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Democritus 440 BCE
Democritus was a Greek philosopher who identified and named the atom. He thought that once you cut something in half again and again you would eventually end up with a particle that could not be cut. He called this particle an atom. The word atom is from the Greek word atomos which means "not able to be divided." -
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Aristotle 382 BCA
He was a Greek philosopher, who believed that Democritus's ideas weren't right. He thought that you could never end up with an atom you couldn't cut in half, which Democritus's said you could. -
Dalton
He questioned why elements combine in certain proportions based on mass to form compounds. He figured out that elements combine in certain proportions because they are made of single atoms. He stated the following ideas in his theory. -
Thomson
Thomson proved that there was a problem in Dalton's theory. Thomson figured out that there are tiny particles inside an atom. This proves that atoms can be cut into even smaller parts. He experimented with a cathode-ray tube. -
Rutherford
He decided to test Thomson's theory, so he created a way to study the parts of an atom. He also discovered that atoms are not always soft "blobs" that sometimes there hard. -
Rutherford
He revised the atomic theory and created a new model of an atom. He identified the nucleus and found out the diameter is 100,000 times smaller than the diameter of the gold atom. -
Bohr
He studied who atoms react with light and realized that electrons move around the nucleus in certain paths, or energy levels. In his model there are no paths between the levels. Electrons though can jump into another path and into another level. -
Schrodinger and Heisenberg
They are 2 scientists that further described the electrons in an atom. As Bohr said electrons don't travel in a definite path. Schrodinger and Heisenberg proved that electrons path cannot even be predicted.
