§1 charge and weight, nuclear cores

The most important characteristics of the kernel are its charge and mass M..

Z.- The charge of the nucleus is determined by the number of positive elementary charges focused in the kernel. Carrier of positive elementary charge r \u003d 1,6021 · 10 -19 CL in the kernel is a proton. The atom generally neutral and the nucleus charge determines the number of electrons in the atom. The distribution of electrons in the atom in the energy shells and subordrodes significantly depends on their total number in the atom. Therefore, the charge of the nucleus largely determines the distribution of electrons according to their states in the atom and the position of the element in the periodic Mendeleev system. The charge of the kernel is equalq. I = z.· e.where z.-Fig number of the kernel equal to the sequence number of the element in the Mendeleev system.

The mass of the atomic nucleus practically coincides with the mass of the atom, because the mass of electrons of all atoms, in addition to hydrogen, is approximately 2.5 · 10 -4 mass of atoms. The mass of atoms is expressed in atomic units of mass (A.M.). For A.Y.m. Adopted1 / 12 mass of carbon atom.

1 ae.m. \u003d 1,6605655 (86) · 10 -27 kg.

m. I = m A. - Z. m E.

Isotopes are called varieties of atoms of this chemical element, possessing the same charge, but differing in mass.

An integer closest to atomic mass expressed in A.E.m. . called a mass numberm I. denotes letter BUT. Chemical elenchation designation: BUT - mass number, x - symbol of the chemical element,Z.- Charging number - serial number in the Mendeleev table ():

Beryllium; Isotopes:, ".

Core radius:

where a is a mass number.

§2 The composition of the nucleus

Core atom of hydrogen called proton

m. Proton \u003d 1,00783 A.E.m. . .

Scheme of hydrogen atom

In 1932, a particle was discovered by a neutron, possessing Mas-Soy close to the mass of the proton (m. Neutron \u003d 1,00867 AE.M.) and not having an electric charge. Then D.D. Ivanenko formulated a hypothesis about the proton - neutron of the core structure: the core consists of protons and neutrons and their amount is equal to the mass number BUT. 3 trait numberZ. Determines the number of protons in the nucleus, the number of neutronsN. \u003d A - z.

Elementary particles - protons and neutrons incomingin the kernel, Received the common name of the nucleons. Nucleons nuclei are in states, essentially different from their free states. Between nucleons is speciali de R. interaction. It is said that the nucleon may be in two "charge states" - proton with charge+ e., I. Neu-throne with charge 0.

§3 Core communication energy. Weight defect. Nuclear power

Nuclear particles - protons and neutrons - are firmly held inside the nucleus, therefore, there are very large forces of attraction between them, it is possible to confront the vast repulsion forces between the same name of the proton. These special forces arising at low distances between nucleons are called nuclear forces. Nuclear forces are not electrostatic (Coulomb).

The study of the core showed that nuclear forces acting between nucleons possess the following features:

a) it is the forces short-range - manifested at distances of about 10 -15 m and sharply decreasing even with a slight increase in random;

b) Nuclear forces do not depend on whether there is a particle (nucleon) charge - in ordinary independence of nuclear forces. Nuclear forces acting between neutron and proton, between two neutrons, between the two protons are equal. Proton and neutron in relation to nuclear forces are the same.

Communication energy is a measure of the sustainability of the atomic nucleus. The binding energy of the nucleus is equal to the work that the nucleons should be made to split the nucleus on the co-set of its nucleons without a message of kinetic energy them.

M I.< Σ( m P. + m N.)

Me - the mass of the core

The mass metering of the core shows that the mass of the kernel is less than the sum of the rest of the components of its nucleons.

Value

serves the energy of communication and is called a mass defect.

Einstein equation in the special theory of relativity binds the energy and mass of the particles.

In general, the binding energy of the nucleus can be calculated by the formula

where Z. - charge number (number of protons in the kernel);

BUT - mass number (total number of nucleons in the kernel);

m P., , M N. and M I. - proton mass, neutron and nuclei

Mass defect (Δ m.) equal. and 1 AE. m. (A.E.M. - Atomic unit of mass) co-responsive communication energies (EC), equal to 1 A.E.E. (A.E.E. - atomic unit of energy) and equal to 1A.M. · C 2 \u003d 931 MeV.

§ 4 nuclear reactions

Nuclear changes when they interact with individual particles and with each other, it is customary called nuclear reactions.

The following nuclear reactions are distinguished.

1. Transformation reaction . In this case, the damned particle remains in the core, but the intermediate kernel eats any other particle, the poeto core is different from the target nucleus.

1. Radiation capture reaction . The damned particle is stuck in the core, but the excited core emits excessive energy, radiating γ-photon (used in the work of nuclear reactors)

An example of neutron capture reaction with cadmium

or phosphorus

1. Scattering. Intermediate kernel emits a particle identical

with riming, and maybe:

Elastic scattering carbon neutrons (used in reactors for slowing down neutrons):

Incomplete scattering :

1. Fission reaction. This is always the reaction with the release of energy. It is the basis for the technical preparation and use of nuclear energy. With the fission reaction, the excitation of the intermediate composite kernel is so large that it is divided into two, approximately equal fragments, with the depth of several neutrons.

If the excitation energy is small, then the separation of the nucleus does not occur, but the kernel, losing an excess of energy by emitting γ - photon or neutron, is rotated into normal state (Fig. 1). But if the neutron-contributed energia is large, the excited kernel begins to deform, it is formed a hauling and as a result it is divided into two fragments flying out with og-rod speeds, two neutrons are emitted.
(Fig. 2).

Chain reaction - self-developing fission reaction. For its implementation, it is necessary that from secondary neutrons formed with one act of division, at least one could cause the following act of division: (as some neutrons can participate in the capture reactions without causing a case). Quantitatively the condition of the existence of the chain reaction expresses reproduction coefficient

k. < 1 - цепная реакция невозможна, k. = 1 (m. = m. kr ) - chain reactions with a standing number of neutrons (in a nuclear reactor),k. > 1 (m. > m. kr ) - nuclear bombs.

RADIOACTIVITY

§1 Natural radioactivity

Radioactivity is a spontaneous transformation of unstable kernels of one element in the kernel of another element. Natural radioactivity It is called radioactivity, observed in the nature of unstable isotopes. Artificial radioactivity is called the radioactivity of isotopes obtained as a result of nuclear reactions.

