History of the Atom-David Clavijo

Democritus

400

Democritus, he believed the atom was unbreakable, if is wasn't for Democritus's atom discovery we would be nowhere near where we are today

Aristotle

400

Aristotles major contribution stated that atoms substances are made up of 4 elements. One was Earth, the second was fire, the third was water, and the fouth was air.

John Dalton

Mar 17, 1800

John Dalton, his atomic theory was that all mater is made up of tiny indivisible particles called atoms. The atoms of the same element are exactly alike thoseof different elements are different and have different masses, he transformed Democritus;s idea into a scientific theory

J.J thompson

Feb 27, 1897

Hos major contribution was discovering the electron, he conducted the cathode rays experiment. In his plum pudding model it displays electrons surounded in a sphere of negatively charged material.

Robert Millikan

Feb 25, 1909

Robert determined the mass and size charge of the electron, he also conducted his work by measuring the effect of an electric field on very small oil droplets. Lastly he was a noble prize winning physicist.

Ernest Rutherford

May 25, 1912

Rutherford discovered the nucleas. The atom contains a positivelty charged piece at the center. What made rutherfoed conclude? Well not all of the alpha particles passed through, and that's enough for Rutherford to conclude the plum pudding model was incorrect.

Neils bohr

Jan 27, 1913

Neils's major contribution proposed that an electron found only in specific circular paths, or certain orbits around the nucleas. Neilas's model reffered to as certain orbits because electrons move around the nucleas like planets around the sun.

Sir James Chadwick

Oct 27, 1932

James's Major Contribution confirmed the existence of the neutron in the nucleus. He was awarded the Nobel Prize for physics in 1935.

Neils Bohr

Jan 26, 2016