Discoveries in the field of atomic structure have become an important step in the development of physics. Rutherford's model was of great importance. The atom as a system and the particles that make it up has been studied more accurately and in detail. This led to the successful development of such a science as nuclear physics.
Ancient ideas about the structure of matter
The assumption that the surrounding bodies are composed of the smallest particles was made in ancient times. The thinkers of that time represented the atom as the smallest and indivisible particle of any substance. They argued that there is nothing in the universe smaller than an atom. Such views were held by the great ancient Greek scientists and philosophers - Democritus, Lucretius, Epicurus. The hypotheses of these thinkers are today united under the name "antique atomism".
Medieval performances
The times of antiquity have passed, and in the Middle Ages there were also scientists who made various assumptions about the structure of substances. However, the predominance of religious philosophical views and the power of the church in that period of history are at the rootsuppressed any attempts and aspirations of the human mind to materialistic scientific conclusions and discoveries. As you know, the medieval Inquisition behaved very unfriendly with representatives of the scientific world of that time. It remains to be said that the then bright minds had an idea that came from antiquity about the indivisibility of the atom.
18-19th century studies
The 18th century was marked by serious discoveries in the field of the elementary structure of matter. Largely thanks to the efforts of such scientists as Antoine Lavoisier, Mikhail Lomonosov and John D alton. Independently of each other, they were able to prove that atoms really exist. But the question of their internal structure remained open. The end of the 18th century was marked by such a significant event in the scientific world as the discovery of the periodic system of chemical elements by D. I. Mendeleev. This was a truly powerful breakthrough of that time and lifted the veil over the understanding that all atoms have a single nature, that they are related to each other. Later, in the 19th century, another important step towards unraveling the structure of the atom was the proof that any of them contains an electron. The work of the scientists of this period prepared fertile ground for the discoveries of the 20th century.
Thomson's experiments
English physicist John Thomson proved in 1897 that atoms contain electrons with a negative charge. At this stage, the false ideas that the atom is the limit of the divisibility of any substance were finally destroyed. HowThomson was able to prove the existence of electrons? In his experiments, the scientist placed electrodes in highly rarefied gases and passed an electric current. The result was cathode rays. Thomson carefully studied their features and found that they are a stream of charged particles that move at great speed. The scientist was able to calculate the mass of these particles and their charge. He also found out that they cannot be converted into neutral particles, since the electric charge is the basis of their nature. This is how electrons were discovered. Thomson is also the creator of the world's first model of the structure of the atom. According to it, an atom is a bunch of positively charged matter, in which negatively charged electrons are evenly distributed. This structure explains the general neutrality of atoms, since opposite charges balance each other. The experiments of John Thomson became invaluable for the further study of the structure of the atom. However, many questions remained unanswered.
Rutherford Research
Thomson discovered the existence of electrons, but he failed to find positively charged particles in the atom. Ernest Rutherford corrected this misunderstanding in 1911. During experiments, studying the activity of alpha particles in gases, he discovered that there are positively charged particles in the atom. Rutherford saw that when rays pass through a gas or through a thin metal plate, a small number of particles sharply deviate from the trajectory of motion. They were literally thrown back. The scientist guessed thatthis behavior is explained by the collision with positively charged particles. Such experiments allowed the physicist to create Rutherford's model of the structure of the atom.
Planetary Model
Now the scientist's ideas were somewhat different from the assumptions made by John Thomson. Their models of atoms also became different. Rutherford's experience allowed him to create a completely new theory in this area. The discoveries of the scientist were of decisive importance for the further development of physics. Rutherford's model describes an atom as a nucleus located in the center, and electrons moving around it. The nucleus has a positive charge, and the electrons have a negative charge. Rutherford's model of the atom assumed the rotation of electrons around the nucleus along certain trajectories - orbits. The discovery of the scientist helped explain the reason for the deviation of alpha particles and became the impetus for the development of the nuclear theory of the atom. In Rutherford's model of the atom, there is an analogy with the movement of the planets of the solar system around the sun. This is a very accurate and vivid comparison. Therefore, the Rutherford model, in which the atom moves around the nucleus in an orbit, was called planetary.
Works by Niels Bohr
Two years later, the Danish physicist Niels Bohr tried to combine ideas about the structure of the atom with the quantum properties of the light flux. Rutherford's nuclear model of the atom was put by scientists as the basis of his new theory. According to Bohr, atoms revolve around the nucleus in circular orbits. Such a trajectory of motion leads to accelerationelectrons. In addition, the Coulomb interaction of these particles with the center of the atom is accompanied by the creation and consumption of energy to maintain the spatial electromagnetic field arising from the movement of electrons. Under such conditions, negatively charged particles must someday fall onto the nucleus. But this does not happen, which indicates the greater stability of atoms as systems. Niels Bohr realized that the laws of classical thermodynamics described by Maxwell's equations do not work in intraatomic conditions. Therefore, the scientist set himself the task of deriving new patterns that would be valid in the world of elementary particles.
Bohr's postulates
Largely due to the fact that Rutherford's model existed, the atom and its components were well studied, Niels Bohr was able to approach the creation of his postulates. The first of them says that the atom has stationary states, in which it does not change its energy, while the electrons move in orbits without changing their trajectory. According to the second postulate, when an electron moves from one orbit to another, energy is released or absorbed. It is equal to the difference between the energies of the previous and subsequent states of the atom. In this case, if the electron jumps to an orbit closer to the nucleus, then energy (photon) is emitted, and vice versa. Despite the fact that the movement of electrons bears little resemblance to an orbital trajectory located strictly in a circle, Bohr's discovery provided an excellent explanation for the existence of a ruledspectrum of the hydrogen atom. Around the same time, physicists Hertz and Frank, who lived in Germany, confirmed the teachings of Niels Bohr about the existence of stationary, stable states of the atom and the possibility of changing the values of atomic energy.
Cooperation of two scientists
By the way, Rutherford could not determine the charge of the nucleus for a long time. Scientists Marsden and Geiger tried to re-check the statements of Ernest Rutherford and, as a result of detailed and careful experiments and calculations, came to the conclusion that it is the nucleus that is the most important characteristic of the atom, and all its charge is concentrated in it. Later it was proved that the value of the charge of the nucleus is numerically equal to the ordinal number of the element in the periodic system of elements of D. I. Mendeleev. Interestingly, Niels Bohr soon met Rutherford and fully agreed with his views. Subsequently, scientists worked together for a long time in the same laboratory. Rutherford's model, the atom as a system consisting of elementary charged particles - all this Niels Bohr considered fair and forever put aside his electronic model. The joint scientific activity of scientists was very successful and bore fruit. Each of them delved into the study of the properties of elementary particles and made significant discoveries for science. Rutherford later discovered and proved the possibility of nuclear decomposition, but this is a topic for another article.