Types of radioactivity:

1. α-decay.

The emission of the cores of some chemical elements of the α-system of two protons and two neutrons, connected together (A-particle - the kernel of the Ge-Lii atom)

α-decay inherent heavy nuclei with BUT\u003e 200 I.Z. \u003e 82. When moving in a means of α-particles, they produce in their way the strong ionization of atoms (ionization - separation of electrons from the atom), acting on them with its electric field. The distance that the α-particle flies in the substance to the fullest stop is called mileage of particles or penetrating ability (denotesR., [R] \u003d m, cm). . Under normal conditions α- particle formsin Air 30000 pairs of ions per 1 cm path. The specific ionization is called the number of pairs of ions formed by 1 cm mileage length. The particle has a strong biological effect.

The displacement rule for α-decay:

2. β-decay.

a) electronic (β -): the kernel emits an electron and electron antineutrino

b) positron (β +): the kernel emits the positron and neutrino

This processes occur by converting one type of nucleon in poison to another: neutron to proton or proton into neutron.

There are no electrons in the kernel, they are formed as a result of the mutual transmission of nucleons.

Positron - Particle, different from the electron, only sign in-row (+ e \u003d 1.6 · 10 -19 CL)

From the experiment it follows that with β - the decay of isotopes lose the same amount of energy. Consequently, on the basis of the law of conservation of Energy V. Pauli predicted that another light particle is thrown out, called antineutrino. Antineutrino does not have charge and mass. The loss of energy β - particles when passing them through the substance is caused by the main way, by ionization processes. Part of the energy is lost on X-ray radiation when braking β - particles by the cores of the absorbing substance. Since β - particles have a small mass, a single charge and very large speeds, their ionizing ability is small, (100 times less than that of α - particles), therefore, the penetrating ability (mileage) in β - particles is essentially more than in α - particles.

R β air \u003d 200 m, R β Pb ≈ 3 mm

β - - decay occurs in natural and artificial radioactive nuclei. β + - only with artificial radioactivity.

Displacement rule for β - - decay:

c) to - capture (electronic grip) - the kernel absorbs one of the electrons located on the shell to (lessL. or M.) of its atom, as a result of which one of the protons turns into a neutron, emitting neutrino

Scheme K - Capture:

The place E electron shell released by the captured electron is filled with electrons from the overlying layers, resulting in X-ray rays.

• γ rays.

Usually all types of radioactivity are accompanied by emitting γ rays. The γ rays are electromagnetic radiation, which has the wavelengths from one to the hundredths of the angstrom λ '\u003d ~ 1-0.01 Å \u003d 10 -10 -10 -12 m. The energy of γ rays reaches millions of eV.

W Γ ~ MEB

1EV \u003d 1.6 · 10 -19 J

The kernel, experiencing a radioactive decay, is usually excited, its transition to the ground state is accompanied by the emitting γ - photon. In this case, the energy of the γ-photone is determined by the condition

where e 2 and E 1 nucleus.

E 2 - Energy in an excited state;

E 1 - the energy is basically condition.

The absorption of the γ rays of the substance is due to the three main processes:

• photo effects (as hV < l MэB);
• education of steam electron - positron;

or

• scattering (Compton Effect) -

The absorption of γ rays occurs under the law of the buger:

where the μ is a loose attenuation coefficient, depending on the energy of γ - rays and the properties of the medium;

І 0 - the intensity of the incident parallel beam;

I. - the intensity of the beam after the passage of the substance thick h. cm.

γ-rays are one of the most penetrating emissions. For the most alert ray (hν Max) The thickness of the half absorption layer is equal to the lead 1.6 cm, in the gland - 2.4 cm, in aluminum - 12 cm, in the ground - 15 cm.

§2 The basic law of radioactive decay.

The number of broken kernelsdN. in proportion to the initial number of cores N. and time decaydt., dN.~ N. dt.. The main law of radioactive decay in differential form:

The coefficient λ is called a constant decay for this type of nuclei. Sign "-" means thatdN. It must be negative, since the final number of non-nuclear nuclei is less than the initial.

consequently, λ characterizes the proportion of nuclei that falling over the unit of time - neu. Determines the speed of radioactive decay. λ does not depend on external conditions, but is determined only by the internal properties of the nuclei. [λ] \u003d s -1.

The main law of radioactive decay in integrated form

where N. 0 - the initial number of radioactive nuclei att.=0;

N. - the number of not broken nuclei at the time of timet.;

λ is a constant radioactive decay.

The rate of decay in practice is judged using not λ, and T 1/2 - the period of the luraspade - the time for which half of the initial number of nuclei decays. Communication t 1/2 and λ

T 1/2 U 238 \u003d 4.5 · 10 6 years, T 1/2 Ra \u003d 1590 years, T 1/2 Rn \u003d 3,825 days. The number of decays per unit of time A \u003d -dN./ dt.it is called the activity of this radioactive substance.

Of

follow

[A] \u003d 1 bakel \u003d 1Aspad / 1C;

[A] \u003d 1ki \u003d 1Kuri \u003d 3.7 · 10 10 BC.

Law Change Activity

where a 0 \u003d λ N. 0 - initial activity at timet.= 0;

A - activity at timet..

Academician A. F. Ioffe. "Science and Life" № 1, 1934

The article "The Nucleus of Atom" Academician Abram Fedorovich Ioffe opened the first issue of the magazine "Science and Life", newly created in 1934.

E. Rootford.

F. U. Aston.

Wave nature of matter

At the beginning of the 20th century, the atomistic structure of matter ceased to be a hypothesis, and the atom became the same reality as real facts and phenomena are real for the NAC.

It turned out that the atom is a very complex education, which undoubtedly includes electrical charges, and maybe only some electrical charges. From here, naturally, there was a question about the structure of the atom.

The first model of the atom was built according to the sample of the solar system. However, such an idea of \u200b\u200bthe structure of the atom was soon insolvent. And it is natural. The idea of \u200b\u200batom as a solar system was a purely mechanical transfer of a picture associated with astronomical scale into an atom region, where the scale is only the stomillional shares of the centimeter. Such a sharp quantitative change could not be entrusted with a very significant change in the quality properties of the same phenomena. This difference was primarily affected by the atom, in contrast to the solar system, should be built in much more stringent rules than those laws that define the orbits of the planets of the solar system.

