What holds an electron in an atom in the orbit of the atomic nucleus?
At first glance, especially if you look at the cartoon version of the atom I described earlier with all its flaws, electrons orbiting around the nucleus look the same as planets orbiting the sun. And it seems that the principle of these processes is the same. But there's a catch.
Fig 1
What keeps the planets in orbit around the Sun? IN Newtonian gravity(Einstein’s is more complicated, but we don’t need it here) any pair of objects is attracted to each other by gravitational interaction, proportional to the product of their masses. Specifically, the Sun's gravity pulls the planets toward it (with a force inversely proportional to the square of the distance between them. That is, if the distance is halved, the force quadruples). The planets also attract the Sun, but it is so heavy that this has almost no effect on its movement.
Inertia, the tendency of objects to move in straight lines in the absence of other forces acting on them, works against gravitational attraction, and as a result, the planets move around the Sun. This can be seen in Fig. 1, which shows a circular orbit. Typically these orbits are elliptical - although in the case of planets they are almost circular, since that is how they formed solar system. For various small rocks (asteroids) and blocks of ice (comets) moving in orbit around the Sun, this is no longer the case.
Likewise, all pairs of electrically charged objects attract or repel each other, with a force also inversely proportional to the square of the distance between them. But unlike gravity, which always pulls objects together, electrical forces can either attract or repel. Objects that have the same charge, positive or negative, repel each other. And a negatively charged object attracts a positively charged object, and vice versa. Hence the romantic phrase “opposites attract.”
Therefore, positively charged atomic nucleus at the center of the atom attracts lightweight electrons moving at the outskirts of the atom towards itself, much like the Sun attracts the planets. Electrons also attract the nucleus, but the mass of the nuclei is so much greater that their attraction has almost no effect on the nucleus. Electrons also repel each other, which is one of the reasons they don't like to spend time close to each other. One could think of the electrons in an atom as moving in orbit around the nucleus in much the same way as planets move around the sun. And at first glance, this is exactly what they do, especially in the cartoon atom.
But here's the catch: it's actually a double trick, and each of the two tricks has the opposite effect of the other, causing them to cancel each other out!
Double catch: how atoms differ from planetary systems
Fig 2
The first catch: unlike planets, electrons moving in orbit around the nucleus must emit light (more precisely, electromagnetic waves, one example of which is light). And this radiation should cause the electrons to slow down and fall in a spiral towards the nucleus. In principle, in Einstein's theory there is a similar effect - planets can emit gravitational waves. But it is extremely small. Unlike the case with electrons. It turns out that the electrons in an atom must very quickly, in a small fraction of a second, fall in a spiral onto the nucleus!
And they would have done so if not for quantum mechanics. The potential disaster is depicted in Fig. 2.
The second catch: but our world works according to the principles quantum mechanics! And it has its own amazing and counterintuitive principle of uncertainty. This principle, which describes the fact that electrons are waves just like particles, deserves its own article. But here's what we need to know about him for today's article. General consequence This principle is that it is impossible to know all the characteristics of an object at the same time. There are sets of characteristics for which measuring one of them makes the others uncertain. One case is the location and speed of particles such as electrons. If you know exactly where the electron is, you don't know where it's going, and vice versa. It is possible to reach a compromise and know with some accuracy where it is and know with some accuracy where it is going. In an atom, this is how everything works out.
Suppose an electron falls in a spiral onto a nucleus, as in Fig. 2. As it falls, we will know its location more and more accurately. Then the uncertainty principle tells us that its speed will become more and more uncertain. But if the electron stops at the nucleus, its speed will not be indefinite! That's why he can't stop. If he suddenly tries to fall down in a spiral, he will have to move faster and faster randomly. And this increase in speed will take the electron away from the nucleus!
So the downward spiral trend will be counteracted by the upward trend. fast movement according to the uncertainty principle. Balance is found when the electron is located at a preferred distance from the nucleus, and this distance determines the size of the atoms!
