Radioactivity

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Where does radiation come from?
Radioactivity comes from unstable radioactive isoptopes undergoing nuclear decay and spitting out high energy particles or waves.
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Why is radioactivity a random process?
Unstable nuclei give out ionising radiation. This process is random, so you can't say when any of the nuclei will decay and you can't make it happen either.
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What happens when a nucleus decays?
A decaying nucleus spits out one of more of three types of radiation - alpha, beta or gamma. In this process, the nucleus will change into a new element.
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What is ionisation?
Atoms lose or gain electrons to form ions. This is ionisation. Alpha, beta and gamma are all types of ionising radiation - they cause ionisation.
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Describe alpha particles.
They have a large positive charge. When an alpha particles passes close to an atom, it can pull a negatively charged electron out of orbit. They are strongly ionising as they are slow moving and they have a big mass/charge, but not very penetrative.
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Describe beta particles.
They have a negative charge and they push electrons out of orbit (like charges repel). They are electrons that are fast and small and are moderately ionising and penetrating.
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Describe gamma rays.
These can interact with the electrons orbiting an atom and transfer energy to them. If the electron gets enough energy, it can break free from the atom. They are weakly ionising but penetrate far. They are a type of EM radiation.
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What blocks the three types of radiation?
Alpha particles are blocked by paper/cardboard. Beta are blocked by thin aluminium. Gamma are blocked by thick lead.
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Other cards in this set

Card 2

Front

Why is radioactivity a random process?

Back

Unstable nuclei give out ionising radiation. This process is random, so you can't say when any of the nuclei will decay and you can't make it happen either.

Card 3

Front

What happens when a nucleus decays?

Back

Preview of the front of card 3

Card 4

Front

What is ionisation?

Back

Preview of the front of card 4

Card 5

Front

Describe alpha particles.

Back

Preview of the front of card 5
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