There were two difficulties. First, all atoms of this kind, this element in their physical properties are exactly the same, and therefore, the orbits of electrons in these atoms should be completely the same. Meanwhile, the laws of mechanics, controlling the movement of the celestial bodies, do not give a resolutely no reason. Depending on the initial rate of orbit, the planet may be, according to these laws, is completely arbitrary, the planet can rotate each time with the corresponding speed on any orbit, at any distance from the Sun. If the same arbitrary orbits existed in atoms, then the atoms of the same substance could not be so coinciding according to their properties, for example, to give a strictly equal range of the glow. This is one contradiction.

Other - it was that the movement of an electron around the atomic nucleus, if the laws are used to apply, we are well-studied on a large scale of laboratory experiments or even astronomical phenomena, should be accompanied by continuous energy emission. Consequently, the atomic energy should have been continuously exhausted, and again the atom could not keep the same and unchanging their properties over the centuries and millennia, and all the world and all atoms would have to experience continuous attenuation, the continuous loss of energy consisting in them. This is also incompatible with the basic properties of atoms.

The last difficulty was felt particularly acute. It seemed that it started all the science into an unresolved deadlock.

Lorenz's largest physicist finished our conversation about this: "I regret that I didn't die five years ago, when this contradiction was not yet. Then I would have a conviction that I revealed a part of the truth in the phenomena of nature."

At the same time, in the spring of 1924, de Broglie, a young student of Lanzhene, in his dissertation expressed a thought, which in his further development led to a new synthesis.

The idea of \u200b\u200bde broille, then rather substantially modified, but still basically preserved, was that the movement of an electron rotating around the core in the atom, there is simply the movement of a certain ball, as they imagined earlier that this movement is accompanied by some A wave coming together with a moving electron. The electron is not a ball, but some blurred electrical substance in space, the movement of which is at the same time the spread of the wave.

This representation, then widespread not only on electrons, but also on the movement of all body - and the electron, and the atom, and the whole totality of atoms, says that any movement of the body concludes two parties in itself, from which we can see especially distinct one side, while the other is not noticeable. In one case, we see as if the propagating waves and do not notice the movement of particles, in another case, on the contrary, the moving particles themselves are to the fore, and the wave eludes our observation.

But in fact, both of these parties are always available, and, in particular, in the movement of electrons there is not only the movement of the charges themselves, but also the spread of the wave.

It cannot be said that the movements of electrons in orbit are not, and there is only pulsation, only waves, i.e. something else. No, it would be more correct to say so: the movement of the electrodes, which we likened the movement of the planets around the Sun, we do not deny at all, but the most this movement has the nature of the ripple, and not the nature of the movement of the globe around the sun.

I will not put here to state the structure of the atom, the structure of the electronic shell, which determines all the basic physical properties - grip, elasticity, capillary, chemical properties, etc. All this is the result of the movement of the electronic shell, or, as we say, ripples Atom.

The problem of the atomic nucleus

The kernel plays the most significant role in the atom. This is the center around which all electrons rotate and the properties of which ultimately determines everything else.

The first thing we could learn about the kernel is his charge. We know that the atom includes a number of negatively charged electrons, but the atom as a whole does not have an electric charge. So, somewhere there must be appropriate positive charges. These positive charges are concentrated in the core. The kernel is a positively charged particle, around which the electronic atmosphere surrounds the core. The charge of the nucleus determines the number of electrons.

Electrons of iron and copper, glass and wood are completely the same. For an atom, no misfortune is not to lose several of its electrons or even lose all its electrons. While there is a positively charged kernel, this core will attract so many electrons from other surrounding bodies as he needs, and the atom will continue. The iron atom must remain iron until it is for its core. If it loses several electrons, the positive charge of the nucleus will be larger than the totality of the remaining negative charges, and the entire atom as a whole will acquire an excess positive charge. Then we call it not at an atom, but a positive iron ion. In another case, the atom may, on the contrary, bring more negative electrons to itself than there are positive charges, - then it will be charged negatively, and we call it a negative ion; It will be a negative ion of the same element. Consequently, the individuality of the element, all its properties exist and are determined by the core, the charge of this kernel is primarily.

Further, the mass of the atom in the overwhelming part is determined by the core, and not the electron, the mass of the electrons is less than one thousandth mass of the total atom; More than 0.9999 of the whole mass is the mass of the kernel. It has the greatest importance that we consider the measure of the energy of the energy that this substance has a measure; Mass - the same measure of energy as Erg, kilowatt-hour or calorie.

The complexity of the nucleus was discovered in the phenomenon of radioactivity, open, soon behind the X-rays, on the verge of our century. It is known that radioactive elements continuously emit energy in the form of alpha, beta and gamma rays. But such continuous energy radiation must have some source. In 1902, Rutherford showed that an atom should be the only source of this energy, otherwise to say nuclear energy. The other side of radioactivity lies in the fact that the emission of these rays translates one element in one place of the periodic system, in another element with other chemical properties. In other words, radioactive processes transform elements. If it is true that the nucleus of the atom is determined by its individuality and that, while the core is intended, until then, the atom remains the atom of this element, and not any other, then the transition of one element to another means the change in the nucleus of the atom.

Rays thrown by radioactive substances give the first approach, allowing themselves to be some general idea of \u200b\u200bwhat is concluded in the kernel.

Alpha rays are helium kernels, and helium is a second element of the periodic system. It can be thought therefore that the kernel includes the helium nuclei. But the measurement of the velocities with which the alpha rays take out, leads to a very serious difficulty.

