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101
Demoncritus. 429 BC
First peron to think of the atom
Thought atom was a solid sphere. -
101
Aristotles 400 BC
Thought atom was made up of the four elements:fire, air, earth, water -
Newton
Tiny pieces of mass "swimming everywhere" -
Dalton
-All matter = atoms(true)
-Atoms cannot be destoyed(false, nuclear reaction)
-Atoms of the same elemnet are identical(false, isotopes)
-Different elements = different atoms(true)
-Chemical recations can rearrange atoms(true)
-Compounds =atoms of different elements(true) -
Thomspon
Experiment: Cathode Ray Tube
Proved exsistence of negitively charged particles, later called electrons. (called the choclate chip cookie or plum pudding) -
Andrews
Experiement: Oil Drop
-measured charge of a single electron -
Rutherford
Experiment- Gold Foil
- atom has central positive nuclues surrounded by negative orbiting electrons -
Bohr
-Depicted atoms of small, positively charged nucleus surrounded by electrons.
-Electrons travel in circle motion(like solar system) -
Milikan
Identified 212 neutral isotopes of non-radioactive elements -
Aston
Discovered isotopes of non-radioactive elements -
Schrodinger
-Atoms consist of nucleus and clouds
-Formula calculated odds where electrons may be
-Bohr model wrong -
Chadwick
Discovered neutron