-
350
Aristotle
Disagreed with most scientists, and believed that atoms didn't exist. He believed everything was made up of combinations of earth, water, air, and fire. -
400
Democritus
First model of the atom; a ball. Unlike Aristotle, he knew atoms existed. -
Antoine Lavoisier
Started conversation on what the atom was, and can be associated with the creation of the law of conservation of mass. -
John Dalton
Created atomic theory of matter, which included fidings from Democritus. All matter is made of atoms that when combined with different elements created compounds. -
Henri Becquerel
He made many discoveries in the field of radioactivity that would lead to the perfection of the atomic model in later years. -
J.J. Thomson
Discovery of electron lead to the ball model to becoming a "plum pudding" model. -
Marie & Pierre Curie
Expanded on Becquerel's work on radioactivity to create the dot diagram model, which showed the electrons. -
Max Planck
Creation of quantum theory would lead to use of energy in the atomic model. -
Robert Millikan
Inspired by J.J. Thomson's finding of the electron, he proved that the electron is much smaller than the rest of the atom -
Ernest Rutherford
Feeling the need to improve J.J. Thomson's model, he created a model that had a posotive nucleas with electrons surrounding it. -
Niels Bohr
Bohr created a new model based off of his teacher Rutherford's model. The new model contained energy levels. He used Planck's ideas to creare quantum mechanics. -
Henry Mosely
Worked with Bohr to find out that atomic number correlated with number of protons. -
Erwin Schrodinger
Changed quantum mechanical model of the atom by calculating probability of an electron being a certain distance from the nucleas. -
Werner Heisenberg
A scientist who shares his name with TV's favorite drug lord proposed that the exact distance of an electron from the rest of the nucleas wasn't exact. -
James Chadwick
Curious about a difference in mass and number of protons, James Chadwick discovers the neutron.