Theory of radioactivity Gamova

The kernel is charged positively. When approaching it, any charged particle is experiencing an attraction or repulsion. In a large scale of laboratories, the interaction of electrical charges are determined by the law of the coulon: two charges interact with each other with force, inversely in a proportional square of the distance between them and directly proportional to one and other charges. Studying the laws of attraction or repulsion that particles experience, approaching the kernel, Rutherford found that up to very close to the nucleus of distances, about 10 -12 cm, even the same law of Coulomb. If so, then we can easily calculate what work should make the kernel, repulse a positive charge when it comes out of the kernel and is thrown out. Alpha particles and charged helium kernels, flying out of the kernel, are moving under the repellent effect of his charge; And now the corresponding calculation gives that under the action of alpha-particle repulsion only, the kinetic energy corresponding to at least 10 or 20 million electro-rolled, i.e., the energy that is obtained during the passage, equal to the charge of the electron, Potential differences of 20 million volts. And in fact, flying out of the atom, they go out with the energy, much less, in just 1-5 million e-control. But, in addition,

naturally, it was expected that the kernel, throwing away the alpha particle, still gives her in addition. At the time of throwing, something like an explosion occurs in the kernel, and the most important explosion reports some kind of energy; The work of the repulsion forces is added to this, and it turns out that the sum of these energies is less than what one repulsion should give. This contradiction is removed as soon as we abandon the mechanical transfer to this area of \u200b\u200bviews developed on the experience of learning large bodies, where we do not take into account the wave nature of the movement. G. Gamov first gave the correct interpretation of this contradiction and created the wave theory of the nucleus and radioactive processes.

It is known that at sufficiently large distances (more than 10 -12 cm) the kernel pushes a positive charge from itself. On the other hand, it is undoubtedly inside the kernel itself, in which there are many positive charges, for some reason they are not repelled. The very existence of the kernel shows that positive charges inside the core mutually attract each other, and outside the nucleus - it is repelled from it.

How can I describe the energy conditions in the core itself and around it? Gamov created the following performance. We will depict the diagram (Fig. 5) the value of the energy of a positive charge in this place the distance from the horizontal direct BUT.

As the energy charge approaches the kernel will increase, because work will be performed against the power of repulsion. Inside the nucleus, on the contrary, the energy must decrease again, because there is no mutual repulsion, but mutual attraction. At the borders of the nuclei there is a sharp discontinuation of the energy of the energy. Our drawing is depicted on the plane; In fact, it is necessary, of course, to imagine it in space with the same distribution of energy and in all other directions. Then we get that around the kernel there is a spherical layer with high energy, as if some energy barrier protecting the kernel from the penetration of positive charges, the so-called "Barrier Gamova".

If you stand on the point of view of the usual views on the movement of the body and forget about the wave nature, it is necessary to expect that only such a positive charge, the energy of which is not less than the height of the barrier can be accessed into the kernel. On the contrary, in order to exit the kernel, the charge must first reach the vertices of the barrier, after which its kinetic energy will begin to increase as it removes from the nucleus. If the energy was zero at the top of the barrier, then when removing from the atom, it will receive the same 20 million electron-roll, which are in fact never observed. A new understanding of the kernel, which was introduced by Gam, is as follows. The movement of the particle should be considered as a wave. Consequently, on this movement the energy is affected not only in the point occupied by a particle, but also in the entire blurred wave of a particle covering a rather significant space. Based on the representations of the wave mechanics, we can argue that if even the energy at this point did not reach the limit that corresponds to the top of the barrier, the particle may be on the other side, where it is no longer drawn into the core of the attraction force there.

Something similar represents the next experience. Imagine that the wall of the room is a barrel with water. From this barrel, a pipe was conducted, which passes high upstairs through the hole, in the wall and serves water; Below the water is poured. This is a well-known device called a siphon. If the barrel on the other side is set up higher than the end of the pipe, then water will continuously flow through the speed determined by the difference in the water level in the barrel and the end of the pipe. There is nothing surprising here. But if you did not know about the existence of a barrel on the other side of the wall and saw only the pipe on which water flows from a high height, then for you this fact would seem implacable contradiction. Water flows from a high height and at the same time does not accumulate that energy that corresponds to the height of the pipe. However, the explanation in this case is obvious.

We have a similar phenomenon in the kernel. Charge from its normal position BUT rises to the state of greater energy INbut not at all reaches the vertices of the barrier FROM (Fig. 6).

From state IN Alpha particle, passing through the barrier, begins to repel from the kernel not from the top FROM, and with a smaller energy height B 1.. Therefore, when you exit the outside, the energy accumulated by a particle will depend on the height FROM, and from a smaller height equal B 1. (Fig. 7).

This qualitative reasoning can be covered in a quantitative form and give a law, which determines the probability of passing the alpha particle barrier depending on the energy INwhich it has in the kernel, and therefore, from the energy that it will receive when leaving the atom.

Using a number of experiments, a very simple law was established, which binds the numbers of alpha particles ejected by radioactive substances with their energy or speed. But the meaning of this law was completely incomprehensible.

The first success of Gamova was that from his theory, this quantitative law of the emission of alpha particles was completely eliminated. Now the "energy barrier Gamova" and his wave interpretation are the basis of all our ideas about the kernel.

The properties of alpha-rays are qualitative and quantitatively explained by the theory of Gamov, but it is known that radioactive substances are emitted and beta-rays are the flows of fast electrons. Electron emitting model is not able to explain. This is one of the most serious contradictions of the theory of the atomic nucleus, which until the very last time remained unresolved, but the solution of which is now apparently scheduled.

The structure of the nucleus

We now turn to the consideration of what we know about the structure of the kernel.

More than 100 years ago, the thought was made that, perhaps, elements of the periodic system are not at all separate, unnecessary non-associated forms of matter, but are only different combinations of hydrogen atom. If it were so, it would be possible to expect that not only the charges of all the nuclei will represent the whole multiple charge of hydrogen, but also the masses of all nuclei will be expressed as many as the mass of the hydrogen core, i.e. all atomic weights would have to be expressed whole numbers. And indeed, if you look at the table of atomic scales, you can see a large number of integers. For example, carbon - exactly 12, nitrogen is exactly 14, oxygen - exactly 16, fluorine - exactly 19. This is, of course, not an accident. But there are still atomic weights, far from integers. For example, neon has atomic weight 20.2, chlorine - 35.46. Therefore, the hypothesis of the subject remained partial guessed and could not be done by the theory of the structure of the atom. Studying the behavior of charged ions, it is especially easy to study the properties of an atom nucleus, affecting them, for example, an electric and magnetic field.

