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Atomic Theory
Scientist Facts
Question | Answer |
---|---|
440 B.C. | Democritus |
Atoms are uncuttable | Democritus |
"Atomos" meaning indivisible | Democritus |
1803 | Dalton |
Atoms of different elements are different | Dalton |
Conducted experiment combining elements; elements combine in proportions | Dalton |
All substances are made of atoms | Dalton |
Atoms of the same element are exactly alike | Dalton |
1897 | Thomson |
Small, negatively charged particles inside the atom | Thomson |
Cathode Ray Tube Experiment | Thomson |
Plum Pudding Model | Thomson |
1911 | Rutherford |
Small, dense positively charged nucleus | Rutherford |
Most of an atom's mass is in the nucleus | Rutherford |
Atoms contain mostly empty space | Rutherford |
Electrons travel around nucleus like planets | Rutherford |
Gold Foil Experiment | Rutherford |
1913 | Bohr |
Electrons jump between levels from path to path | Bohr |
Electrons travel in definite paths | Bohr |
Electron paths are called levels | Bohr |
Twentieth century | Heisenberg and Schrodinger |
Electrons are found in electron clouds not paths | Heisenberg and Schrodinger |
Electron paths cannot be predicted | Heisenberg and Schrodinger |
Atoms cannot be created, divided, or destroyed | Dalton |
Levels are certain distances from the nucleus | Bohr |
No paths are located between levels | Bohr |
Inside the nucleus is the protons | Heisenberg and Schrodinger |