Fig 3
If the electron is initially far from the nucleus, it will move towards it in a spiral, as shown in Fig. 2, and emit electromagnetic waves. But as a result, its distance from the nucleus will become small enough for the uncertainty principle to prohibit further approach. At this stage, when a balance has been found between radiation and uncertainty, the electron organizes a stable “orbit” around the nucleus (more precisely, an orbital - this term was chosen to emphasize that, unlike planets, the electron, due to quantum mechanics, does not have such orbits as planets have). The radius of the orbital determines the radius of the atom (Fig. 3).
Another feature – electrons belonging to fermions – forces electrons not to descend to the same radius, but to line up in orbitals of different radii.
How big are atoms? Approximation based on the uncertainty principle
In fact, we can roughly estimate the size of an atom using just calculations for electromagnetic interactions, electron mass and the uncertainty principle. For simplicity, we will perform calculations for the hydrogen atom, where the nucleus consists of one proton, around which one electron moves.
The uncertainty principle states:
$$display$$m_e (Δ v) (Δ x) ≥ ℏ$$display$$
where ℏ is Planck's constant h divided by 2 π. Note that he says that (Δ v) (Δ x) cannot be too small, which means that both definitenesses cannot be too small, although one of them can be very small if the other is very large.
When an atom settles into its preferred ground state, we can expect the ≥ sign to turn into a ~ sign, where A ~ B means that "A and B are not exactly equal, but not very different either." This is a very useful symbol for ratings!
For a hydrogen atom in the ground state, in which the position uncertainty Δx will be approximately equal to the atom radius R, and the velocity uncertainty Δv will be approximately equal to the typical speed V of the electron around the atom, we obtain:
How to find out R and V? There is a relationship between them and the force that holds the atom together. In non-quantum physics, an object of mass m, located in a circular orbit of radius r, and moving with speed v around a central object attracting it with a force F, will satisfy the equation
This is not directly applicable to an electron in an atom, but it works approximately. The force acting in an atom is the electrical force with which a proton with a charge of +1 attracts an electron with a charge of -1, and as a result the equation becomes
where k is the Coulomb constant, e is the unit of charge, c is the speed of light, ℏ is Planck’s constant h divided by 2 π, and α is the constant we defined fine structure, equal to . We combine the two previous equations for F, and the estimated relationship is as follows:
Now let's apply this to an atom, where v → V, r → R, and m → m e. Let's also multiply the upper equation by . This gives:
In the last step we used our uncertainty relation for the atom, . Now we can calculate the radius of the atom R:
And it turns out to be almost accurate! Such simple estimates will not give you exact answers, but they will provide a very good approximation!
What good readers there are! They not only love and respect natural history teachers, but also know how Bohr’s atomic model explains that electrons do not fall on nuclei.
Or are they falling?
The question “why don’t electrons fall on nuclei” does not mention the fact that we're talking about exclusively about the one-electron atom. Bohr's atomic model (and old quantum mechanics in general) says nothing about the stability of many-electron atoms and molecules. The fact that the “fall” does not occur in a one-electron atom does not guarantee the same for other systems. If you are experts in old quantum theory and undertook to help natural history teachers, then bring your reasoning to the end. For example, I need proof general position unknown.
P.S. The Bohr model can fairly well describe the singlet and triplet states of simple diatomic molecules. We discovered this, however, only in 2005, but better late than never. The construction is quite frontal:
Works a little worse than the original GL theory about chemical bond. By construction, electrons are guaranteed not to fall on nuclei (hurray!), but the model itself is far in spirit from quantizing adiabatic invariants. I saw something similar done for the H2+ ion, but in a more sophisticated version. The idea was to quantize not the integrals themselves, but their sum:
They probably would have been doing this for twenty or thirty years if Schrödinger had not come up with his equation. Figure out how to do even this little thing with the old one quantum mechanics- not easy. Pearson - luminary quantum chemistry, member National Academy, Herschbach - besides Nobel laureate. There is much more in front of you difficult task. We need to create what Bohr failed to achieve: a working general theory multielectronic systems. After this, all that’s left is to prove general case stability of all electron orbits.
Good luck.