The method-based method, brought to the extremely high accuracy of Aston, made it possible to establish that all elements whose atomic weights were not expressed in integers, in fact, are not a homogeneous substance, but a mixture of two or several - 3, 4, 9 - different species Atoms. For example, the atomic weight of chlorine, equal to 35.46, is explained by the fact that there are actually several varieties of chlorine atoms. There are chlorine atoms with atomic weight 35 and 37, and these two types of chlorine are mixed between themselves in such a proportion that their average atomic weight is obtained 35.46. It turned out that not only in one particular case, but in all cases without exception, where atomic weights are not expressed by integers, we have a mixture of isotopes, i.e. atoms with the same charge, therefore, representing the same element but with different masses. Each single variety of atoms always has a whole atomic weight.

Thus, the hypothesis of the assumption received a significant reinforcement immediately, and the question could be considered solved if it were not for one exception, namely, hydrogen itself. The fact is that our atomic scale system is constructed not on hydrogen adopted per unit, but on atomic oxygen weight, which is conditionally adopted equal to 16. With respect to this weight, atomic weights are expressed almost accurate integers. But the hydrogen itself in this system has atomic weight not one, but a bit more, it is 1,0078. This number differs from a unit rather significantly 3/4%, which far exceeds all possible errors in the definition of atomic weight.

It turned out that both oxygen has 3 isotopes: besides the predominant, with atomic weight 16, the other - with atomic weight 17 and the third - with atomic weight 18. If you attract all atomic weights to isotope 16, then the atomic weight of hydrogen will still be a little more unit. Next, the second isotope of hydrogen was found - hydrogen with atomic weight 2 - deuterium, as his Americans discovered, or diplogne, as the British called him. This deuterium is noticed only about 1/6000 part, and therefore at the atomic weight of hydrogen the presence of this impurity affects very little.

The following helium hydrogen has atomic weight 4.002. If it were composed of 4 hydrogen, then the atomic weight should be obviously 4.031. Consequently, in this case, we have some atomic weight loss, namely: 4.031 - 4.002 \u003d 0.029. Is it possible? While we did not consider a lot of some measure of matter, of course, it was impossible: it would mean that part of the matter disappeared.

But the theory of relativity established with a certainty that the mass is not a measure of the number of matter, and the measure of that energy that this matter has. Matter is measured not in mass, but the number of charges constituting this matter. These charges may have greater or less energy. When the same charges come closer - the energy increases when they are removed - the energy decreases. But this, of course, does not mean that matter has changed.

When we say that in the formation of helium from 4 hydrogens, 0.029 atomic weight disappeared, this means that the energy corresponding to this magnitude disappeared. We know that each gram of matter has an energy equal to 9. 10 20 ERG. When forming 4 g of helium, energy is lost equal to 0.029. nine . 10 20 Ergam. Due to this reduction in energy, 4 hydrogen cores will be connected to a new kernel. Excessive energy is separated into the surrounding space, and there will be a compound with slightly lower energy and mass. Thus, if atomic weights are measured not exactly, integers 4 or 1, a 4.002 and 1.0078, then these thousandths are particularly particularly important, because they determine the energy that is emitted during the formation of the kernel.

The more energy is released during the formation of the nucleus, i.e., the larger the loss of atomic weight, the stronger the core. In particular, the helium core is very firmly, because when it is formed, the energy corresponding to the loss in atomic weight is released - 0.029. This is a very big energy. To judge her, it is best to remember such a simple ratio: one thousandth atomic weight corresponds to about 1 million electron. So 0.029 is about 29 million electronic content. In order to destroy the helium core to decompose it back to 4 hydrogen, we need a colossal energy. The core does not receive such energy, therefore the helium core is extremely stable, and therefore it is precisely from radioactive nuclei that a hydrogen nucleus is distinguished, but the whole kernel of helium, alpha particles. These considerations lead us to a new estimate of atomic energy. We already know that almost all the energy of the atom is concentrated in the kernel, and with a huge energy. 1 g of substances have, if we translate to a more visual language, so much energy as possible from burning 10 trains of 100 oil wagons. Consequently, the kernel is a completely exceptional source of energy. Compare 1 g with 10 trains - such a ratio of energy concentration in the kernel compared with the energy we use in our technology.

However, if you think about the facts that we now consider, you can, on the contrary, come to the exact opposite look at the core. The kernel from this point of view is not a source of energy, but its cemetery: the kernel is a residue after the extraction of a huge amount of energy, and in it we have the lowest state of energy.

Therefore, if we can talk about the possibility of using the energy of the nucleus, then only in the sense that, maybe not all the kernels reached extremely low energy: after all, hydrogen and helium are both in nature, and therefore not all hydrogen Connected to helium, although helium and has less energy. If we could have existing hydrogen to rally in helium, we would get a known amount of energy. These are not 10 trains with oil, but still it will be about 10 wagons with oil. And this is not so bad if it was possible from 1 g of substance to get so much energy as from burning 10 oil cars.

These are possible energy reserves when rebuilding nuclei. But the possibility, of course, is still far from reality.

How can these opportunities be implemented? In order to evaluate them, we turn to the consideration of the composition of the atomic nucleus.

We can now say that in all kernels there are positive hydrogen cores, which are called protons, have an atomic weight unit (more precisely 1.0078) and a single positive charge. But the kernel cannot consist of some protons. Take, for example, the hardest element that occupies the 92nd place in the periodic table - uranium with atomic weight 238. If we assume that all these 238 units are composed of protons, then the uranium would have 238 charges, meanwhile it has only 92. Consequently, either there are not all particles charged, or there are 146 negative electrons except 238 protons. Then everything is safe: atomic weight would be 238, positive charges 238 and negative 146, therefore, total charge 92. But we have already found that the assumption of the presence in the kernel of electrons is incompatible with our ideas: neither size nor magnetic properties of electrons in The kernel cannot be placed. There was some kind of contradiction.

Opening neutron

This contradiction was destroyed by a new experienced fact that Irena Curie was opened about two years ago and her husband Zolio (Irena Curie - the daughter of Mary Curie, who opened radium). Irena Curie and Zolio discovered that during the bombardment of beryllium (the fourth element of the periodic system), beryllium alpha particles emit some strange rays penetrating through the huge strata of the substance. It would seem that they are so easily penetrated through substances, they should not cause any significant actions there, otherwise their energy would have exhausted and they would not penetrate through the substance. On the other hand, it turns out that these rays, encountered with the kernel of some atom, discard it with a huge force, as if a severe particle bending. So, on the one hand, you need to think that these rays are heavy nuclei, and on the other hand, they are able to pass huge stratas, without affecting any influence.

