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460 BCE
democtatus
This is Democritus' atomic theory exactly:
1.All matter consists of invisible particles called atoms.
2. Atoms are indestructible.
3. Atoms are solid but invisible.
4. Atoms are homogenous.
5. Atoms differ in size, shape, mass, position, and arrangement.
->Solids are made of small, pointy atoms.
->Liquids are made of large, round atoms.
->Oils are made of very fine, small atoms that can easily slip past each other. -
DALTONS MODEL
Dalton's model of the atom. John Dalton proposed that all matter is composed of very small things which he called atoms. This was not a completely new concept as the ancient Greeks (notably Democritus) had proposed that all matter is composed of small, indivisible (cannot be divided) objects. -
plum rudding model
The Plum Pudding Model is a model of atomic structure proposed by J.J. Thomson in the late 19th century. Thomson had discovered that atoms are composite objects, made of pieces with positive and negative charge, and that the negatively charged electrons within the atom were very small compared to the entire atom. -
Bohr's model
In atomic physics, the Rutherford–Bohr model or Bohr model, introduced by Niels Bohr in 1913 on September 7th, depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus—similar in structure to the solar system, but with attraction provided by ...
