Radiation & Atoms Flashcards
Why does an atom have no overall charge?
It has the same amount of protons and electrons which cancel each other out
What experiment was carried out by Rutherford and marsden - what was it used to show?
The experiment was called the scattering experiment.
An alpha particle was fired at a thin sheet of gold which showed that some travelled through but some reflected back.
This was used to show the modern model of the structure of an atom
What are the 3 types of radiation and what are they made from?
Alpha - helium nucleus 2 protons 2 neutrons
Beta - High energy electron
Gamma - electromagnetic wave
Why are some atoms radioactive?
They have unstable nuclei which give out radiation all the time despite what is done to them
What is an isotope?
An atom with a different amount of neutrons
What effect does alpha decay have on the nucleus of an atom?
Alpha decay is the loss of helium nuclei
the proton number decreases by 2 and mass decreases by 4
How are the 3 types of radiation affected by electric and magnetic fields?
Alpha and beta are deflected
Gamma is not affected
What is half life?
Half life is the time it takes for a radioactive material to break down to half its original radioactivity
Can occur in seconds or millions of years
Which of the 3 types of radiation is the most ionising and why?
Alpha is the most ionising because it is the biggest which causes most damage to atoms
Which is the most penetrative type of radiation out of the 3?
Gamma
What can the 3 types of radiation be stopped by?
Alpha - stopped by paper
Beta - stopped by aluminium foil
Gamma - stopped by thick lead
Which is the most dangerous type of radiation outside of the body?
Gamma because it can penetrate fragile internal organs
What is the most dangerous type of radiation to the inside of the body?
Alpha because it is the most ionising causing most damage to cells
How can radioactive substances be used for medical tracers?
Tracers use gamma radiation because it is less dangerous to the patient and has a short half life so they aren’t radioactive for too long
What is background radiation and where does it come from?
Background radiation is radiation around us all of the time
It comes from space, rocks underground, x Rays etc