The resolution of this contradiction was found in that this particle was not charged. If the particle does not have an electric charge, then nothing will act on it, and she herself will not act. Only when she jumps out with her move somewhere on the kernel, she throws him.

Thus, new uncharged particles appeared - neutrons. It turned out that the mass of this particle is about the same as the mass of hydrogen particles - 1.0065 (one thousandth less than the proton, it became, the energy of it is about 1 million electroolt less). This particle is similar to the proton, but only deprived of a positive charge, she is neutral, she was called neutron.

As soon as the existence of neutrons turned out, a completely different idea of \u200b\u200bthe structure of the kernel was proposed. It was first expressed by D. D. Ivanenko, and then developed, especially by Gayisenberg, who received the Nobel Prize last year. In the core can be protons and neutrons. It was possible to assume that the kernel was made only from protons and neutrons. Then everything is different, but quite simply seems to be all the construction of the periodic system. How, for example, you need to imagine uranium? Its atomic weight 238, i.e. there are 238 particles. But some of them are protons, some neutrons. Each proton has a positive charge, neutrons do not have a charge at all. If the charge of uranium is 92, then this means that 92 is a proton, and everything else is neutrons. This idea has already led to a number of quite wonderful success, immediately explained the whole range of properties of the periodic system, which were previously presented at all mysterious. When protons and neutrons are a bit, then, according to modern ideas of wave mechanics, it is necessary to expect that the number of protons and neutrons in the core is equally. Only Proton has a charge, and the proton number gives a nuclear number. And the atomic weight of the element is the sum of the scales of protons and neutrons, because both are at the unit of atomic weight. On this basis, it can be said that the atomic number is half of the atomic weight.

Now it still remains one difficulty, one contradiction. This is a contradiction created by beta particles.

Opening of Positron

We came to the conclusion that there is nothing in the core except a positively charged proton. But how then are the negative electrons ejected from the kernel, if there are no negative charges there? As you can see, we fell into a difficult position.

From it, we will again withdraw a new experimental fact, a new discovery. This discovery was done, perhaps for the first time, D. V. Skobeelsyn, who, long ago, after studying the cosmic rays, found that among charges that emit cosmic rays, there are also positive light particles. But this discovery was so contrary to the fact that it was firmly established that Skobelsyn first did not give his observations of such an interpretation.

The next one who discovered this phenomenon was American Andersen's American Physicist in Pasaden (California), and after him in England, in the laboratory of Rutherford, - Blackket. It is positive electrons or, as they were not very successful - positrons. What really is positive electrons - it is possible to easily see on their behavior in a magnetic field. In a magnetic field, the electrons are deflected in one direction, and the positrons to another, and the direction of their deviation determines their sign.

Initially, positrons were observed only when the cosmic rays passes. Most recently, the same Irena Curie and Jolio opened a new wonderful phenomenon. It turned out that there is a new type of radioactivity that the nuclei of aluminum, boron, magnesium, they themselves are not radioactive, being bombarded by alpha-rays, become radioactive. Within 2 to 14 minutes, they continue to emit particles themselves, and these particles are no longer alpha and beta rays, but positrons.

The theory of positrons was created much earlier than the positron itself was found. Dirac set itself the problem to give the equations of wave mechanics such a form so that they satisfy the theory of relativity.

These Dirac equations, however, led to a very strange consequence. The mass in them is symmetrically, i.e., when the mass change changes, the opposite equation does not change. This symmetry of equations relative to the mass allowed Dirak to predict the possibility of the existence of positive electrons.

At that time, no one has observed positive electrons, and there was a solid confidence that there are no positive electrons (it can be judged by the caution that came to this issue and Skobeltsyn and Andersen), so Dirac theory was rejected. Two years later, positive electrons were actually found, and naturally remembered the theory of Dirac, which predicted their appearance.

"Materialization" and "annihilation"

This theory is associated with a number of unjust interpretations that turn it out from all sides. I would like to disassemble here so on the initiative of Madame Curie the process of materialization - the appearance of a pair of a positive and negative electron when passing the gamma rays. This experienced fact is interpreted as the conversion of electromagnetic energy into two particles of matter, which previously did not exist. This fact, therefore, is interpreted as the creation and disappearance of matter under the influence of those other rays.

But if you look closer to the fact that we actually observe, it is easy to see that such an interpretation of pair appearance has no reason. In particular, in the work of Skobeltsyna, it is perfectly clear that the appearance of a pair of charges under the influence of gamma rays occurs at all in the empty space, the appearance of steam is always observed only in atoms. Consequently, here we are dealing not with the materialization of energy, not with the advent of some kind of new matter, but only with the division of charges within the matter that already exists in the atom. Where was she? It should be thought that the process of splitting a positive and negative charge occurs not far from the nucleus, inside the atom, but not inside the nucleus (at a relatively not very long distance of 10 -10 -10 -11 cm, while the radius of the kernel 10 -12 -10 -13 cm ).

Absolutely, it can also be said about the reverse process of "annihilation of matter" - compounds of a negative and positive electron with the release of one million electron electron automation in the form of two quanta of electromagnetic gamma rays. And this process is always occurring in the atom, apparently close to its kernel.

Here we approach the possibility of permission of the contradictions noted by us, to which the emitting of beta rays of negative electrons with a core, which, as we think, does not contain electrons.

Obviously, beta particles are not flying out of the nucleus, but thanks to the kernel; Due to the release of energy inside the core, there is a process of splitting on a positive and negative charges, and the negative charge is ejected, and the positive retracts into the kernel and binds to the neutron, forming a positive proton. This is the assumption that has been expressed lately.

That's what we know about the composition of the atomic nucleus.

Conclusion

In conclusion, let's say a few words about further prospects.

If, when studying atoms, we reached some borders, followed by quantitative changes to new qualitative properties, then the laws of wave mechanics that we found in a nuclear shell are stopped at the borders of the atomic nucleus; In the kernel, there is very much unclear contours of a new, even more generalizing theory, with respect to which the wave mechanic is only one side of the phenomenon, the other side of which begins to open now - and begins, as always, with contradictions.

