P4 - What is Radioactivity?

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What is a radioactive substance?
A substance that decays naturally by giving out alpha, beta and gamma radiation.
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What does nuclear radiation cause?
Ionisation by removing electrons from atoms or causing them to gain electrons
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What type of process is radioactive decay?
A random process; it isn't possible to predict exactly when a nucleus will decay
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What type of nuclei does radioisotopes have?
Unstable nuclei. Their nuclear particles aren't held together strongly enough.
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What is the half life of a radioisotope?
The average time for half the nuclei present to decay. It cannot be changed
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What is a nucleon?
A particle found in the nucleus. So protons and neutrons are nucleons.
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What happens to the nucleus when an alpha or beta particle is emitted from it?
The nucleus is a different element
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What are alpha particles good at?
Ionising because they are the largest particles emitted in radioactive decay which means they are more liekly to strike atoms of the material they are passing through, ionising them
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What are the properties of an alpha particle?
Positively charged, has a large mass, is a helium nucleus, has helium gas around it, consists of 2 protons and 2 neutrons
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What are the properties of a beta particle?
Negatively charged, has a very small mass, travels very fast, is an electron
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What happens to alpha particles during decay?
Mass number decreases by 4, nucleus has 2 fewer neutrons and 2 fewer protons, atomic number decreases by 2
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What happens to beta particles during decay?
Mass number is unchanged, nucleus has one less neutron, nucleus has one more proton, atomic number increases by one
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What is the nuclear equation for decay for alpha particles?
238,92 U -> 234,90 Th + 4,2 He
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What is the nuclear equation for decay for beta particles?
14,6 C -> 14,7 N + 0,-1e
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Other cards in this set

Card 2

Front

What does nuclear radiation cause?

Back

Ionisation by removing electrons from atoms or causing them to gain electrons

Card 3

Front

What type of process is radioactive decay?

Back

Preview of the front of card 3

Card 4

Front

What type of nuclei does radioisotopes have?

Back

Preview of the front of card 4

Card 5

Front

What is the half life of a radioisotope?

Back

Preview of the front of card 5
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