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Democritus
Democritus is a Greek Philosopher whom questioned the atoms are found all around in the atmosphere, in all their states if of matter. He has questioned the idea that; if you break a piece of mater in half, and keep on doing so, the point which is than no longer capable of being broken. He referred to this as the basic matter of the particle the atom. This theory was than dismiessed by Arestole. -
Anotive Lavioiser
Antoine Lavoisier, a French nobleman, is known for being the father of modern chemistry. He had conducted many experiments which have led him to theories and conclusions which are still of practice today. He discovered that water is made from hydrogen and oxygen. He also came up with the idea of an analytical balance that highlighted the fact that chemical elements were neither created nor destroyed, but simply combine in different forms to create chemical reactions. -
John Dalton
John Dalton, an English Chemist, came up with a theory that proposed several ideas:1) All matter is made of atoms. Atoms are indivisible and indestructible.2) All atoms of a given element are identical in mass and properties3) Compounds are formed by a combination of two or more different kinds of atoms.4) A chemical reaction is a rearrangement of atoms.His theory has been adjusted in order to still be applicable to the atom after the all the evolution that it has gone through. -
D. Mendeleev
Mendeleev was the creator of the Periodic Table. It was created in order to find out important information various elements. The Periodic Table places all known elements in an order according on to their similarities. All atoms are also arranged based on their atomic number, the number of protons per atom. -
Joseph Thosemon
J.J. Thomson, a British physicist, was able to discover the electron in an atom through a series of experiments he conducted specifically charged to study the nature of electric discharged found in objects. He was able to calculate and provide evidence for a charge-to-mass ratio. He than later on suggested that the atom was a sphere of positive matter in which electrons where held in place by an electrostatic force. -
The Curies
The Curies were fasinated by the rtopic of radioactivity. they were able to show with the use of radioactivity that the atom was divisible. This had provin its significance becouse it providded eviidence that the atoms were indeed are visible, thus disproving daltons theory, -
Otto Hahn
The Canadian Physicist, Otto Hahn, was conducting a research on the element of uranium. Open researching, he discovered that when uranium is over crowded by its neutrons (its isotopes) it creates a smaller nuclei half the size of the initial nucleus. This allowed researches to understand that there is still a lot more to discover about the elements. -
Richard Abegg
The German Chemists, richard abegg had come to the conclusion that gasses must have a somewhat of a stable electronic configuration. The gas atoms wouldn’t add or subtract from their numbers, thus the reason they did not participate in chemical reactions. He assumed that this was because the atoms mat have given up or can no longer accept electrons. -
Robert Millikan
Robert Millikan, an American Chemist, was able to determine the unit charge on an electron using his oil-drop apparatus. He calculated the charge of electrons to be 1.60 x 10-19 coulombs. By finding the charge of the electrons their mass was than easier to equate for. -
Niels Bohr
Niels Bohr, a Danish Scientist, focused his research on the structure of the atom. His theory was combined with Rutherford’s ideas about the atom as well as with Planck’s Quantum Theory. Bohr suggested that the outermost layer of an atom includes more electrons than the charge that is found in the center of the atom. Bohr also played a big role in the description of the periodic table. -
Henry Mosely
Henry Mosely, A British chemist, whom had a big role to play in the editing of the previously existing period table. With the discover of the isotopes of elements, it became clear that the atomic weight of an atom does not play as big as a role as anticipates earlier but rather atoms where to be arranged by the atomic numbers. With this adjustment, Mosely was able to eliminate many of the problems that had appeared in the beginning. -
James Chadwick
A British Chemist, James Chadwick, focused on the study of radioactivity. Chadwick was able to discover the proton; a positively charged particle with the atoms center (nucleus). The nucleus is still known for including both protons and neutrons. -
Ernst Rutherforud
Ernest Rutherfors, was born and raised in New Zealand. He as responsible for the remaking of series of the radio active waves found as well as. His theory also suggested that all the mass in an atom is located in the middle of the atom itself. He was also able to discover two types of rays alpha and beta rays. -
Francis Aston
Francis Aston, a British Chemist who invented the “mass spectrograph”. He was the first person to take notice of isotopes. He observed the fact that their are three different kinds of hydrogen atoms. Modern atomic masses have a great influence from the the mass spectral analysis.