P.P.S. Since I have no desire to debate the topic that the stability of many-particle Coulomb systems in (new) quantum mechanics is explained by the self-adjoint of the Hamiltonian, the phases of the Moon, etc., commentators are advised to read
By the way, why the Heisenberg uncertainty principle alone does not explain the stability of the atom (as claimed by the cream of the Internet issued by Google) is written on pp. 554-555 of this essay, part I.
Explanation and understanding are not the same thing. Dilthey proved this once and for all.
S. Kurginyan
Quantum mechanics based on the theory of relativity and physical chemistry, based on quantum mechanics, “explained” the atom by “smearing” electrons in “clouds of orbitals.” There are postulates, laws of numbers, but no explanation natural laws“why is this so” and, moreover, there is a complete lack of understanding of the laws of motion of electrons in an atom. The paradox is that even the appearance of a hydrogen atom contradicts the law electrical interaction charges. The electron must be attracted by interaction forces in emptiness or physical vacuum to the proton, so it must “fall” onto it and the charges must “discharge”. Why does the electron not “fall”, but rather begin to rotate around the proton and form a hydrogen atom? Let’s try to dispel the nebula of the clouds of “orbitals” and come closer to understanding what can be considered the orbit of an elementary particle, what the type and location of orbits are, and most importantly, to understand physical principles filling them with electrons in atoms.
Based on the generality of the laws of Nature, rejecting the relativity and uncertainties of the microworld, we will accept the “hints” of the Sun:
.Ø the existence of certain orbits for electrons;
.Ø orbits must be quantized;
.Ø all orbits are circular or with slight eccentricity;
.Ø orbits are located mainly in one plane - in the equatorial plane of the nucleus.
The same features of the formation of the atomic structure directly follow from the laws of electrical and magnetic interaction nucleus and electrons in the SPIRIT environment.
The nucleus of an atom must attract electrons to itself by the force of electrical interaction. Electrical forces, as we found out (see 4.2), are determined by the rotational motion of the SPIRIT medium, “captured” by the rotation of the material masson - the electron. In the SPIRIT environment, the law of conservation of momentum operates: the movement of matter gives rise to the movement of the environment and vice versa. Therefore, the highest speed of movement of the SPIRIT medium interacting with the mason should manifest itself in its equatorial plane. We also found out that the unit charge of the proton and its spin are determined by the central “positron” in the central muon, and the remaining charges and spins of the muon and pi-mesons are compensated. In the nuclei of atoms, the charges of protons are summed up, which accordingly leads to an increase in the electric field strength - the force of attraction of electrons. Greatest forces the attraction of electrons by a proton and the nuclei of elements must act in their equatorial plane, the plane greatest effect vortex motion of the SPIRIT medium. This explains why filling shells in all layers n starts with circular orbits: 1s, 2s, 3s etc.
Orbits are determined electric field nuclei, and therefore must necessarily be circular, equatorial.
But why do orbits exist? Why does a proton, when it meets an electron, not attract it, and why does an electron, when moving in an electric field, not reach a positively charged proton or a nucleus with many protons? Why does the electron stop being attracted and remain in the Bohr orbit? This paradox - evidence of the impossibility of the formation of a hydrogen atom - is hushed up in physics.
According to the laws of electrostatics, the absence of attraction between positive and negative charges in the absence of a medium ( physical vacuum) or in the absence of its resistance (“ether”) is possible only in the absence of a charge on one of the particles or its change to the opposite one. Physics, which does not know what a charge is, cannot allow a change in charges, and therefore hushes up the problem. There is no such problem in the SPIRIT environment (see 3.2).
