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Democritus Atomic Philosophy 492BC
A Greek philosopher who birthed the idea of atoms. He believed that atoms were indivisible and indestructible. His ideas worked with later scientifc theories but lacked experimental support and wasn't based off the scientific method. -
Period: 500 to Nov 6, 1000
Dark Ages of Science
A time in history where religion and politics over shadowed anything scientific and over all haulted the process of any new discovery. Also where medieval society slipped into barbarism. and ignorance. -
John Dalton- Dalton's model
English chemist, meteorologist and physicist.Nicknamed the "Father of Atomic Theory". Best known for his pioneering contributions in developing the modern atomic model.His model; claimed to be the fundamentals of physics and chemistry and was the first model to be backed up by scientific experiments. Although a genius of his time period he incorrectly stated that atoms are invisible and indestructible particles.
His hypothesis: elements combine at the atomic level in fixed ratios. -
Dalton Continued...
-Elements are made of incredibly small particles called atoms
-Atoms of equal element are equal in size, mass, and other properties. Atoms with different elements are different in size, mass, and other properties
-Atoms can't be subdivided, created, or destroyed-Atoms combine in whole number ratios to make compounds
-In chemical reactions atoms are combined, separated or rearranged -
Discovery of the Electron!
British physicist, JJ Thomson founder of electrons and isotopes and he also created the spectrometer.
Also awarded a Nobel prize for his discovery of the atom and his work of conduction and electricity & gases. -
Plum Pudding Model
J. J. Thomson proposed that the atom was negatively charged electrons floating in a possitively charged mass. -
Gold Foil Experiment
The gold foil experiment was made of a series of tests:positively charged alpha particles were shot at a very thin sheet of gold foil. If the Plum Pudding model was to be correct, the big alpha particles should have passed through the gold foil with only a few rejects. Because the alpha particles are heavy and the charge in the "plum pudding model" is widely spread. Many were reflected because they hit the nucleus. -
Rutherford's Model
Rutherford said that an atom was mostly empty space with a concentrated nucleus in the middle and electrons orbiting around it in unfixed orbits -
Electric Cloud Atomic Model
The current model of the atom is the electron cloud model. It was adopted in 1927. It takes into accound the Heisenberg uncertainty principle because it shows how you can never be sure where an electron will be. -
James Chadwick's Discovery
He discovered the existence of neutrons and that they had no charge at all. This meant that there was no electrical barrier to go through when trying to achieve atomic disintegration. This subsequently changed how the model of an atom would look like, and also allowed for atomic bombs to be made because of the presence of neutrons. -
Bohr
Niels Bohr took Rutherford's model to the next level by describing how electrons circled the nucleus in fixed paths called orbitals and how they could change orbitals with changes in energy, but could not orbit in between orbitals. He compared this to planets orbiting the sun. -
Uncertainty Principle
Werner Heisenberg, a German theoreticalphysicist, developed matrix mechanics to describe how you could never tell exactly where an electron was or how fast it was going.
