Zusammenfassung der Ressource
P5: Radioactive Materials
- Types of
Ionising
Radiation
- Alpha
- 2 neutrons, 2 protons.
Big, heavy, slow moving.
- Beta
- Identical to an electron, move quite fast and
are small. For every beta particle emitted, a
neutron turns into a proton in nucleus.
- Gamma
Rays
- Helps get rid of extra energy,
high frequency, no mass or
charge, just transfers energy.
- If nucleus contains lots of neutrons, it may
just throw it out. The nuclear mass
changes because of that, so it becomes a
different isotope of the same element.
- Balancing
Nuclear
Equations
- Emitting an
Alpha
Particle
- Mass decreases by 4 -
loses 2 protons and
neutrons, charge
decreases by 2.
- Emitting a
Beta Particle
- Mass doesn't change -
lost neutron but gained
proton, nuclear charge
increases by 1
- Emitting a
Gamma Ray
- Mass or charge
doesn't change
- Half-Life
- The average time taken
taken for its activity to
halve.
- Dangers of
Radioactivity
- Ionising
Radiation Harms
Living Cells
- Ionising Radiation enter living cells and interact
with molecules. Lower doses damage living cells by
causing mutations in the DNA, which causes the
cell to divide uncontrollably (cancer). Higher doses
kill cells completely, which causes radiation
sickness if a lot of cells get blasted at once.
- Hazards Depends on
the Type of
Radiation
- Beta and gamma are the most dangerous (outside the body), because
beta particles and gamma rays can penetrate the body and get to
delicate organs. Alpha particles are the least dangerous because they can't
penetrate the skin, easily blocked by a small air gap. Inside the body, alpha
particles are most dangerous, because they do all their damage in a
localised area. Beta and gamma rays are the least dangerous in the body.
- Uses of
Radiation
- Tracers in medicine -
Gamma
- Radiotherapy -
Treatment of cancer