Atoms And Radiation Flashcards
What is an isotope
Nucleus with the same number of protons but different number of neutrons
If an atom loses an electron what does it become?
Positively charged ion
If an atom gains an electron what does it become
Negatively charged ion
What is the plum pudding model
Atom was imagined to be a sphere of positive charge with negative electrons in it
What was Rutherford’s scattering experiment?
Alpha particles were beamed at gold foil.
Scientists thought they would go through the foil
Some came out at different angles and some came straight back
This showered particles were being repelled and deflected
So the plum pudding model was replaced by the nuclear model of the atom
What is alpha radiation (4)
Consist of alpha particles
2 protons and 2 neutrons
Atoms that emit alpha radiation are big atoms
After emitting an alpha particles, mass and proton numbers decrease
What is beta radiation ? (4)
When a nucleus has too many neutrons
Protons stay in and electrons are emitted as beta particles
Proton number increased by one
Beta consists of high energy electrons
What is gamma radiation?
No protons or neutrons emitted
Only excess energy is emitted
Short wavelength high frequency
How good are the 3 types of radiation at penetrating
Alpha- least penetrating
Beta - penetrate air and paper
Gamma - most penetrating
What can beta radiation be stopped by?
Thin sheet of aluminium
What is half life?
Time taken for the count rate of a sample to halve
What does a short half life mean
Small amount of time a nucleus takes to decay
How does an atom became stable
Emit gamma radiation or particles
WHERE are each of the three types of radiation used?
Alpha - smoke alarms
Beta - paper thickness
Gamma - cancer treatment
What is a good property of alpha?
Great ionisation power
What are the charges of the 3 forms of radiation
Alpha +2
Beta -1
Gamma no charge
Why is alpha the most dangerous to have. In your body
It is easily absorbed by cells. Beta and gamma just pass through
Why are beta and gamma more dangerous outside of the body
It can penetrate skin and damage cells inside
What happens when alpha particles decay?
Two neutrons and protons are lost so
Atomic mass decreases by 4
Atomic number decreases by 2
What is fission
Spilt ting up larger atomic nucleus into 2 smaller nuclei
What are the 4 things that happen in fission
Nucleus splits into 2 smaller nuclei
Two or 3 neutrons are released
Some energy is released
The neutrons that have split split again so reaction continues
Advantages and disadvantages of fission
More energy per kg of fuel
Radioactive waste
What is fusion
When two atomic nuclei join to make a large nucleus
What conditions do you need for fusion
Lots of heat and pressure (from sun)
What happens in fusion
Nuclei with the same charge struggle to fuses as they repel
Heat and pressure from the sun fuses them together
Why is fusion safer
They leave few radioactive products when worn out
They don’t become dangerous if anything fails
