Atoms and radiation Flashcards
mass of a proton
1
mass of a neutron
1
mass of an electron
very small, practically 0
What is radiation
Anything coming from the nucleus
What are the 3 forms of radiation
Alpha, Beta and Gamma
How is radiation measured
Geiger counter
What was found from the Rutherford experiment
1/ Most of the atom is empty space
2/ There is a positive center to the atom
3/ The positive center is very dense
How do they know most of the atom is empty space
Most alpha particles passed straight through the gold foil
How do they know There is a positive center to the atom
Some alpha particles passed through but were deflected by varying amounts
How do they know That the positive center is very dense
Very few came straight back
What are two examples of radioactive elements
Uranium & Plutonium
Alpha radiation is composed of what
a helium nucleus
What is beta radiation
Electron fired from the nucleus
What is gamma radiation
Electromagnetic wave
What is the range of an alpha particle
Few cms
What is the range of a beta particle
About a metre
What is the range of gamma radiation
Potentially unlimited
What is alpha radiation absorbed/stopped by
Paper / Skin
What is beta radiation stopped by
few mm of aluminum
What is gamma radiation stopped by
Few cms of lead / few feet of concrete
State the order of deflection in a magnetic field, first being most deflected
1/ Beta
2/ Alpha
3/ Gamma
In beta decay what happens to one neutron
One neutron is converted into a proton
When noting beta radiation, what is wrote where the proton number is
The charge (which in an electron is -1)
What measurement can you make in radioactive substances
The amount of time it takes for the number of radioactive nuclei to go down by a half (half life)
What measurement cant you make in radioactive substances
Which nuclei will be emitted next
What is the most ionising radiation
Alpha
How does alpha ionise
They knock electrons away to make the atom positive
Why is beta radiation less powerful at ionising than alpha radiation
Because beta radiation is much much smaller, and therefore less likely to hit
Why is beta radiation more likely to ionise atoms
Have a much further range and therefore chances are increased
Why is gamma the least likely
Because its simply an energy wave
Why arent alpha radiation particles a problem outside the body
They cannot get it
Why are alpha particles dangerous inside the body
They have lots of ionising power
What are the uses of gamma radiation ( 3 )
1/ Sterilisation
2/ Kill cancer cells (radiotherapy)
3/ Tracers
What are the uses of alpha radiation ( 2 )
1/ Controlling paper thickness
2/ Smoke alarms
What are the uses of beta radiation ( 1 )
1/ Controlling foil thickness
What are the uses of general radiation ( 1 )
Radioactive dating
How is it made sure paper is the correct thickness
Firing alpha particles at the paper
How do we know paper is the correct thickness
A few particles get through
Why is it important tracers have short lives
Because we want it in the body for as short as possible
