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16 Cards in this Set
- Front
- Back
Democritos believed matter was made of extremely small particles that could not be divided called atoms. |
Ancient Greece |
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Did not think there was a limit to the number of ways matter could be divided. |
Aristotle |
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Thought all matter was made of individual particles called atoms that could not be divided. |
John Dalton |
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Provided the first evidence that atoms are made of smaller particles. |
J.J. Thompson |
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Passed alpha particles through a very thin gold foil. |
Ernest Rutherford |
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Electrons move in a less predictable was that Bohr thought. |
Electron Cloud Model |
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A visual model of the most likely locations for electrons in an atom. |
Electron Cloud |
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A region of space around the nucleus whee an electron is likely to be found. |
Orbital |
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Model of an atom include nucleus surrounded by electrons. |
Niels Bohrs |
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Possible energies that electrons in an atom can have. |
Energy level |
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smallest particle of an element. |
Atom |
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A positively charges subatomic particle that is found in the nucleus of an atom has charge of 1+. |
Electron |
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A neutral subatomic particle found in the nucleus of an atom. It's mass is almost exactly equal to a proton. |
Neutron |
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The number of protons in an atom of that element. |
Atomic number |
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The sum of the protons and neutrons of that atom. |
Mass number |
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Atoms of the same element with different numbers of neutrons and different mass numbers. |
Isotopes |