REVIEWER (Active Recall)
Atoms – The smallest unit of matter.
Molecules - The smallest portion of a substance.
Leucippus and Democritus (5th century BCE)
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ATOMOS “indivisible”
John Dalton
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The Solid Sphere/Billiard Ball Model
The Modern Atomic Theory of Matter
- Matter is made up of small, invisible, and indivisible particles called atoms
- Atoms of the same element have the same properties
- Atoms cannot be created nor destroyed
- Atoms combine in whole number ratios to create compounds
Joseph John Thomson
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The Plum-Pudding/Raisin Bread Model
Discovered the electron using the Cathode Ray Tube experiment
Ernest Rutherford
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The Nuclear Model
Discovered the nucleus using the Gold Foil experiment
James Chadwick
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Discovered the neutron
Niels Bohr
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The Planetary Model
Erwin Schrodinger
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The Quantum Mechanical Model
Atomic Number (Z)
Atomic Mass (A)
Proton (p+)
Electron (e-)
Neutron (n0)