The Atomic Theory

1121 Words 5 Pages
The atomic theory, the theory that all matter is made up of tiny indivisible particles (atoms). According to the modern version, the atoms of each element are effectively identical, but differ from those of other elements, and unite to form compounds in fixed proportions. To get to this conclusion the development of the atomic theory and structure of an atom started back in 465bc until now. Many chemist, philosopher and physics have contributed to this theory for example Democritus, Dalton, Thompson, Rutherford, Niels Bohr, and James Chadwick Democritus was an influential Ancient Greek pre-Socratic philosopher primarily remembered today for his formulation of an atomic theory of the universe. He was born in Abdera, Greece in 460BC and died …show more content…
Chemist John Dalton was born September 6, 1766, in Eaglesfield, England. In the 1800s, he was the first scientist to explain the behavior of atoms in terms of the measurement of weight. Dalton 's theory was different in that it had the weight of careful chemical measurements behind it. His atomic theory stated that elements consisted of tiny particles called atoms. He said that the reason an element is pure is because all atoms of an element were identical and that in particular they had the same mass. He also said that the reason elements differed from one another was that atoms of each element were different from one another; in particular, they had different masses. He also said that compounds consisted of atoms of different elements combined together. In addition, he said that chemical reactions involved the rearrangement of combinations of those atoms. Dalton 's model was that the atoms were tiny, indivisible, indestructible particles and that each one had a certain mass, size, and chemical behavior that was determined by what kind of element they were. (Francis, …show more content…
Thompson proved the plum pudding theory wrong. Rutherford was born August 30, 1871, in Spring Grove, New Zealand. A pioneer of nuclear physics and the first to split the atom, Rutherford was awarded the 1908 Nobel Prize in Chemistry for his theory of atomic structure. (Editors, n.d.) Rutherford with the assistance of Ernest Marsden and Hans Geiger performed a series of experiments using alpha particles. Rutherford aimed alpha particles at solid substances such as gold foil and recorded the location of the alpha particle "strikes" on a fluorescent screen as they passed through the foil. To the experimenters’ amazement, although most of the alpha particles passed unaffected through the gold foil as expected, a small number of particles were deflected at an angle, and a few ricocheted straight back. Rutherford concluded that the atom consisted of a small, dense, positively charged nucleus in the center of the atom with negatively charged electrons surrounding it. The discovery of the nucleus is considered Rutherford’s greatest scientific work. (Development of the Atomic Theory,

Related Documents