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Democritus
• Atomic theory:
• atoms were specific to the material which they composed
• everything is composed of "atoms”
• atoms are indestructible
• infinite number of atoms, and kinds of atoms, which differ in shape, and size
• Atoms are indivisible, firm, and completely solid
• remain unchanged, but move about in space to combine in various ways
Democritus is called "the father of science" because of his atomic theory. The atomic theory as we know it started with him. -
John Dalton
•atoms of different elements have different masses
•atoms of the same element are all exactly the same
*atoms cannot be created, destroyed, or split
•chemical reactions cause atoms to link together or separate
•atoms combine in simple whole number ratios to form compounds
Daltons major contributions were stating that all gases could become liquids at the right temperature and the pressure of gas in a container varies directly with the temperature. He was also well known for his work with atoms. -
JJ Thomson
Thomsons' concept on the atom was shown with his " plum pudding" model. Where the electrons are the plum and the positive "pudding" is inside.
Thomsons main contribution to science was his dicovery of the electrons. -
Robert Millikan
His concept of the atom was mostly the same as Thomson he only added the charge of electrons.
Major contribution was the oil drop experiment which measured the charge of electrons. -
Ernest Rutherford
discovered the nucleus
positive nucleus with many electrons orbiting it
planetary system model
dicovered that electrons orbit around the nucleus with his goldfoil experiment.
Rutherford shot altha particles through a thin sheet of gold and some light particles deflected off of it. This proved that an atom is actually a small dense nucleus surrounded by orbiting electrons. -
Niels Bohr
developed a new model in which electrons orbit around the nucleus on different levels or floors and can jump from to floor
models is known as the bohr model and bohrs idea caused contravirsy among his peers but were later excepted. -
Erwin Schrodinger
Atomic Theory:
*electons travel in their orbitals and are constantly moving
*all matter acts like waves including electrons
*main orbitals s, p, d, and f
*formed the cloud model
Well know for his work with the quantum theory and his work with wave mechanics (schrodinger equation). -
Werner Heisenberg
The only change he made to the atomic theory was he calculated the behavior of electrons and he said that surrounding the nucleus there is an elctron cloud.
Heisenbergs contribution to the atomic theory was he included quantum mechanics. -
James Chadwick
*proved the exisits of nuetrons.
Chadwicks effected atom model greatly because another subatomic particle was found in the atom.
