Atomic Theory

Events

Democritus

Approx. 400 B.C.

He was the first person to study and experiment atoms. He gave the 1st atomic theory of 1: All matter consists of atoms 2: Atoms are indestructible 3: Atoms are solid but invisible 4: Atoms are homogenous 5: Atoms differ in size, shape, mass, position, and arrangement

Dalton

1803

He brought back up atomic theory after Democritus's theory wasn't believed. His theory was 1: All matter is made of atoms. Atoms are indivisible and indestructible 2: All atoms of a given element are identical in mass and properties 3: Compounds are formed by a combination of two or more different kinds of atoms 4: A chemical reaction is a rearrangement of atoms.

Milikan

1908

He did the oil drop experiment. This helped with understanding the charge of the electron and the structure of the atom.

Rutherford

1911

He did the gold foil experiment which showed that a atom had a nucleus.

Bohr

1913

He proposed that electrons orbit around the nucleus.

Schrodinger

1926

He developed the electron cloud theory.

Heisenberg

1927

He made the idea of quantum theory which was used for interpreting the behavior of particles and atoms.

Chadwick

1931

He bombarded beryllium atoms with alpha particles and seen a radiation was produced. This showed that there was a neutral charge and he concluded the neutron was about the same mass as a proton.

Work cited

2016

"Dalton's Atomic Theory." Dalton's Atomic Theory. N.p., n.d. Web. 23 Oct. 2016.
"Milikan Oil Drop Experiment." N.p., n.d. Web. 23 Oct. 2016.
"Rutherford Model." Wikipedia. Wikimedia Foundation, n.d. Web. 23 Oct. 2016.
"Development of the Atomic Theory." Development of the Atomic Theory. N.p., n.d. Web. 23 Oct. 2016.
"Atomic Theory." Atomic Theory. N.p., n.d. Web. 23 Oct. 2016
"Niels Bohr - Facts." Niels Bohr - Facts. N.p., n.d. Web. 23 Oct. 2016.

"Werner Heisenberg." The-History-of-the-Atom -. N.p., n.d. Web. 23 Oct. 2016
"Democritus of Abdera." - IGGY. N.p., n.d. Web. 23 Oct. 2016.