Section 3- Radioactivity And Astronomy Flashcards
Relative mass of a proton
1
Relative mass of a neutron
1
Relative mass of an electron
0.0005
Relative charge of a proton
+1
Relative charge of a neutron
0
Relative charge of an electron
-1
What does it mean if an atom is ionised?
It has lost an electron
Isotopes
Isotopes of an element are atoms with the same number of protons but a different number of neutrons
Half-life
The half-life is the average time taken for the number of radioactive nuclei in an isotope to half
Nuclear fission
Nuclear fission is a type of nuclear reaction that is used to release energy from uranium atoms
Sources of background radiation
- in the air
- some foods
- rocks
- building materials
Uses of radiation
- fire alarms
- sterilising medical equipment
- fresh fruit
Dangers of radiation
- can enter living cells and ionise atoms and molecules within them. This can lead to tissue damage
- radiation sickness (leads to vomiting, tiredness and hair loss)
- cancer
Nuclear Fussion
Nuclear fusion is the opposite of nuclear fission. In nuclear fusion, two light nuclei collide at high speed and join (fuse) to create a larger heavier nucleus
Why does nuclear fusion only only occur at high temperatures?
This because the positively charged nuclei have to get very close to fuse so the strong force due to electrostatic repulsion has to be overcome (10 000 000 °c)
