History of the Atom Timeline

Aristotle

350

Approx his discovery waws made in 350 B.C.Many of his ideas were more thought based then scientifically based. He made up the four elements..

Democritus

400

http://thelittleguy22.tripod.com/id1.html- He discovered that all atoms are solid, insdestructable, and unique.
- He theorized that these tiny particles some how had hooks attached to them so they could stick together.

Dalton

Feb 28, 1803

http://www.rsc.org/chemsoc/timeline/pages/1803.html Approx his discovery was made in 1803.Method-

• all matter is made of atoms all atoms of given element are identical in mass and properties. He had a model called "Billard Balls"

Thomson

Apr 30, 1871

• He discovered that atoms had electrons so he added electrons to the model of the atom.
• He used many methods.-Used a cathade ray tub filled with a gas that he charged.
• Famous method- plum padding model-He thought it was an atom with electrons randomly placed inside.

*these notes were found is a friend notes.

Bohr

Mar 13, 1913

http://www.chalkbored.com/lessons/chemistry-11/atomic-models-handout.pdfApprox his discovery was made in 1913 He added electrons to the atom model he had a famous model called the Bohr model

Rutherford

Mar 13, 2014

http://www.britannica.com/EBchecked/topic/514229/Ernest-Rutherford-Baron-Rutherford-of-NelsonHis discovery was in 1911. He added electrons to the model He had a model in common with someone else they did the same method it was called the Bohr method