Let us consider the behavior of an electron during the formation of a hydrogen atom, using I. Dmitriev’s good model of the electron as a rotation of a spherical volume. Charge is a certain direction of rotation: right or left. Approaching the proton, the electron finds itself in the region of strong vortex motion of the SPIRIT medium, which is represented by vortex rotation at the speed of light. Electron in an electric field positive charge must speed up. But the motion of the surface points of the electron relative to the medium already corresponds to the speed of light and therefore cannot be accelerated. The electrical and magnetic constants of the SPIRIT environment will not “allow” this. Approaching the nucleus, the electron finds itself in the vortex motion of the medium, caused by the charge of the nucleus. In ch. Figure 4.4 shows that the size of the vortices in the SPIRIT medium is many times greater than the size of the vortices “captured” by the electron (Compton wavelength). Therefore, for the electron their effect will be chaotic. With such movement in the flow of the SPIRIT medium from the nucleus, the electron, which, according to our hypothesis, is the only mass elementary particle (see 3.2), can, during rotation, turn out to be either an “electron” or a “positron” in relation to the nucleus. The particle is subjected to either attractive or repulsive forces that tear it apart. The main condition for the existence of a particle - the unambiguous relationship between its volume and surface, determined by the value of Planck's constant - is violated.
As the only possible physical explanation possibility of the formation of atoms, one should accept the option according to which an electron, as a wave enclosed in a sphere, when deforming the surface under the influence of the vortex motion of the medium SPIRIT can form a wave enclosed in a torus. This is facilitated by magnetic moment electron, which is 658.21 times the magnetic moment of a proton. The process of interaction between the “cloud” of the SPIRIT environment around the electron and the “cloud” around the proton can be represented as the predominance magnetic field electron, which is considered as a directed movement of the SPIRIT medium above the magnetic field of the proton. Rotational movement vortices in the environment SPIRIT naturally turns into forward motion. This movement of the SPIRIT medium “carries” the electron along a circular orbit around the proton and “smears” it along the orbit. The forces of magnetic interaction at a certain distance from the nucleus, which is called the Bohr orbit, prevail over electrical force attraction. As the formulas below show, the characteristics of the SPIRIT medium in the Bohr orbit in the hydrogen atom are uniquely related to the characteristics of the electron, which can be represented on it as a wave torus (“electron bundle”), preserving mass and electrical characteristics electron.
The physical laws of electrical interaction prevent the formation of atoms. Only hypotheses about the only elementary particle“Mason = electron + positron” and the transformation of a particle in the orbit of an atom into a wave torus (“electron bundle”) are capable of explaining the birth of atoms.
The idea of an electron-mason as an organized movement of the SPIRIT environment and its interaction with the SPIRIT environment turns the paradox of dualism into a natural phenomenon occurring in the electromagnetic field of the nucleus.
In ordinary physical concepts, an electron “rotates” around the nucleus at a speed of more than 2000 km/s in an orbit with a length of 3.3·10 -10 m. Such movement, as well as theoretical probability orbitals, cannot correspond to the realities in Nature. The idea of transforming a mason into a wave torus resolves physical contradictions and explains when and why an electron particle turns into an electron wave.
Main hypothesis of this work about the unity of “SPIRIT + matter” leads to the conclusion that a free electron should be considered not as an independent substance, but as an organized movement of the SPIRIT medium, as a standing wave of oscillations of the medium in a spherical surface. This is a “standing” wave of oscillations, the continuous interaction of which with the SPIRIT medium gives rise to mass - a measure of inertia. These oscillations at the spherical interface cause response oscillations of the SPIRIT medium with its characteristics - electric and magnetic constants, which we interpret as movement at the speed of light. This is real oscillatory process. To explain the paradox of the birth of an atom, one only needs to “unfold” the spherical wave into a certain “cord” in orbit. In this case, our electron will be “smeared” in circular space in the equatorial plane of the nucleus. This analogue of an electric current in a ring wire - an “electron bundle” - represents a standing electromagnetic wave in a torus, located in space in the equatorial plane of the core, providing screening of its charge. Model electron orbitals unable to give such an explanation.
The transformation of the core of a “standing” wave, limited by a spherical surface, into a toroidal one in the electromagnetic field does not contradict physical laws. In Nature, the formation of ball lightning in a powerful electromagnetic field is possible, its existence, and its decay with the release of energy. The transformation of an electromagnetic wave, such as an electron, from a spherical shape to a torus shape in the vortex motion of the SPIRIT medium is a similar process of shape change electric charge. Evidence in favor of the hypothesis of the transformation of a spherical wave into a toroidal one can be the fact that this form of existence of an electron in an atom corresponds to the method of formation, shape and structure of an electromagnetic wave - quanta (see 4.4). It explains the stability of atoms, their structure and the processes of formation of radiation quanta during orbital transitions of electrons. Nature once again confirms the unity of the principles of system formation!
