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400
who came up with the name
Democritus of Adbera
24 Oct 400 Democritus of Adbera is credited for the term atomos, meaning indivisible. He was the first to identify the possibility of an atom and deem it as the smallest piece of matter. -
Period: 400 to
atom
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Dalton
John Dalton
24 Oct 1803 John Dalton is credited as the father of the modern atomic theory. The theory is composed of five parts, which includes elements being composed of atoms and that element's atoms are identical in mass. -DL (Because timetoast doesn't allow timespans in a good way, the correct span for this information is 1803-1808) -MW -
Dalton
John Dalton's Atomic Theory
24 Oct 1803 The atomic theory, as proposed by John Dalton, is composed of five parts.1) Elements are composed of extremely small particles known as atoms.2) Atoms of a given element are identical in size, mass, and other properties; atoms of different elements are different3) Atoms cannot be subdivided, created, or destroyed.4) Atoms of different compounds combine in simple, whole-number ratios to form chemical compounds.5) In chemical reactions, atoms are combined, -
Dalton
ohn Dalton's Solid Sphere Model
25 Oct 1803 The solid sphere model was John's Dalton's explanation of the atom. It was a solid, indestructible sphere. It didn't include a nucleus or subatomic particles. However, it didn't explain a lot, and was quickly replaced by other things. -
Thomson
Joseph John Thomson Joseph John Thomson is credited with describing the nature of cathode rays. He also created the plum pudding model of the atom and discovered the electron.-DL -
Thomson
JJ Thomson's plum pudding model. The plum pudding model, proposed by JJ Thomson, was seen as the atom before the discovery of the atomic nucleus. The model is composed of electrons surrounded by positive charge to balance the negative charges. The "plums" were neutralized by the "pudding". This model of the atom was disproved in 1909, by Ernest Rutherford. -
Rutherford
Ernest Rutherford's Gold foil Experiment The Gold foil experiment consisted of a series of tests in which positive charges were sent through a layer of gold foil. The expected result was the the charges would just pass through because of the theory of the plum pudding model. However, the results were unexpected, as various charges were aimed all directions, bouncing off of something in teh atom. This led to the discovery of the atomic nucleus, the planetary model of the atom, and -
Rutherford
Ernest Rutherford Ernest Rutherford is credited with the gold foil experiment. He stated that atoms have a small positively charged nucleus, and the remainder is empty space. He also predicted the existence of neutrons. (because timetoast doesn't allow for timespans, the correct labeling for this is 1911-1918) -MW -
Bohr
Niels Bohr
Niels Bohr is credited with the planetary model of the atom. He also stated that electrons traveled in specified energy levels and that spectrum lines are produced when electrons move. -MW