-
460
Democritus
He created a theory that all matter was formed from tiny particles. Also, that the particles determined the properties of matter. He believed in the ultimate particle which was called the atom. -
Antoine Lavoisier
He created the Combustion Theory. This theory was based on mass measurements. Atoms could neither be made or destroyed. He also, named oxygen. He also proposed the Law of Conservation of Mass which is involved in basic chemistry these days. He is also known as "Father of Modern Chemistry". -
Joseph Louis Proust
He created the Law of Defintite Proportions. He also developed the use of hydrogen sulfide as a reagant. HIs measurements were very precise. This is because he measured in percentage weights, It was also very radical. -
John Dalton
HIs theoy was very simple. All matter is made of atoms. Atoms are indestructible and invisible. A chemical reaction is a rearrangment of atoms. Also, all atoms of an element are the same in mass and properties. -
MIchael Faraday
He made a very significant discovery. He discovered that electrical forces were the reason for atoms joining in a compound. He found this out by placing opposite electrodes in a solution of water which had a dissolved compound in it. -
Max Planck
He used 'quanta' to explain the hot glowin matter. With this knowledge, he gathered that energy is radiated in very small and simple amounts, unlike waves. He orginally proposde the quantum theory. After his discovery, Einstein followed and used his information. -
Henri Becquerel
He often observed x-rays and this is how he found something. He led to a more modern discovery of radiation. -
JJ Thomson
He proposed the 'plum pudding' model. This model consisted of the idea of electrons that he discovered. He believed a sphere was filled with postive and negative charges. He also thought that all matter was created by particles smaller than atoms. -
Robert Milikan
This man performed an experiment. This is widely known as MIlikan's oil experiment. During this experiment, the electrons charge was found. By using a microscope, perfume and oil, he was able to find out the charge of an electron. He continued Thomson's research. -
Ernest Rutherford
He created the gold foil experiment. He believed that all of the positive charge was in the middle with the nucleaus. He also believed that it was all held together by the eletrons holding it in place. -
Marie and Pierre Curie
They are best known for their work in the stuy of radioactivity. They discovered radium and polonium. She discovered radioactivity and was awarded. -
Niels Bohr
He worked off of Rutherford's idea. He believed that the electrons were in an orbit. He found that each was only able to contain a certain amount of electrons. HIs model was very successful! -
Albert Einstein (mid 1920s)
He created the quantum theory. Quantum theory is theory of matter and energy based on quanta, especially quantum mechanics. Also, is created to explain the radiation of energy. -
Louis DeBroglie
His theory was revolved around the wave mechanics theory. He believed that electrons could acts like waves and particles (like light). With this idea, it helped the atomic theory get so much more information. -
Erwin Schrodinger
He took the Bohr model one step further. He believed that electrons are in a circular orbits around the nucleaus. His model is the electron cloud model. -
James Chadwick
He discovered the neutron. He believed it consisted of both a proton and electron. -
Otto Hahn
He discovered the splitting of atoms. He discovered that barium could be produced when uranium was split. This could only happen when uranium had too neutrons thrown at it. -
Lise Meitner
She worked with Hahn for thrity years. She discovered the radiatonless transition known as the Auger effect. Hahn made it seem like she did not contribute to their studies. In her honor, she was given element 109 which was named meitnerium (Mt). -
Glen T. Seaborg
He discovered ten elements. He received a Nobel Prize in Chemistry for his hard work. He is best known for the element plutonium. -
Aristotle
He did not believe in the atomic theory. He believed that all matter was made of air, fire, water and earth. He said that no matter how many times matter was cut, there would always be a smaller form of that matter.
