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100
Democritus
Democritus lived from 460 BC to 370 BC and was an ancient Greek philosopher.He was a pupil of Leucippus and an influential pre-Socratic philosopher who produced what is thought to be, the first atomic theory.According to Democritus, everything is made up of atoms. These atoms are physically, though not geometrically, invisible; between atoms lays free space. Atoms are indestructible and always will be. 'The Democritean’ is an inert solid that communicates with different atoms mechanically. -
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Thales
Thales was born in the mid 620’s BC and was Greek. He was a man who contributed much to the evolution of the atomic theory and also in chemistry, even though that the term ‘chemistry’ didn’t really exist in his time.Thales studied the science of geometry when he travelled to Egypt.He declared that the origin of all matter is water. Today, we know the largest constituent of the universe is hydrogen, which makes two of three atoms in water (H2O). The atom that was missing was added late -
100
Aristotle
Aristotle was born 384 BC. He thought that all matter consisted of the four elements, Air, Earth, Fire and Water, and that there were four qualities; dryness, hotness, moistness and coldness. Aristotle’s theory had 2 forces, harmony and conflict. Until the scientific revolution, Aristotle’s theory was used for nearly 2000 years. -
Isaac Newton
Isaac Newton was born on the 25th December 1642.Isaac did not specifically contribute anything to the atomic theory, but quantum mechanics helped develop the atomic theory, and it was originated souly on Newton’s mechanical work. -
Antoine Lavoisier
Antoine Lavoiser was born on the 26th August 1743 into a wealthy Paris family.He discovered that water is made of oxygen and hydrogen. He also invented the analytical balance and revealed that chemical elements were never destroyed nor created, but combined into different compounds in chemical reactions.Lavoiser published ‘Traité élémentaire de chemie ‘ in 1789 to spread his ideas and the Oxygen Theory. He named an amount of 33 elements, which most are still used to this day. -
John Dalton
John Dalton was born on the 6th September 1766 in Eaglesfield, England. He identified the hereditary nature of red-green colour blindness during his early career.The concept of Dalton’s Law of Partial Pressures was revealed in 1803.He was the first scientist to explain the behaviour of atoms in terms of the measurement of weight in the 1800’s.When studying the chemical and nature makeup of air in the early 1800s, he discovered that it was not a chemical solvent, which other scientists thougt -
Dmitri
Dmitri Mendeleev was born February 8th 1834.Dmitri Mendeleev was the scientist who invented the periodic table.
He had cards with different elements on them, and arranged them in order of atomic mass, taking notice to the fact that there were similarities in their chemical properties. This inspired the name “Periodic Table”.His first table was published in 1869. -
J.J Thomson
December 18, 1856 J.J Thomson was born in a suburb of Manchester. He discovered the electron in a sequence of experiments designed to study the nature of electric discharge in a high-vacuum cathode-ray tube, an area being investigated by multiple scientist during that time in 1897. His atomic model was made in 1904 and was named the plum pudding model. It was a round, liquidly, thick, substance whose total charge cancelled out the charge of the electrons. -
Ernest Rutherford
Ernest Rutherford was born on August 30th, 1871. Ernest Rutherford distributes his atomic theory that describes the atom as having a central positive nucleus in which is bounded by negative orbiting electrons. -
Niels Bohr
Niels Bohr was born on October 7th, 1885 in Copenhagen. In 1913 he proposed his quantized shell model of the atom, to describe how electrons are able to have stable orbits surrounding the nucleus. Bohr’s beginning point was to notice that classical mechanics, individually could never explain the atom’s stability. A stable atom has a particular size so that any equation explaining it must contain some fundamental constants or combination of constants with a measurement of length. -
Henry Moseley
Henry Moseley was born on 23rd November 1667.Henry developed X-rays to study the atomic structure. Using this, Moseley was able to determine the amount of positive charges in the nucleus of an atom, which was the first concept of the atomic number.He died on 10th of August 1915. -
Paul Dirac
Paul Dirac was born on 8t August 1902, in Bristol, England.Dirac established the most general theory of quantum mechanics and came across the equation for the electron. Paul was the first to develop the quantum field theory, which is the base for all theoretical work on sub-atomic atoms.- In 1993 he received a Nobel prize.
