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470
Democritus
Democritus was a Greek Philosipher that lived from 460 BC to 370 BC. There is no exact date of dis discovery. But he discoverd the basic idea of the atom. His contribution was the idea of the atom and is known as the start of modern science. His errors in the atoms is he thought that adoms coundn't break down anymore than they are. HE also belived there were infinate types of atoms. -
500
Greeks
The greeks had 2 main philosiphers that contrbuted to the atomic theory. They were Democritus and Aristotle. They both came up with the idea of the atom. But they thought that an atom was as simple as it could get. Which they were wrong about. -
John Dalton
John Dalton was an English chemist. Daltons theory is 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.
He was a big contribtuer because he figured a lot about the basic atom and helped us discover more about it later.
(thats all i can put) -
Max Planck
Max Planck was a German Scientist who heled with the atomictheroy. He came up with many diagrams and ideas over many years. He didn't know all the parts but had a very good idea and helped with the atomic theroy. -
JJ Thomson
JJ Tomson In 1897 the British physicist discoverd the electron. He discoved that it has a negitive charge as well. His shortcoming was he didnt know that there was a positvely charged nucleus as well. -
Ernest Ruthorford
Ernest Ruthorford was an New Zealand-born physicist. He discoverd the positive nucluas of the atom, which happend in 1911. This a major discovery because the positive charge of the nuclues was unknown before this. He dicoverd this with a beam of light. He didn't figure out everything but was still a big part of the atom -
Niels Bohr
Niels Bohr is a was a Danish physicist who made contributions to understanding atomic structure and quantum theory. Which happened in 1911. His shortcomings are he didn't figure out what all the electons and stuff do. -
Electron Cloud Model
The electron cloud model was dicoverd by 3 different scientists Ernest Rutherford, Niels Bohr, and Werner Heisenberg. it is an atomic orbital is a mathematical function that describes the wave-like behavior of either one electron or a pair of electrons in an atom. -
James Chadwick
James Chadwick is an English Phisicist who discoverd the neutron in 1932. His shortcomings are he assumed stuff about the nuetrons that wern't true. -
Albert Einstien
Albert Einstein contrbution to the atomic theory is he was actually able to prove it is real. By sing his theories in quantum physics to explain the photoelectric effect and Brownian motion. This didnt happen at any certain time just over a while
