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370 BCE
Atoms first theory
Democritus was a greek philosopher wasnt a firm believer in his fellow philosophers saying the universe was made of earth fire, water, and air. He belived that the universe was made of atoms and the void it fills. He was the first person to believe in this concept. -
John Dalton Theory of Atomic Matter
In the year 1803 John Dalton wrot a theoty based on these Ideas
1) All atom are made of atoms and it is impossible to divide or destroy an atom
2) All atoms of the same element are alike.
3) Atoms of different elements are different
4) Atoms of different elements combine to form compounds and have to be a Definite Whole Number Ratio. -
Magical Electrons and when we found them
In 1897 a man named J.J Thompson was experimenting with gas discharge tubes and noticed movement that he called cathode rays. The cathode rays had moved from the negative end of the tube to the positive end of the tube making him realize they were negatively charged. That is when he discovered electrons -
The discover of the nucleus of an atom
In between the time of 1871 and 1937 a man named Ernest Rutherford conducted a famous experiment called the gold foil experiment. In the experiment he used special equipment to shoot alpha particals at a thin sheet of gold foil. In doing this he learned that. In doing so he found out in 1911that there was a small positivly charged nucleus and that most of the atoms are empty space. -
The first attempt at quantum theory
The first attempt at quantum theory was made by a Danish physicist Niels Bor in 1903. He did it to account for the structure of atoms.
