuclear waste and where can it be disposed?
Examples: Used nuclear fuels and chemicals from reprocessing fuels (nuclear reactors)
Disposal: Stored underwater in large pools for 20 years, then placed in storage casks in purpose-built underground stores where air can circulate to remove the heat produced. High-level waste decays into intermediate-level waste over many thousands of years.
Exam question
Why are some atoms radioactive?
Their nuclei is unstable - imbalance of protons and neutrons
Exam question
What are 3 ways that nuclei can become more stable
Decay by emitting alpha, beta or gamma radiation
Exam question
What happens to the lungs if someone breathes in radon gas
The alpha particles can ionise the cells of the lungs, causing them to die or mutate
Exam question
What happened to the cells of the parents whose children were born with physical abnormalities
Small genetic mutations in the DNA contained in the sperm or egg cells caused this
Exam question
How are beta radiation and UV light similar
They are both forms of ionising radiation
Exam question
Why is alpha radiation more dangerous than UV light?
Because alpha particles are very ionising so very harmful
Exam question
Why would radioactive sludge be safer it it is placed in encased glass
Sludge will be solidified and cannot leak. The glass will absorb all the alpha radiation and some of the beta radiation emitted by the waste
Exam question
Write the nuclear equation for Uranium-235 (alpha particle emitter) decaying into thorium-231
235 U__—->231 Th___+____4 He
92________90___________2
Exam question
Write the nuclear equation for carbon-14 decaying into nitrogen-14
14 C____—>_______14 N_____+ 0 e
6________________7___________-1
Exam question
Why are radioactive waste storage canisters made out of steel
Because steel doesn’t break easily, keeping the radioactive waste intact
Exam question
What is the purpose of water inside the storage ponds
Water absorbs beta particles and some gamma radiation
Exam question
Why do you think that buildings are made out of thick reinforced concrete and not standard bricks
Because it will absorb some gamma radiation, reducing the amount of radiation emitted by waste
Exam question
Why might it be impractical to shield the entire structures in lead, to substantially reduce the emission of gamma radiation from the buildings
Because lead is very dense, so lead shielding would be very heavy, requiring the structure to be super strong. This would be impractical
How it a beta particle fomed?
A beta particle forms when a neutron changes into a proton and a high-energy electron . The proton stays in the nucleus but the electron leaves the atom as a beta particle
