-
400
Democritus create the first atomic theory
He was a Greek philosopher that was an infulence on the atomic theory. He devised that there was was an invisable partical that can not be cut into anything, It is what makes up all things. -
Jhon Dalton
He made the acusation that all things are made up of Atoms. He also published a three- part atomic theory.
1. All particles are made of atoms, they cant be destroyed.
2.Atoms of the same elements are identical
3. Atoms join with other substances to create new and different substances.
This was a -
John Dalton
He told everyone that the atomic theory, with spherical solid masses in motion. Atoms can't be made or destroyed. -
1869 Dmitri Mendeleev created the periodic table.
in 1869 Dmitri mendeleev created the periodic table -
JJ Thomson
He described atoms as ball of postive charge containing a number of electron, discovered the electron. -
J.J. Thomas discovers eletron
J.J. Thompson
Discovered electron
1897 – Cathode Ray
Experiment -
Ernest Rutherford Nucleus Theory 1910
Ernest Rutherford discovered the Nucleus Theory 1910 -
Discovery Of an Isatope
Discovered the existence of isotopes useing a mass spectrograph -
The Exsistance of an nutron
Chadwick proved the existance of neutron. He discoverd a particle within the nucleus that has a mass similar to a proton. -
The Nuclear fission was discover by lse meitner, Hahn, Strassman
1938 Lise Meitner, Hahn, Strassman discovered nuclear fission. -
Current Day Theroy
The current day model of an atom is based on a theory of quantum mechanics. Each electron is thought of as a cloud, of negative charge, instead of one tiny negative particle. An atom consists of energy levels, neutrons, and protons.
