Radioactivity

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  • Created by: Sam
  • Created on: 31-03-13 14:09
What is a radioactive material?
A radioactive material is a material that gives out nuclear radiation from the nucleus of each of its atoms.
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What happens to these nuclear atoms?
The atoms are unstable and decay naturally.
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What happens during this decay?
Radiation can be given out in the form of alpha, beta and gamma rays.
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What is an alpha particle?
An alpha particle is a helium nucleus.
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What is a beta particle?
A beta particle is a fast moving electron.
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What is gamma?
Gamma is energy in the form of an electromagnetic wave.
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How do you measure radiation?
By the number of decays emitted per second. (However, the number decrease through time)
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When does ionisation occur?
When an unchanged (neutral) atom gains or loses electrons.
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Which type of radiation is high inonising and why?
Alpha radiation is highly ionising. This is because it is missing two electrons, making have a -2 charge. It attracts electrons from atoms it passes, leaving them positively charged.
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What happens during an alpha emission?
The atom decays by rejecting an alpha particle from the nucleus.
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(In a alpha emission) list four ways in which the nucleus of a new atoms is different from the original one?
1) It is a different element. 2) It has two fewer protons and two fewer electrons. 3) The atomic number has decreased by two. 4) The mass number has decreased by four.
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What happens during a beta emission?
The atom decays by changing a neutron into a proton and an electron.
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What happens to the (high energy) electron?
The high energy electron, which is ejected from the nucleus, becomes a beta particle
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(In a beta emission) list three ways in which the nucleus of the new atom differs from the original one?
1) It has one more proton and one less neutron. 2) The atomic number has increased by one. 3)The mass number remains the same.
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What is a half-life?
A half-life is the time it takes for half the undecayed nuclei in a radioactive substance to decay.
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What happens if the substance has a very long half-life?
If a substance has a very long half life then it remains radioactive for a very long time.
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What do igneous rocks contain?
Igneous rocks contain uranium atoms which decay to produce stable atoms of lead.
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List two ways in which you can date rocks?
1) By measuring the proportion of uranium and lead in the rock. 2) Knowing the half-life of uranium.
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Other cards in this set

Card 2

Front

What happens to these nuclear atoms?

Back

The atoms are unstable and decay naturally.

Card 3

Front

What happens during this decay?

Back

Preview of the front of card 3

Card 4

Front

What is an alpha particle?

Back

Preview of the front of card 4

Card 5

Front

What is a beta particle?

Back

Preview of the front of card 5
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