Unit 7 - Atomic Theory
[[Democritus[[
- Ancient Greek philosopher
- Atoms are uniform, solid, hard, and indestructible
- Move in infinite numbers until stopped
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[[John Dalton[[
- English chemist and physicist
- Proved all matter was composed of atoms
- Atoms cannot be subdivided, created, or destroyed
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[[William Crookes[[
- British chemist and physicist
- Created the Cathode Ray
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[[J.J. Thomson[[
- British physicist
- Found the electron using the Cathode Ray
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[[Robert Millikan[[
- Found the accurate mass of an electron
- Worked with J.J. Thomson
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[[Gold Foil Experiment[[
- Ernest Rutherford
- Alpha particles were shot at gold foil
- Found the nucleus and the proton
- Believed all particles would go through
- Most of the particles went through, however some bounced off at different angles
- An atom has lots of empty space
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[[James Chadwick[[
- English physicist
- Discovered the neutron
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| Electron | Proton | Neutron | |
|---|---|---|---|
| Symbol | e | p | n |
| Charge | 1- | 1+ | 0 |
| Actual Mass | 9.11 x 10^-28 | 1.673 x 10^-24 | 1.675 x 10^-24 |
| Location | Outside the nucleus | Nucleus | Nucleus |
| Discovery | Cathode Ray | Gold Foil Experiment | Beryllium Experiment |
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[[SAPs[[
- Number of protons make elements differ
- Number of protons = atomic number = electrons
- Mass Number: protons + neutrons
- Mass number - atomic number = neutrons
- Isotopes: different forms of the same atoms that very in mass
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[[Different Notations[[
- Hyphen Notation: Copper - 63 or Cu - 63 * 63 is the mass number
- Nuclear Symbol: 63/29 Cu * 63 is mass number and 29 atomic number
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[[Henri Becquerel[[
- French scientist
- Accidentally discovered radiation
- Radioactivity: spontaneous emission of radiation caused by the decay of an unstable atomic nuclei
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