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Democritus called his atomic model "matter atomos".
Democritus thought that atoms were uniform, solid, hard, incompressible, and indestructible, and that they travelled in an endless number of directions across empty space until they were stopped. The varied qualities of matter were defined by differences in atomic form and size. -
The main contribution of this model is the creation of the atomic theory by itself, because before of him, the atomic model didn´t exist.
The only thing wrong with this theory is that atoms are actually divisible, the things that are not divisible are electrons, neutrons, and protons. -
Name of the atomic model: Solid-sphere model
Dalton’s atomic model was based on the Greek idea of atoms, he pictured them as spheres of different colors and shapes, and said that atoms of the same element were not the same as atoms of another element. -
It recognized atoms of a particular element differ from other elements.
Dalton said it was indivisible, so it didn’t have any subatomic particles or empty space, which we know is wrong. -
Name of the atomic model: plum pudding model
J.J. Thompson proposed a model of the atom that consisted of more than one fundamental unit. By the late 1890s, Thompson began conducting experiments using a cathode ray tube known as the Crookes’ Tube. Thomson observed that these rays could be deflected by electric and magnetic fields. He concluded that rather than being composed of light, they were made up of negatively charged particles he called «corpuscles» later called «electrons». -
This model incorporated new discoveries, like the existence of the electron, and the notion of the atom as a non-inert, divisible mass. Making scientists understand that atoms were composed of smaller units of matter and that all atoms interacted with each other through many different forces.
The model was wrong because there was the problem of demonstrating that the atom possessed a uniform positive background charge, which later was known as the «Thomson Problem». -
Name of the model: nuclear model
Hans Geiger and Ernest Marsden conducted an experiment called «gold foil experiment» where they measured the scattering pattern of the alpha particles with a fluorescent screen. However, they noted instead that while most shot straight through some of them were scattered in various directions, with some going back in the direction of the source
This experiment implied that the positive charge in the atom was not widely dispersed, but concentrated in a tiny volume -
Ernest Rutherford interpreted the Geiger-Marsden experiments and rejected Thomson’s model of the atom. This came to be known as the Rutherford Model of the atom.
Although Rutherford did a great job in his experiments, his idea was rejected because he couldn't explain why negatively charged electrons remain in orbit when they should instantly fall into the positively charged nucleus. -
Bohr was the first to discover that electrons travel in separate orbits around the nucleus and that the number of electrons in the outer orbit determines the properties of an element. -
It was known as the planetary model.
In the Bohr model of the atom, electrons travel in defined circular orbits around the nucleus. The orbits are labeled by an integer, the quantum number n. Electrons can jump from one orbit to another by emitting or absorbing energy.
What was wrong in this atomic model is that it does not account for sublevels (s,p,d,f), orbitals or elecrtron spin. -
Erwin Schrödinger showed that the quantization of the hydrogen atom's energy levels that appeared in Niels Bohr's atomic model could be calculated from the Schrödinger equation, which describes how the wave function of a quantum mechanical system (in this case, a hydrogen atom's electron) evolves. -
It is known as the quantum model.
It is a model of the atom that derives from the Schrödinger wave equation and deals with probabilities. wave function: Give only the probability of finding an electron at a given point around the nucleus.
So far nothing wrong with this atomic model has been found.