History of the Atom

Democritus

430

Democritus was the first to wonder what will happen if you break a peice of matter. His idea was dismissed because a major scientist at the time, Aristotle, dismissed the idea. The idea was not revisited until the 1600's.

Dalton

Sep 30, 1800

The original idea of the atom wa seriously revisited by Dalton in the 1800's. His experiments led him to believe that all matter is made up of particles that can be large or small. These particles are known today as atoms.

Thomson

Sep 30, 1897

97 years after the atomic theory was revisited, JJ Thomson discovered a huge fact about the atom. Every atom contains electrons. With this discovery, he also found that there is a negative part of each atom. He created the Plum Pudding Model.

Rutherford

Sep 30, 1911

In 1911, Ruhterford tried bobarding atoms with alpha rays. He used radium for the rays and shined them onto atoms in tin foil. He reasoned that in the space where the rays didnt go, there were electrons. This was a major discovery in the history of the atom. His evidence suggested that the Plum Pudding Model was incorrect.

Bohr

Sep 30, 1912

Bohr, a Danish physicist, theorized that electrons do not spiral into the nucleus as thought. He had two major rules that he thought may be correct:
1. Electrons can only orbit at a certain distance from the nucleus.
2. Atoms radiate energy when electrons jump from higher energy orbits into lower energy orbits.

Schrodinger

Oct 1, 1926

Schrodinger was a well known scientist during his time. He created a very intricate model of the atom using equations and other mathmatic solutions.

Chadwick

Oct 1, 1932

In 1932, James Chadwick would make a discovery that would forever change the way scientists look at atoms. In 1932, Chadwick discovered the nuetron. In this year he was awarded the Nobel Peace prize in chemistry for his discovery.