The torus-shaped model of the electron in orbit around the nucleus corresponds to natural principles formation of electromagnetic waves. The movement of an electron does not occur in an orbit, but this orbit is an electron-wave.
It's a wave oscillatory motion, caused by interaction with the environment, the SPIRIT is similar to an elementary circle alternating current very high frequency. The external rotation of the torus is characterized by the constants of the medium SPIRIT, and the energy corresponding to the rest mass of the electron modulates the wave of internal coaxial motion, which determines the radius of the orbit. In this case, the concept of orbit also requires changes, for example, “electronic harness”, “electric belt”. Ratings physical parameters“electronic harness” confirm its reality.
An electron captured by a proton must retain its mass, that is, the volume of the SPIRIT environment enclosed inside it. A “smeared” electron occupies a Bohr orbit in a hydrogen atom, the radius of which is determined by Planck’s constant, the (quadratic) charge of the electron, the electric and magnetic constants, and the “rest” mass of the electron:
a 0 = h 2 /(π ·μ 0 ·m e c 2 ·e 2) =ε 0 h 2 /(π m e 2)= 0.529177 10 -10 m.
Here a 0 - radius of Bohr's orbit, h- Planck's constant, m e - electron mass, c - speed of light , e - electron charge , μ 0 and ε 0 - magnetic and electrical constants of the environment SPIRIT.
The presence in the equation of the electrical and magnetic constants of the medium SPIRIT and the characteristics of the electron (quadratic charge and mass) is evidence of the natural interaction of “matter + SPIRIT” in the Bohr orbit and, accordingly, its uniqueness. Schrödinger's wave equations, which give correct results, and experiments on the scattering of photons on atoms, in accordance with which elastic scattering of waves occurs on bound electrons, and the mass of the electron corresponds to the Compton wavelength λ K:
λ K =h/ m e c = 2.426311·10 -12 m.
From known formulas quantum mechanics follows:
λ K = α· 2π·a 0 .
Here α = 1/137.036 is the fine structure constant.
Thus, the main orbit of an electron in a hydrogen atom is 137.036 ·λ k. The Compton wavelength, as shown (see 3.2), can be considered as the minimum possible “jump” of the electron and as the radius of the SPIRIT cloud around it.
Compton wavelength is the length of the electron wave in the orbit of an atom, physically determined by the fine structure constant of the part of the Bohr orbit.
By combining two the above formulas, we can understand the physical meaning of the fine structure constant:
1/α = 2π a 0m e c / h
Recalling that Planck's constant corresponds to the energy of one turn of the vortex in the structure of the Spirit (see 4.4), we determine that the reciprocal value of the fine structure constant is the ratio of the momentum of the electron in the first orbit around the proton to the momentum of the medium of the Spirit.
The ratio of the electron momentum in the first orbit around the proton to the energy of the minimum vortex in the SPIRIT medium (Planck's constant) is equal to the reciprocal of the fine structure constant. This is the law of conservation of momentum between the medium SPIRIT and the electron, in which the constant 1/α plays the role of a transfer coefficient, an analogue of the efficiency!
A justification for the size of the main electron orbit in the hydrogen atom was also obtained. Only on the circumference 2π a 0 the electron momentum is transferred to the SPIRIT medium and vice versa. There is their continuous interaction.
In contrast to the quantum mechanical concept of probability orbitals, the wave representation of an electron in a Bohr orbit is naturally determined by the size of the Compton wavelength - its minimum jump in the SPIRIT medium. These same representations make it possible to obtain all the parameters of the electron orbit in an atom. Considering a wave located in a Bohr orbit and limited by a surface with the radius of a torus, we can estimate it by equating the volumes of a torus and an electron-particle with a known radius of 4.536 · 10 -17 m.
Electron in Bohr orbit (a 0 = 0,529177· 10 -10 m) represents a torus-shaped wave - an “electron bundle” with a cross-sectional radius R e-tor = 1.9346 ·10 -20 m.
