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19 Cards in this Set
- Front
- Back
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Thomson |
Electrons are imbedded in a positive sphere (plum pudding analogy) |
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Rutherford |
Atoms are mostly empty space with a positively charged nucleus (gold foil experiment) |
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Bohr |
Electrons are found in different energy levels |
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Democritus |
Tiny particles are called atoms (400 BC) |
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Dalton |
Atoms are a solid sphere (1800s) |
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Electrical Charge of protons |
Positve (1+) |
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Electrical charge of neutrons |
Neutral (0) |
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Electrical charge of electrons |
Negative (1-) |
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Gell-man |
Proposed the quark theory |
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Up quarks and down quarks |
Two elementary particles that make up atoms |
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1 atomic mass unit |
Unit of measurement for atomic particles |
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2 up 1 down |
Combination of quarks that make up a proton |
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Isotopes |
Atoms of the same element with different numbers of neutrons |
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Mass number |
Sum of the number of protons and neutrons in an atom |
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Dmitri mendeleev |
Devised the 1st periodic table based on the atomic mass |
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Henry mosely |
Arranged elements by atomic number rather than atomic mass |
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Super novas |
Spread heavier elements throughout the universe |
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Average atomic mass |
Weighted average mass of a mixture of its isotopes |
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Atomic number |
Number of protons in an atoms nucleus |
