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History of atomic theory. The current theoretical model of the atom involves a dense nucleus surrounded by a probabilistic "cloud" of electrons. Atomic theory is the scientific theory that matter is composed of particles called atoms. The definition of the word "atom" has changed over the years in response to scientific discoveries.
But this ancient idea was based in philosophical reasoning rather than scientific reasoning. Modern atomic theory is not based on these old concepts. [1] [2] In the early 19th century, the scientist John Dalton (1766–1844) found evidence that matter really is composed of discrete units, and so applied the word atom to those units. [3]
Atomism (from Greek ἄτομον, atomon, i.e. "uncuttable, indivisible") [1][2][3] is a natural philosophy proposing that the physical universe is composed of fundamental indivisible components known as atoms. References to the concept of atomism and its atoms appeared in both ancient Greek and ancient Indian philosophical traditions.
J. Robert Oppenheimer. J. Robert Oppenheimer (born Julius Robert Oppenheimer; / ˈɒpənhaɪmər / OP-ən-hy-mər; April 22, 1904 – February 18, 1967) was an American theoretical physicist who served as the director of the Manhattan Project 's Los Alamos Laboratory during World War II. He is often called the "father of the atomic bomb " for ...
3D animation of an atom incorporating the Rutherford model. The atomic nucleus shown expanded more than 10,000 times its size relative to the atom; electrons have no measurable diameter. The Rutherford model was devised by Ernest Rutherford to describe an atom. Rutherford directed the Geiger–Marsden experiment in 1909, which suggested, upon ...
Werner Heisenberg. Werner Karl Heisenberg (/ ˈhaɪzənbɜːrɡ /; [2] German: [ˈvɛʁnɐ kaʁl ˈhaɪzn̩bɛʁk] ⓘ; 5 December 1901 – 1 February 1976) [3] was a German theoretical physicist, one of the main pioneers of the theory of quantum mechanics, and a principal scientist in the Nazi nuclear weapons program during World War II.
Thomson's prize-winning master's work, Treatise on the motion of vortex rings, shows his early interest in atomic structure. [4] In it, Thomson mathematically described the motions of William Thomson's vortex theory of atoms. [18] Thomson published a number of papers addressing both mathematical and experimental issues of electromagnetism.
1924 Satyendra Bose and Albert Einstein introduce Bose–Einstein statistics. 1925 George Uhlenbeck and Samuel Goudsmit postulate electron spin. 1925 Pierre Auger discovers the Auger process (2 years after Lise Meitner) 1925 Werner Heisenberg, Max Born, and Pascual Jordan formulate quantum matrix mechanics.