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400 BCE
Democritus-The Atom
Democritus's model stated that matter consists of invisible particles called atoms and avoid (empty space).
Democritus greatest contribution to modern science was arguably the atomic theory he elucidated. He was the first of all the philosophers and scientist to talk about the atom, disproving the 4 elements of the matter.
The main error he has is that he just state that there was undivisible. -
Solid Sphere Mode-John Dalton
In 1803 Dalton discovered that oxygen combined with either one or two volumes of nitric oxide.
Dalton's atomic theory proposed:
-All matter is composed of extremely small particles called atoms, which cannot be subdivided, created, or destroyed.
-Atoms of a given element are identical in their physical and chemical properties.
The two main error in Daltons atomic model were:
-That the atom is indivisible.
-And that all the parts of the atom were the same size. -
Plum pudding model-J.J. Thompson
Atoms are uniform spheres of positively charged matter in which electrons are embedded. Popularly known as the plum pudding model.
Thomson is credited with identifying electrons as particles of an atom.
The main problem with Bohr's model is that it works very well for atoms with only one electron, like H or He+, but not at all for multi-electron atoms. -
Atomic or Nuclear Model- Ernest Rutherford
This model that the atom is mostly empty space.
The main contribution of this atomic model was separating the electron from the protons (nucleus), also representing the atom as mostly empty space.
This model is unsustainable, because it doesn’t have neutrons this model also tell us that the electron travels in defined orbits or paths, and it doesn’t explain the energy “jumps”. -
Planetary Lever-Niels Bohr
The Bohr model of the atom, a radical departure from earlier, classical descriptions, was the first that incorporated quantum theory and was the predecessor of wholly quantum-mechanical models. Niels Bohr developed the "Planetary" model of the atom.
The main problem with Bohr's model is that it works very well for atoms with only one electron, like H or He+, but not at all for multi-electron atoms. -
Electron Cloud model-Schrödinger
The Schrödinger model assumes that the electron is a wave and tries to describe the regions in space, or orbitals, where electrons are most likely to be found. Describes the probability that an electron can be found in a given region of space at a given time. Where the cloud is most dense, the probability of finding the electron is greatest, and conversely, the electron is less likely to be in a less dense area of the cloud. This model introduced the concept of sub-energy levels.
