-
400 BCE
Democritus model
He came up with the first atomic theory, in which matter could not be divided into small pieces forever. Eventually, it would become the smallest piece of matter possible, which he called Atomos (atom). Democritus described atoms as a small particles, made up of the same materials, but came in different shapes and sizes. What was wrong with this model is the he said that the atom doesn't had an internal structure but now we know that its formed of a nucleus and electrons -
"Billiard ball" model
Dalton's atomic theory is that all matter is made of indivisible and indestructible atoms, all atoms of a given element are identical in mass and size, and a chemical reaction is a rearrangement of atoms. Something wrong about this theory was that he said that atoms of the same elements have the same mass and size but its not always like that -
"Plum pudding" model
The Thomson atomic model is the description of the inner part of atoms this was proposed in 1900’s by William Thomson and was supported by Joseph Thomson who discovered the electron in 1897. This model is popularly known as the plum pudding model, in this the electrons describe orbits about a tiny positive nucleus. Neutrons weren't part of this model. This is a reason why this model isn't completely wrong -
Rutherford model
The model described the atom as a tiny, dense, positively charged core called a nucleus, in which nearly all the mass is concentrated, around which the light called electrons, circulate at some distance, The atomic model failed to explain the stability of electrons in a circular path. As the electrons move in circular path, they should undergo acceleration and radiate energy. The radiation of energy would result in the electron losing energy and collide with the nucleus, -
Bohr model
According to Bohr Atomic model, a small positively charged nucleus is surrounded by revolving negatively charged electrons in fixed orbits. He concluded that electron will have more energy if it is located away from the nucleus whereas the electrons will have less energy if it located near the nucleus. -
Schrödinger model
Schrödinger used mathematical equations to describe the likelihood of finding an electron in a certain position. This atomic model is known as the quantum mechanical model of the atom. Unlike the Bohr model, the quantum mechanical model does not define the exact path of an electron, but rather, predicts the odds of the location of the electron. -
Conclusions Part 2
In conlusion, there are many models of the atom through time, everyone of them showing something new and inovating in the model, ending with the complete and acurate model. Even tough all the models had some flaws without them we wouldn't understand the real structure of the atom and how it works, so we must understand each one of them to understand the reality of the atom. -
Conclusions
We learn that there are many kinds of atomic models like Dalton’s, Thompson’s, Rutherford’s and Shrodinger’s and each one of them has its own characteristic and its own shape, name and the way particles move in it. (David)
In conclusion, thanks to all this we know the different models and the change they have had and the great impact it has today. Everyone has its own characteristics and their specific symbol. It has evolved too much until we have the model that we have now days. (Sofía)