The transformation of a spherical particle nucleus into an “electron bundle” in the field leads to a sharp increase in the “matter + SPIRIT” interaction surface. Surface area of an electron particle S e-sphere= 2.5856 10 -32 m2, and the surface area of the “electronic bundle” S e-tor= 4.0417 ·10 -29 m2. The surface of continuous interaction with the SPIRIT environment increased by 1563 times. An increase in the surface area of the electron should indicate a sharp increase in the motion of the SPIRIT medium along the circumference of the electron torus. This movement is a magnetic field.
The magnetic moment of an electron particle is known: M e-sphere= 0.928477 10 -23 A m 2 (J/T).
Magnetic moment of an electron in orbit - M let's define it as circular current I, multiplied by the area of the circle S: M e-torus = I·S. Substituting I = q e·ν = q e· m e· c 2 / h And S= π a 0 2, let's define ν = 1.2356 10 20 s -1 ; I= 19.794 A. Magnetic moment of an electron in orbit M e-tor= 1.7413 10 -19 A m 2.
The value of the magnetic moment of the “electron bundle” is four orders of magnitude greater than that of the electron-particle, which indicates significant magnetic forces formed by electron orbits. Note that the orbitals quantum physics with the indefinite existence of the electron, they exclude the possibility of talking about magnetism in atoms and, therefore, are not able to explain why these orbitals and the atom itself are preserved.
The assessment performed cannot claim to be accurate magnetic flux in an atom due to uncertainty physical meaning the concepts themselves electricity and magnetic moment (see 4.2) and the possibility of applying the concept of current to one electron. However, from common understanding physical content of the magnetic field, as the directional movement of the SPIRIT medium, formed by interaction with the surface of the electron, a significant increase in the magnetic field of the “electron bundle” compared to the electron-particle becomes obvious.
Thus, an increase in the surface of an electron when it is included in an atom in the form of an “electron bundle” leads to the formation of a magnetic field of the electron in orbit - a directed and capable of indefinitely persisting flow of the SPIRIT medium; this thread is the one physical strength, which ensures the retention and existence of the electron-torus in the atomic orbit.
The analysis performed sufficiently explains the dualism of the electron. It is in the field of the nucleus that the electron is an electromagnetic wave, while free electrons are undoubtedly particles.
A counterweight mathematical models, in which the electron in the atom turns out to be undetectable inside the orbital clouds, the proposed model of an “electron bundle” with clear dimensions and coordinates is physically natural. Under the influence electromagnetic forces The electron particle, representing an ordered wave of the SPIRIT medium, in the field of the nucleus is forced to “stretch” throughout its entire orbit, turning into a torus wave, which is a material analogue of an electromagnetic wave. As shown (see 4.4), any electromagnetic wave, as a carrier of energy, is a torus-shaped formation propagating at the speed of light. Quite analogously, an electron in an atom must represent a torus-shaped wave motion with energy equivalent to the mass of the electron, fixed in an orbit around the nucleus. In this model, it is quite simple to explain the transition of an electron from an orbital high level into lower orbit with electromagnetic quantum radiation. A torus-shaped wave of large radius, when moving towards the nucleus, is compressed to the radius of the lower orbit, and during this movement sends into space a quantum torus corresponding to the energy of the difference between the energy levels of the atom.
Physical calculations can clarify the model of the transition of an electron-particle into a wave, but its essence should not change. Because such a hypothesis turns out to be logical and mathematical related properties mason (electron/positron) and the SPIRIT environment. The idea of a torus wave will allow us to explain the formation electronic shells atoms, and the structure of the shells will allow us to better understand Chemical properties elements as a result of the forces of magnetism.
We bring to your attention magazines published by the publishing house "Academy of Natural Sciences"
Kitaygorodsky A.I. Physics for everyone. Electrons. Edited by the Main Editorial Board of Physical and Mathematical Literature - M.: Nauka, 1979. - 208 p.Download(direct link) : fdvek3kn1979.djvu Previous 1 .. 13 > .. >> Next
So, it immediately becomes clear that atoms are mainly composed... of emptiness. Rare head-on collisions should be understood this way: inside the atom there is a positively charged nucleus. Electrons are located near the nucleus. They are very light and therefore do not pose a serious obstacle to the alpha particle. The electrons slow down the alpha particle, but each individual electron collision cannot deflect the particle from its path.
