positively charged nucleus surrounding by negatively charged electrons orbiting around the nucleus .
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what does the mass number tell us ?
the number of protons and neutrons
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what does the atomic number tells us ?
the number of protons
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what is an isotope ?
isotope have the same number of protons but different number of neutrons
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what is the activity of a radioactive isotope measured in ?
bq
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what do we use to measure count rate ?
geiger-muller tube
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what does ionisation mean?
an atom turns into ion ( charged particle) by losing or gaining an electron
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name the 4 type of radiation ?
alpha, gamma , beta and neutron
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what is an alpha particle made of and what is the symbol for it ?
2 protons and 2 neutrons
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what is the mass and charge of an alpha particle ?
mass=2
charge = +2
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what is a beta particle made of and what is the symbol for a beta particle ?
a high energy electrons
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what is the mass and charge of beta particle ?
mass = 0
charge = -1
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what is the plum pudding model ?
an early model of the atom where the atom is a ball of positive charge with negative electrons embedded in it .
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what was the experiment that disproved the plum pudding model?
the gold foil/alpha scattering experiment; alpha particles were fired at gold foil. plum pudding model predicated all would travel straight through; but some were deflected and reflected straight back.
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what was the nuclear model of the atom?
The model that was proposed after the plum pudding model , with atoms having a small positively charged nucleus surrounded by electrons.
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why was the nuclear model of the atom proposed ?
because the alpha scattering experiment produced evidence that could not be explained by the plum-pudding model.
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what happens to the mass number/atomic number during alpha decay ?
mass number goes down by 4
atomic number goes down by 2
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what happens to the mass number/atomic number during beta decay?
mass number - no charge.
atomic number goes up by 1
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what is irradiation used for ?
sterilising food/medical equipment .
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why is radiation dangerous ?
can mutate ,lead to cancer/ radiation sickness and even death
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what can we do to keep safe around radiation?
keep as far away as possible, spend as little time as possible near radioactive source, shield yourself with thick lead/concrete .
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Other cards in this set
Card 2
Front
describe the structure of an atom?
Back
positively charged nucleus surrounding by negatively charged electrons orbiting around the nucleus .
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