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1766-John Dalton
John Dalton was a British chemist and a schoolteacher. He wanted to know why elements combine into certsin proportions based on mass to form compounds. His results suggested that elemennts combine in certain proportions because they are made of single atoms. his theory stated that all substances are made up of atoms. It also states that all atoms of the same element ar exactly alike and atoms of diffret elements are different. Also atoms join with other atoms to make new substances. -
Rutherford 1909
A former thompson student named Ernest Rutherford decided to test Thompson's theory. he desighned a expierement to study the parts of an atom. he aimed a beam of small positivally charged particals at a thin sheet of gold foil. the coating glowed when hit the positivally charged particals. Rutherford then see where the particals went after hitting the gold. -
Thomson
thomson proposed that electrons weere located throughout an atom like plums in a pudding, as shown in this model. -
Rutherford
Ernest Rutherford publishes his atomic theory describing the atom as having a central positive nucleus surrounded by negative orbiting electrons. This model suggested that most of the mass of the atom was contained in the small nucleus, and that the rest of the atom was mostly empty space. Rutherford came to this conclusion following the results of his famous gold foil experiment. -
Bohr
Bohr model, introduced by Niels Bohr in 1913, depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus—similar in structure to the solar system, but with electrostatic forces providing attraction, rather than gravity. -
Schrodinger and Heisenberg
Schrodinger and Heisenberg are known to be two of the important founders of quantum mechanics. They both invented a mathematical formalism for quantum mechanics. Schrodinger's formalism which was based on the wave equation was the most popular one. Heisenberg's formalism was based on the notion of quantum jumps. -
460 bc -Democritus
A Greek philosopher named Democritus thought that you would eventually end up with a partical that could not be cut. He called this partical an atom. -
Aristotle
Aristotle’s theory made a great generalization off all matter being made of the four elements: fire, water, earth, and air. He also believed that there were four qualities to these elements: dryness, hotness, coldness, and moistness. Based on these beliefs fire would hold the characteristics of being dry and hot, water is wet and cold, air is hot and wet, while the earth is dry and cold.
