Who discovered the atom and when?
Who discovered the atom and when?
The discovery of the atom was the first step in the way of understanding the microcosm. This happened only in the late 19th century, in spite of the fact that the existence of the atom was predicted by ancient Greek scientists.
150 years ago, scientists believed that the atoms that make up all substances are indivisible by nature. Modern science has long shown that this is not so. It all started with the discovery of the electron.
The discovery of the electron
At the end of the 19th century, sciencea real revolution. The famous scientist J.J. Thomson (Lord Kelvin) discovered an electron, a microparticle possessing a negative charge. According to his theory, electrons are present in every atom. The lack of necessary equipment did not allow to determine exactly how these particles are located in the atom and whether they move. Physicists could only indulge in philosophical arguments on this topic. Lord Kelvin and proposed the first model of the atom. According to his model, the atom is a fraction of the positively charged substance in which the electrons are located. Many compare this atom with a cake, in which sprinkled with raisins.Rutherford's experiments
The English physicist Ernest Rutherford was also engagedstudies of the atom. His experiments destroyed one of the postulates of the physics of the microcosm of the time. This postulate was that the atom is an indivisible particle of matter. By that time, the natural radioactivity of some chemical elements was already discovered. One of them, Rutherford and used for experience. The results of the experiment made it possible to create a new model of the atom. Rutherford irradiated the gold foil with alpha particles. It turned out that some of them could go through the foil freely, and some scattered at different angles. If the gold atoms had the structure proposed by Thomson, the alpha particle, which has a fairly large diameter, could only be reflected at right angles. Thomson's model was unable to explain this phenomenon, so Rutherford proposed his model, which he called planetary. According to her, the atom is a nucleus around which electrons rotate. One can give an analogy to the solar system: the planets revolve around the Sun. Electrons move in their own orbits.Quantum theory of Bohr
The planetary model of the atom was in good agreementwith many experiments, but she could not explain the long existence of the atom. It's all about outdated classical ideas about the atom. Electron, moving in orbit, must radiate (give away) energy. After a short time (about 0.00000001 seconds), it must fall on the atom, as a result of which the existence of the latter will cease. But why then do we all still exist and did not break up into tiny particles? The answer to this question was given by Bohr's quantum theory. Today, there are many models of the atom and the atomic nucleus. Each of them has its own shortcomings and advantages. Humanity will never be able to create a perfect model that would explain the amazing phenomena taking place in it.
