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History of Atomic Theory Timeline
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John Dalton
Resource2Resource1John Dalton had the foundation theory of atomic theory composition. He pioneered the atomic theory in 1803 and through his research he set these laws. They are: Pure Elements consisted of tiny particles called atoms. Atoms in an element are all the the same in that element. All atoms that make the element have the same mass. Atoms in elements can combined to form chemical compounds and atoms can neither be created or destroyed. -
Marie Curie
Mme. Curie was born on the 7th of November in 1867. She was the first person to win 2 noble prizes in history, for both physics and chemistry. With the help of her husband Pierre Curie, and the discovery of radioactivity by Henri Becquerel, The Curies further developed this idea and investigated the element uranium. In 1898 they discovered the element polonium, and radium. After the death of her husband in 1906, she took his place as Professor of General Physics in the Faculty of Sciences. -
Niels Bohr
Niels Bohr helped to shape the way in which we understand the atomic structure. Born on the 7th of October 1885. In 1912, Bohr was working with fellow scientist, J.J Thompson, and was introduced to Ernest Rutherford, who had recently discovered the particle nucleus. With the help of Rutherford, Bohr was able to understand the structure of the atom, and put forward a way to represent this. In 1922 Bohr was awarded a noble prize for this work. The model that Bohr proposed a neutral charge -
Erwin Schrodinger
Schrodinger’s greatest achievement was his contributions to the understanding of particle behavior. Schrodinger was not only involved in the field of physics, but languages and poetry. He achieved the a Habilitaion, the highest academic degree in 1914. During the 1890’s he experiment with light and color. It was in 1920 that, Schrodinger wrote 4 papers in which lie his most important scientific work, he also proposed “The Schrodinger Equation. -
James Chadwick
Chadwick was born on the 20th of October in 1891. He was mistakenly entered into the field of physics at Victoria University, Manchester. In 1913 he was awarded a masters and the exhibition scholarship in 1851. Chadwick is famous for his discovery of the neutron with the help of Ernest Rutherford, and was awarded a noble prize in 1935 for it. He was the head of the Manhattan project, and was present at the first atomic bomb test in Mexico. In 1945 we was knighted. -
Joseph John Thomson
In 1897, Joseph John Thomson discovered the electron whilst experimenting the nature of electric discharge in a high vacuum. He found that electrons ( negative charged particle )was the reason why cathode rays composed. His assistance was Francis Aston, who he assisted the discovery of isotopes. He also discovered the natural radioactivity of potassium and demonstrated that hydrogen had only a single electron per atom. -
Francis Aston
Resource2Resource1In 1901, Francis William Aston published his work of discovery on isotopes. He worked as the assistance of Sir J.J.Thomson at the Cavendish Laboratory. It was then before he worked for the war that he found evidence for the existence in isotopes. He then came back to complete the problem by inventing the Mass Spectrograph which had incredible focusing that allowed him to see the differences of the isotopes. By this study he also figured out the Whole Number Rule. -
Ernest Rutherford
Resource2Resource1In 1911, Ernest Rutherford discovered Alpha and Beta Rays and he made the law of Radioactive Decay. He established the theory of the nuclear atom. He found out that a positive nucleus in an atom was surrounded by negative electrons. He did this through an experiment looking at the particles that passed through foil, approximately 1 in 8000 we deflected. He found that most of the mass of the atom was in the nucleus hence the rest was empty space. -
Henry Mosely
Resource2Resource1In 1913, Henry Mosley discovered from x-rays of dozens of elements in the periodic table that the wavelength of the x-rays became shorter as the atomic weight increased, that this happened because of the positive charge also known as ‘proton’ in the nucleus. He sorted out the chemical elements of the periodic table in logical order. Because of his discovery, elements are now rearranged by atomic numbers without one element out of order. -
Murray Gell-Mann
Murray Gell-Mann is an American physicist, who was born in 1929, in New York. He entered university at the age of 15, obtained at degree in physics and a Ph.D. In 1952 Gell-Mann presented the concept of “strangeness.” A quantum property and the force that keeps the nucleus together. In 1961, working with another fellow physicist. Gell-Mann created a classification scheme based on interacting particles and arrangement of families, at this time, he also discovered the “quark.”
