History of The Atom

Aristotle BC

370

-he didn't belive in atomic theory
-he thought all materials were not made of atoms but made of the four elements

Democritus BC

460

-He asked: Could matter be divided into smaller and smaller pieces forever, or was there a limit to the number of times a piece of matter could be divided?arious logical arguments
-used various logical arguments
-observations of the universe
-every day exsperiences

Dalton

Feb 28, 1803

-first to say all matter is made of atoms
-created "Dalton's Law"
-all atoms of the same element are identical
-chemical reations occur when atoms are rearranged
-compounds are formed from atoms of he consistant elements

Thomson

Feb 28, 1897

--studied "caral rays" and they were associated with the proton H+
-determined the charge to mass ration of an election= 1.759 x 108

Rutherford

Mar 6, 1909

-studied raditations
-used alpha particles
-electrons wer located outside nucleus
-discovery of nucleus (dense small positive charge)
-gold foil expierement

Bohr AD

Mar 6, 1922

-his theory was based on rutherfords
-thought atom was a small, positivly charged
-The element Bohrium is named after him
-used the Quanttum theory

Heinsenberg and Schrodinger

Mar 6, 1940

Heinsenberg:
-dealt with subatomic particles
-formed his theory by studying ligth given off by atoms
-described atoms by means of formula
-studied the spectra given off by atoms Schrodinger:
-exspanded Albert's theory of grantation to include electrical and magnetical phenonemon
-introduced "wave mechanics"
-developed the equation "Schrodinger equation"