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12 Cards in this Set
- Front
- Back
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define radioactivity
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radioactivity is the spontaneous breaking up of unstable nucleii with the emission of one or more types of radiation
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what is the a) nature b) charge and c) penetration ability of an Alpha Particle
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a) 2 protons and 2 neutrons emitted from the nucleus (He)
b) positive (2+) c) stopped by paper or few cm of air |
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what is the a) nature b) charge and c) penetration ability of a Beta Particle
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a) neutron changes into a proton and electron. Electron is emitted from nucleus. Electron is Beta Particle
b) negative (1-) c) stopped by 5mm of aluminium |
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what is the a) nature b) charge and c) penetration ability of Gamma Radiation
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a) surplus of energy in the form of high energy electromagnetic radiation emitted from the nucleus
b) neutral c) stopped by several cm of lead. Energy eventually absorbed |
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give an example of
a) alpha particle b) beta particle c) gamma radiation |
a) americium-241
b) strontium-90 c) cobalt-60 |
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what's the difference between a chemical reaction and a nuclear reaction?
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a chemical reaction involves formation and breaking of bonds between atoms by sharing/donating electrons
a nuclear reaction is the change in the nucleus of atoms; it changes the atom into an atom of a completely new element. the changing of one element into another is called Transmutation |
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general equation for the emission of an alpha particle
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A A-4 4
X -------> (X-2) + He Z Z-2 2 |
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general equation for the emission of a beta particle
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A A
X ------> (X+1) +e- Z Z=1 |
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define half life
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the half-life of an element is the time taken for half of the nucleii in any given sample to decay
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how is half-life measured?
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using a geiger-muller tube and a ratemeter. The ratemeter counts the number of radioactive particles being emitted per second. This is graphed against the time taken for a source to decay.
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uses of radioisotopes
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Medical: radiotherapy and to sterilise medical instruments
Archaeological: Carbon-14 dating shows how old something is Food Irradiation: gamma rays kill micro-organisms Industrial: to investigate leaks, a radioisotope is added to the water and a GM tube is used |
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french scientist who discovered radiation?
two elements discovered by the Curies? |
Henri Becquerel
Polonium and Radium |