Rutherford admitted that the interaction forces between the similarly charged atomic nucleus and the alpha particle are Coulomb forces. Further assuming that the mass of an atom is concentrated at its nucleus, he calculated the probability of particles being deflected by specified angle and obtained a brilliant agreement between theory and experiment.
This is how physicists test the models they come up with.
Does the model predict the results of the experiment? - Yes. ,
So does it reflect reality?
Well, why so harshly? The model explains a number of phenomena, which means it is good. And its clarification is a matter for the future...
The results of Rutherford's experiments left no doubt about the validity of the following statement: electrons under the influence Coulomb forces move near the nucleus.
Some theories also followed from the theory. quantitative estimates, which were confirmed later. The dimensions of the smallest atomic nuclei turned out to be approximately 10""13 cm, while the dimensions of an atom were about 10-8 cm. ^
By comparing the experimental results with calculations, it turned out to be possible to estimate the charges of colliding nuclei. These assessments played a large, if not the main, role in the interpretation periodic law structure of elements.
So, the model of the atom has been built. But it immediately arises next question. Why don't electrons (negatively charged particles) fall onto the nucleus (positively charged)? Why is an atom stable?
What is incomprehensible here, the reader will say. After all, planets do not fall on the Sun.. Strength electrical origin is, like the force of gravity, a centripetal force and provides Roundabout Circulation electrons near the nucleus.
But the fact of the matter is that the analogy between planetary system and carries only an atom superficial character. As we will find out later, from the point of view general laws electromagnetic field an atom must emit electromagnetic waves. However, you may not know the theory of electromagnetism. Matter, i.e. atoms,
capable of emitting light and heat. If so, then the atom loses energy, which means the electron must fall onto the nucleus.
What is the way out? It is very “simple”: you need to come to terms with the facts and elevate these facts to the rank of a law of nature. This step was taken in 1913 by the great physicist of our century, Niels Bohr (1885-1962).
ENERGY QUANTIZATION
Like all first steps, this step was relatively timid. We will outline new law nature, which not only saved Rutherford’s atom, but also forced us to come to the conclusion that the mechanics of large bodies is inapplicable to particles of small mass.
Nature is structured in such a way that a number of mechanical quantities, such as angular momentum and energy, for any system of interacting particles cannot have continuous series values. On the contrary, the atom that we are talking about now, or the atomic nucleus, the structure of which we will talk about later, has its own sequence of energy levels, characteristic only of a given system. There is the lowest level (zero). The energy of the system cannot be less than this value. In the case of an atom, this means that there is a state in which the electron is at a certain minimum distance from the nucleus.
A change in the energy of an atom can only occur abruptly. If the jump occurred “up”, this means that the atom absorbed energy. If the jump occurred “down,” then the atom emitted energy.
We will see later how the emission spectra of various systems can be beautifully deciphered from these positions.
The formulated law is called the law of energy quantization. We can also say that energy has a quantum nature. ~
It should be noted that the law on quantization is completely general character. It applies not only to the atom, but to any object consisting of billions of atoms. But when dealing with big bodies, we can often “not notice” the quantization of energy.
The fact is that, roughly speaking, for an object consisting of a billion billion atoms, the number of energy levels increases by a billion billion times. The energy levels will be so close to each other that they will practically merge. Therefore, we will not notice the discreteness possible values energy. So the mechanics that we presented in the first book practically do not change when it comes to large bodies.
In the second book we found out that the transfer of energy from one body to another can occur in the form of work and in the form of heat. We are now in a position to explain the difference between these two forms of energy transfer. At mechanical impact(say when compressed) energy levels systems shift. This displacement is very insignificant and is detected only by subtle experiments and only if the pressures are high enough. As for thermal action, then it consists in converting the system from more low level energy to higher (heating) or from high to lower (cooling).