Radiation Flashcards
How does radioactive decay occur
When the nucleus of an atom becomes unstable and starts to break down emitting a radioactive particle
Handling radioactive materials
Store in a led lined container
Use tongs to keep as far away as possible
Point the material away from yourself and the people around you
Limit the time you spend with it
What was the plum pudding model
A cloud of positive charge with negative charges dotted throughout
Explain Rutherford’s experiment
Alpha particles were directed towards a thin metal sheet of gold foil . The alpha particles were first passes through 2 lead slits to create an approximate parallel beam
Conclusion of the experiment
The atom is mainly made of empty space
It contains a central mass which is bigger than a single particle
The nucleus contains a positive charge
Results of the experiment
Large number of alpha particles passed through with little to ho defection
Some however did be reflected and at times a whole 90 degrees
What is an isotope
An atom of an element with the same amount of protons and therefore electrons but a different amount of neutrons
Why does the unstable nucleus emit a radiation
To decrease it’s high energy state to a much lower and easier to control state
What does an alpha particle add
Two neutrons and two protons therefore its number at the top is
4
And at the bottom is
2
Due to their size they are extremely ionizing
What does the beta particle add
It leaves the mass number at the top the same but changes the proton count at the bottom by one
What stops Gamma rays
One metre of led
What stops beta
2 mm of aluminum
What stops Alpha
A piece if paper of 5 cm of air
What is the half life of a material
The time it takes for half of the radioactive nuclei to decay
It is a random process
What is activity
The number of decays that happen in a second
What is nuclear fission
The splitting of a nucleus to form two smaller nuclei and 2-3 electrons
However not all atoms can undergo fission , if they can they are called fissionable
Nuclear fusion
The fusing of two smaller nuclei a create a single nucleus
Hydrogen is most commonly used for fusion
What is the problem with nuclear fusion
The protons will constantly repel each other therefore a huge amount of energy is required to push them together which costs a fortune
It requires high pressure and a minimum of 5000 kelvin
Specific heat capacity triangle
MassxSHCxtempchange
(Kg). (J/kg). (C)
What is the SHC formula
Energy = mass x SHC x temperature change
(Kg) (J/KG) (C)
Specific heat capacity equals
Change in temp x mass
Change in temperature equals
Mass x SHC
Mass equals
Change in temp x SHC
How did Niels Bohr impact the model of the atom
Said that electrons orbited the nucleus
How did Chadwick impact the model of the atom
Discovered neutrons
Where does background radiation come from
Naturally occurring unstable isotopes around us
Radiation from the sun
Human activity from nuclear waste or explosions
What is irradiation
Objects near a radioactive source are irradiated by it . Meaning that they are exposed to the source
What is contamination
If unwanted radioactive atoms get into or onto the object it is considered contaminated
How is gamma radiation used in medical tracers
Iodine 123 gives out gamma radiation . Medical scanners can then be used to detect where the substance is in the body
Alpha is never used as it is too ionizing
Radiotherapy
Radiation damages all cells . The radiation is directed to the cancer cells however a fair bit of damage is inevitably done to the surrounding normal cells .