Works on the atomic core have another very curious side, closely twisting the utensils with the development of technology. The kernel is very well protected by the Barrier of Gamov from external influences. If, not limited to the observation of the disintegration of the nuclei in radioactive processes, we would like to leave the kernel from the outside, rebuild it, then it would take extraordinary but powerful impact.

The task of the nucleus most in an instructive way requires the further development of technology, the transition from those stresses that have already been mastered by high-voltage techniques, from voltages of several hundred thousand volts, to millions of volts. A new stage is created and in the technique. This work on the creation of new voltage sources, millions of volts, is now being conducted in all countries - and abroad and we, in particular in the Kharkov laboratory, which is the first to start this work, and in the Leningrad Physico-Technical Institute, and in other places.

The problem of the nucleus is one of the most relevant problems of our time in physics; Over it is necessary with emergency intensity and perseverance to work, and in this work it is necessary to possess a great courage of thought. In my presentation, I pointed out several cases when, moving to a new scale, we were convinced that our logical habits, all our ideas built on limited experience, are not suitable for new phenomena and new scales. It is necessary to overcome this conservatism of common sense to each of us. Common sense is a concentrated experience of the past; It is impossible to expect that this experience fully covers the future. In the nucleus region, more than any other, it is necessary to keep in mind the possibility of new quality properties and not be afraid of them. It seems to me that it is here that the power of the dialectical method should be affected, deprived of this conservatism of the method predicted and the entire course of the development of modern physics. Of course, I understand here under the dialectical method, not a totality of phrases taken from Engels. Not his words, but their meaning should be transferred to our work; Only one dialectical method can promote us forward in such a completely new and advanced area as the kernel problem.

Composition and characteristics of the atomic nucleus

Atom - The smallest part of the chemical element capable of independent existence and is the carrier of its properties. Atom is an electrically neutral system consisting of a positively charged nucleus and negatively charged electrons. The diameter of the atom of about 10 -10 m, the kernel diameter - 10-15 - 10-14 m. The atomic core has a complex structure. In 1932, V.Gaisenberg and D.Ivantenko proposed the nucleon model of the structure of the core, according to which the core of the atom consists of protons and neutrons.

Proton[from Greek. protos.- the first] (symbol) is a stable elementary particle, the core of the hydrogen atom. Proton's lifetime\u003e 10 31 years old. Weight 1,6726 ∙ 10 -27 kg 938.3 MeV. Electric proton charge Positive: 1.6 ∙ 10 -19 CL. The spin of the proton is equal to ½, so it obeys the statistics of Fermi Dirak. The number of protons in the kernel is the charge number, determines the shared charge of the core and the sequence number of the element in the Mendeleev table. The nucleus charge will determine the number of electrons in the atom, the configuration of their electronic shells, the size and nature of the intra-large electric field. The number of electrons in the neutral atom is equal to the number of protons in the nucleus, and their overall negative charge is equal.

Proton characteristics, neutron, electron
Characteristic	Proton	Neutron	Electron
Mass, MeV	938.28	939.57	0.511
Electric charge (in electron charge units)	+1		-1
The internal moment of the amount of movement (in units ћ)	1/2	1/2	1/2
Parity	+1	+1	+1
Statistics	Fermi Dirac.
Magnetic moment (in units of nuclear magneton)
+2.79	-1.91
(in units of magneton boron)			1.001
Lifetime	\u003e 10 25 years	887+ 2 S.	\u003e 4.3 · 10 23 years
Type of decay		PE - ν E

Neutron(symbol n.) [from Lat neuter- None, nor the other] - an elementary particle with a zero electrical charge, a peace of rest 1.6749 ∙ 10 -27 kg (939,565 MeV). Along with the proton under the general name nuclon It is part of atomic nuclei. It has spin ½, reports Fermi Dirac statistics (is fermion). Opened in 1932 by J. Chadwik. In the free state of neutron is unstable, spontaneously disintegrates, turning into a proton with emission of the electron and antineutrino: Neutron life - 896 p.

Proton and neutron are considered to be two states of nucleon. The mass of the atom is determined mainly by the mass of its kernel. The mass number depends on the total number of protons and neutrons in the nucleus: (The kernel contains protons and neutrons). The mass of the atom nucleus is expressed in atomic units of mass. Atomic unit of mass (A.E.M.) is a mass unit equal to 1/12 carbon isotope mass; It is used in atomic and nuclear physics to express masses of elementary particles, atoms, molecules. 1 A.E.M. \u003d 1,6605655 · 10 -27 kg.

To denote the nuclei of atoms adopted symbolism

where - the symbol of the chemical element, is the charge number, the mass number.

Isotopes They call the kernels having the same charge, but various mass numbers (i.e. differ in the number of neutrons). For example,

Nuclei with the same but different are called fromobami. For example,

Kernels with the same number of neutrons, but different numbers of protons are called isotones.For example,

Kernels with the same number of protons and neutrons, but different periods of the half-life are called isoma.For example, there are two types of bromine cores with half-life of 4.4 hours and 18 minutes.

Currently, more than 2,300 cores are known, about 300 of them are stable, the rest are unstable. In nature, it is elements with atomic numbers from 1 to 92 (except for technetium and a \u003e\u003e). Elements with 93 are obtained artificially called transuranov.

The figure shows the N-Z diagram of atomic nuclei. Black dots show stable kernels. The area of \u200b\u200bthe location of stable nuclei is usually called the valley of stability. On the left side of the stable nuclei there are kernels, overloaded with protons (protono-envelope kernels), on the right - the nuclei overloaded with neutrons (neutronesupply kernels). The proton-enforcement cores are radioactive and are converted into stable mainly as a result of β + -sepad, the proton, which is included in the nucleus in this case turns into a neutron. Neutron enforcement cores are also radioactive and are converted to stable as a result of β---representatives, with the transformation of the neutron kernel into the proton.

N-Z atomic nuclei diagram

The most severe stable isotopes are lead isotopes (z \u003d 82) and bismuth (Z \u003d 83). Heavy kernels along with the processes of β + and β - - decay are also susceptible to - asset and spontaneous division that becomes their main decay channels. The dotted line outline the area of \u200b\u200bthe possible existence of atomic nuclei. Line B P \u003d 0 (B P - the energy of the proton separation) limits the area of \u200b\u200bthe existence of atomic nuclei on the left (Proton Drip-Line). Line B n \u003d 0 (B n - neutron separation energy) - right (Neutron Drip-Line). Outside of these borders, the atomic nuclei cannot exist, as they disintegrate in the characteristic nuclear time (~ 10 -23 c) \u200b\u200bwith the emission of one or two nucleons.

