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Democritis' Atomic Theory
-Atoms make up everything
-Atoms are indivisible and indestructable
-No scientific process
-Challenged by many other Greek philosophers -
Dalton's Atomic Theory
-Published 1802
-All elements are composed of atoms
-All atoms of the same element are alike and differ from all other atoms
-Atoms can chemically combine or mix together into new compounds
-When atoms join, seperate, or rearrange, a chemical reaction is caused
-An atom cannot become anything else -
Dalton's Model
Dalton believed that atoms were tiny, solid spheres with no smaller parts. -
Thomson's Model
Thomson believed that there must be electrons scattered randomly on the surface of a tiny, solid sphere. -
Marie Curie
-Discovered and named radioactivity
-Used mostly radium
-Died of aplastic anemia, a bone condition caused by overexposure to radiation. The effects of radiation were not known at the time
-First woman to be recognized by the Nobel Prize of Chemisty, and also the first person to recieve two Nobel Prizes -
Nagaoka's Model
Nagaoka believed that an atom has a central nucleus. -
JJ Thompson's Electron Theory
-Formulated and proved the concept of electrons
-Proved electrons to be a fundamental particle within atoms -
Milikan's Oil Drop Experiment
-Used oil to prove the 'elementary electric charge,' the electric charge of an electron -
Rutherford's Atomic Model
-Used gold foil to prove that atoms are mostly empty space with a dense nucleus (model known as the Nuclear Atom)
-Neutrons are distributed within the nucleus
-Electrons revolve around the nucleus and fill the majority of the volume of the atom -
Rutherford's Model
Rutherford believed that the nucleus of an atom must be dense and positively charged. He also believed that electrons orbit this central nucleus. -
Bohr's Model
Bohr believed that electrons orbit the nucleus at fixed distances. -
de Broglie's Proposal
de Broglie believed that electrons (and some other particles) had similar properties of waves. -
Schrodinger's Proposal
Schrodinger believed that electrons are in fixed positions around a nucleus, leading to the Electron Cloud model. -
Chadwick's Discovery
Chadwick proved that there are neutral neutrons in a nucleus.
