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12 Cards in this Set
- Front
- Back
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the periodic table is arranged in order of
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increasing atomic numbers
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the atomic number of an element is
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the same as the number of protons
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the number of electrons is the same as the number of protons in
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a neutral atom
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all atoms of an element have
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the same number of protons
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electrons
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have little mass and a negative (-) charge
they are located in election clouds or probability clouds outside the nucleus |
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protons
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have a positive (+) charge
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neutrons
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have no charge
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protons and neutrons are located
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in the nucleus of the atom and comprise most of its mass
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isotope
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an atom that has the same number of protons as the other atom of the same element but has a different number of neutrons
some are radioactive but many are not |
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half-life
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the length of time required for half of a given sample of a radioactive isotope to decay
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using a periodic table one can determine
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the atomic number
atomic mass number of protons number of electrons number of neutrons for any neutral atom of an element |
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formula for half-life if the initial radioactivity is x, the decay constant is k and t is the time
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x k^t = 1/2x
k^t = 1/2 t logk = log 1/2 t = - 0.301/logk |
