Do you know what the Rutherford's atomic model? It was the result of an experiment that showed that Thomson's model was wrong and that electrons were not found only in an environment with a positive electrical charge.
Rutherford Atomic Model
El Rutherford Atomic Model, which also received the name of planetary model was created in the year 1911. Starting from studies made around the Thomson model that was based on the affirmation that the electrons were in an environment of positive electric charge, two assistants of Rutherford, Geiger and Marsden, devised in the year 1909 an experiment.
Such a study, on which the atomic theory of Rutherford which was named the gold foil test, proved Thomson's model wrong, as they were able to show that the atom had a structure with a large part of positive charge. This study, which was devised and directed by Rutherford, gave rise to conclusions that originated what was called Rutherford's atomic model, in 1911.
The Gold Leaf Experiment
It was about a number of experiences carried out between 1909 and 1913, in the physics laboratories of the University of Manchester by two researchers, Hans Geiger and Ernest Marsden, who were disciples of Ernest Rutherford and under his direction. The relevance of these experiments is that their deductions and considerations gave rise to a new and versatile atomic model.
The experience lies in bombarding a narrow gold foil 100 nm thick with alpha particles. Alpha particles were ions, that is, atoms without electrons, because they only contained protons and neutrons and, consequently, a positive electric charge. Because of this, if Thomson's atomic model were true, the alpha particles of ions would pass through the gold atoms in a straight line.
In order to study the effects of the deflection that was caused by the alpha particles, a fluorescent filter of zinc sulfide was placed around the thin gold foil, and it was possible to see that, despite some particles, they passed through the gold atoms. gold in a straight line, others deviated in random paths.
Conclusions of the Experiment
As a result of these investigations, they left aside the predecessors of atomic models with which it was thought that the electrical charge with a positive sign was uniformly distributed in the atoms, and that this made it easier to transfer it, because its electrical charge did not it was going to be so powerful at a certain point.
Because some alpha particles deflected in random directions, the results of these experiments were unexpected and led Rutherford to believe that the atom must have a center with a strong positive electrical charge, which in the case of an alpha particle to cross it was rejected by that central axis.
Taking into account the sum of reflected particles and those that suffered from this effect, it was possible to establish the diameter of that central axis, comparing it with the orbit of the electrons in its environment and it was also possible to reach the conclusion that most of the space of an atom is empty.
Likewise, it was shown that several of the alpha particles were deflected from their path by the gold foil at very narrow angles, and for this reason it was concluded that the positive electric charge in an atom is not evenly distributed. uniform. The positive electrical charge on an atom is concentrated to a very small amount.
Finally, because a few of the alpha particles were deflected backwards, that is, as if a rebound phenomenon had occurred, it was possible to establish the amount of space occupied by charged particles with positive electrical energy in an atom. , turning out to be very small when compared to the total space of an atom.
As a result of these relevant findings, it became evident in Rutherford's mind that the atomic model, as it was known up to that time, was wrong, so he worried about creating a new atomic model, taking into account the following considerations:
Basic Principles of Rutherford's Atomic Model
Particles that have a positive electrical charge are found in a very small amount compared to the size of the atom.
A large portion of the atom's mass is located in a small central space. Rutherford stopped short of calling it a nucleus in his initial notes, but he used the term beginning in 1912.
Electrons with an electrical charge of negative sign, hover around the nucleus.
Electrons rotate at high speeds around the nucleus and in circular paths that he named orbits.
Electrons charged with electrical energy of negative sign as the nucleus with electrical charge of positive sign are held together by an electrostatic attractive force.
Acceptance of the Rutherford Atomic Model
Rutherford's atomic model met with immediate approval from the scientific community and was the starting point for a view of the atom with various subatomic particles. Researchers years later were able to establish the number of electrons and the atomic number of each element.
Culturally, despite subsequent new findings, the Rutherford-Bohr planetary paradigm model is the one in the consciousness of many people and remains the simplest way to demonstrate how an atom works. , with its nucleus of protons, while the neutrons and electrons are circling in orbits that rotate around them.
Limitations and Errors in the Rutherford Model
Although Rutherford's atomic model resulted in a scientific breakthrough for physics, it was not a neat or perfect model, moreover, according to the laws explained in the Isaac Newton Biography such a configuration was an inadmissible question and also did not explain a very relevant element of Maxwell's laws. In this sense, Rutherford's atomic model could not explain issues such as:
The reason why a number of positive electric charges remained attached in the nucleus. If we follow the electrical theory, charges with a positive sign must repel each other. But the nucleus is the place of the grouping of several protons.
Another contradiction of this atomic model was the fundamental laws of electrodynamics, since by establishing that electrons with a negative electrical charge rotate around the nucleus, according to Maxwell's laws, they would have to emanate electromagnetic radiation. That emission should consume energy and cause electrons to collide with the nucleus. Therefore, he could not explain why the atom remained stable.
Additional considerations of the Rutherford Model
Although Rutherford's atomic model was soon changed to the Bohr Atomic Model, with which some of the problems and contradictions of the first were resolved, the new conceptualization of the atomic model was revolutionary and constituted the beginning of a new vision of the study of the atom and its scientific applications, for which Rutherford is considered to be the father of nuclear physics.
Who was Ernest Rutherford?
Ernest Rutherford was born on August 30, 1871, he was a native of New Zealand. His father was a farmer and his mother was a school teacher. His parents were British emigrants who had settled in New Zealand years earlier.
He attended school and college in New Zealand, but in 1895 he was awarded a scholarship to Cambridge, England, where he befriended JJ Thomson, who was the one who discovered the electron and created the model of the atom that has your name.
Thanks to the recommendation given by Thomson himself, Rutherford came to occupy a chair at a university in Canada, where he was able to study the chemistry of radioactive substances, work for which he was awarded the Nobel Prize in Chemistry in 1908.
Rutherford returned to the United Kingdom in 1907, heading to the University of Manchester, where he was able to make his greatest contributions to science. In the year 1908 and in later years Rutherford, with the assistance of his collaborators, was able to carry out the experiments that led him to create a new and versatile atomic model in 1911.
In 1914 he had the honor of being appointed a knight of the English crown, for his work in the war that contributed to the detection of submarines through sonar and in 1917 he was appointed director of the Cavendish laboratory in Cambridge, succeeding in the position to JJ Thomson. Under his direction, many of his collaborators managed to obtain several Nobel Prizes.
Thanks to his innumerable successes, in 1931 he was named Baron Rutherford of Nelson, a few years before his death in 1937.
Scientific Contributions
Rutherford made several scientific contributions, beginning with his work with X-rays in gases, which served as the basis for JJ Thomson's discovery of the electron. His research on the radioactivity of Uranium made it possible for him to detect the existence of two kinds of radiation, alpha rays and beta rays. But ultimately, his most successful contribution was his atomic model.
