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450
Democitus (465 B.C)
Democritus adopted the atomic theory from his mentor Leucippus, which stated "the universe is composed of two elements: the atoms and the void in which they exxist and move." Democritus thought that atoms can't be destoyed, they differ in size, shape and temp., are always moving, and can't be seen. he also believed that there is a great amount of atoms.
"A Brief History of Modern Atomic Theory." Chemistry Tutorial : History of Atomic Theory. N.p., n.d. Web. 25 Feb. 2014. <http://www.ausetute -
450
Aristotle (335 B.C)
Aristotle did not believe in the atoic theory at all so he taught others differntly. he thought all things on the earth were made of earth fire, water, and air, and earth was the center of the universe.
"Aristotle." The-History-of-the-Atom-.N.p., n.d. Web. 04 Mar.2014. -
Dalton A.D
version of atomic theory said that everything is made up of small and indestuctible particles that are alike with same atomic mass. Atoms from same element are alike but different from other elements. Used the Law of Mass Conservation, Law of Constant Composition, Law of Multiple Proportions and performed experiments with chemicals that showed matter was made of lumpy particals.
"A Brief History of Modern Atomic Theory." Chemistry Tutorial : History of Atomic Theory. N.p., n.d. Web. 05 Mar.2014 -
Thomson A.D
Stated that atoms consist of a large sphere of uniform posituve charge,have small negative charges,
He experiented with cathode ray tubes that showed that (positive charge) were different when different gases were used. (negative charge) were always identical regardlss of the nature of the elctrodes or gas used.
"A Brief History of Modern Atomic Theory." Chemistry Tutorial : History of Atomic Theory. N.p., n.d. Web. 25 Feb. 2014. http://www.ausetute.com.au/atomichist.html. -
Rutherford A.D
a small +charge is most of the atom in the nucleus, large volume around nucleus,+ charged nucleus, same # of protons & electrons. gold foil experiment using +charged alpha particles.the nucleus takes up 1billionth of the volume of atom "A Brief History of Modern Atomic Theory." Chemistry Tutorial : History of Atomic Theory. N.p., n.d. Web. 05 Mar. 2014. "HISTORY OF THE ATOM FROM DEMOCRITUS TO BOHR AND SCHRÖDINGER." HISTORY OF THE ATOM FROM DEMOCRITUS TO BOHR AND SCHRÖDINGER. N.p., n.d. Web. 0 -
Bohr A.D
Neils Bohr proposed that electrons orbit the nucleus without losing energy could only move in fixed orbits throughout the nucleus electrons with low energy orbit closer to the nucleus while the high energy electrons orbit further away.
He made the observation of a plantary diagram of the electrons orbiting around the nucleus like the planets. "HISTORY OF THE ATOM FROM DEMOCRITUS TO BOHR AND SCHRÖDINGER." HISTORY OF THE ATOM FROM DEMOCRITUS TO BOHR AND SCHRÖDINGER. N.p., n.d. Web. 05 Mar. 2014. -
Heisenberg and Schrodinger A.D
They made a wave equaiton that describes the form of the probablity waves the govern the motion of small particles and how these waves are altered by external influences
"Chemistry Project : The History Of The Atom." Chemistry Project : The History Of The Atom. N.p., n.d. Web. 06 Mar. 2014"Atomic Models." Atomic Models. N.p., n.d. Web. 06 Mar. 2014.