The nuclear density is 10 17 kg / m 3.

The back of the nucleons form the resulting spin of the nucleus, summing up according to the quantum laws of the addition of the moments. With an odd number of nucleons, the spin kernel will be half apected, with an even number of nucleons - zero or an integer. The backs of most nucleons in the kernel mutually compensate each other, located antipherally. Therefore, the backs of the nuclei do not exceed several units. In nuclei with an even number of protons and even numbers of neutrons (even-even nuclei), the spin is zero.

Delimo is the atomic core? And if so, then from which particles it consists? Many physicists tried to answer this question.

In 1909, British physicist Ernest Rutherford, together with the German physicist, Hans Heiger and physicist from New Zealand, Ernst Marsden, held his known experiment on the scattering of α-particles, resulting in the result that the atom was not an indivisible particle. It consists of a positively charged kernel and electrons rotating around it. Moreover, despite the fact that the size of the nucleus is approximately 10,000 times smaller than the size of the atom itself, 99.9% of the mass of the atom are concentrated.

But what is the core of the atom? What particles are included in its composition? It is now we know that the kernel of any element consists of protons and neutron, the general name of which Nucleons. And at the beginning of the twentieth century after the appearance of the planetary, or nuclear, atom model, it was a mystery to many scientists. Different hypotheses have been put forward and various models were offered. But the correct answer to this question again gave Rutherford.

Opening Proton

Experience Rutford

The kernel of the hydrogen atom is a hydrogen atom, from which its single electron was removed.

By 1913, the mass and charge of the hydrogen atom of the hydrogen were calculated. In addition, it became known that the mass of the atom of any chemical element is always divided without a residue on the mass of the hydrogen atom. This fact caused Rutherford to think that any core includes the kernels of hydrogen atoms. And he managed to prove it experimentally in 1919.

In their own experience, Rutherford placed the source of α-particles into the chamber in which the vacuum was created. The thickness of the foil that closed the chamber window was such that the α particles could not go out. The camera was located outside the chamber window, which was covered with sulfur zinc.

When the camera began to fill in nitrogen, light flashes were recorded on the screen. This meant that under the influence of α-particles from nitrogen, some new particles were knocked out, without difficulty penetrating a foil, impassable for α-particles. It turned out that unknown particles have a positive charge equal to the magnitude of the electron charge, and their mass is equal to the mass of the hydrogen atom. These particles Rangeford called protons.

But soon it became clear that the nuclei of atoms consist not only from the protons. After all, if it were so, the mass of the atom would be equal to the sum of the masses of protons in the core, and the ratio of the charge of the nucleus to the mass would be the magnitude of constant. In fact, this is true only for the simplest hydrogen atom. In the atoms of other elements, everything is different. For example, in the kernel of the beryllium atom, the sum of the mass of protons is equal to 4 units, and the mass of the nucleus itself is 9 units. So, in this core there are other particles with a mass of 5 units, but not having a charge.

Opening neutron

In 1930, the German physicist Walter Bot Bote and Hans Becker during the experiment found that radiation arising from the bombardment of the beryllium atoms α-particles has a huge penetrating ability. Two years later, the English physicist James Chadwick, the student of Rutherford, found out that even a lead plate with a thickness of 20 cm, placed on the way of this unknown radiation, does not weaken and does not strengthen it. It turned out that the electromagnetic field does not have any impact on radiated particles. This meant that they do not have a charge. Thus, another particle was discovered, which is included in the kernel. She was called neutron. The neutron mass turned out to be equal to the mass of the proton.

Proton-neutron kernel theory

After the experimental opening of the neutron, the Russian scientist D. D. Ivanenko and the German physicist V. Heisenberg, independently of each other offered the proton-neutron theory of the nucleus, which gave the scientific substantiation of the composition of the nucleus. According to this theory, the kernel of any chemical element consists of protons and neutrons. Their common name - nucleons.

The total number of nucleons in the kernel is denoted by the letter A.. If the number of protons in the kernel designate the letter Z., and the number of neutrons of the letter N., I get expression:

A \u003d.Z +.N.

This equation is called ivanenko-Heisenberg equation.

Since the charge of the atom nuclei is equal to the number of protons in it, then Z. Call as well charging number. The charge number, or atomic number, coincides with its sequence number in the periodic system of Mendeleev elements.

In nature, there are elements whose chemical properties are absolutely the same, and mass numbers are different. Such elements are called isotopes. Isotopes have the same number of protons and a different amount of neutrons.

For example, hydrogen has three isotopes. All of them have a sequence number equal to 1, and the number of neutrons in the kernel they have different. So, in the simplest isotope of hydrogen, distance, mass number 1, in the core 1 proton and a single neutron. This is the simplest chemical element.

Atomic kernel - The central part of the atom in which its main mass is concentrated (more than 99.9%). The kernel is charged positively, the charge of the nucleus determines the chemical element to which the atom belongs.

The atomic core consists of nucleons - positively charged protons and neutral neutrons that are interconnected by means of strong interaction.

The atomic kernel, considered as a class of particles with a certain number of protons and neutrons, is customary called nuclide.

The number of protons in the kernel is called its charge number - this number is equal to the sequence number of the element to which the atom refers in the table (periodic system of elements) of Mendeleev. The number of protons in the nucleus determines the structure of the electronic shell of the neutral atom and, thus, the chemical properties of the corresponding element. The number of neutrons in the kernel is called it isotopic number . The kernels with the same number of protons and different numbers of neutrons are called isotopes. The kernel with the same number of neutrons, but different number of protons - are called isotones.

The total number of nucleons in the kernel is called its mass number () and approximately equal to the average mass of the atom indicated in the Mendeleev table. Nuclides with the same massive number, but by different proton-neutron composition it is customary to call by isobami.

Weight

Due to the difference among neutrons, the isotopes of the element have a different mass, which is an important characteristic of the kernel. In nuclear physics, the mass of the nuclei is made to measure in atomic units of the mass ( but. eat.), for one a. e. m. Take 1/12 part of the mass of nuclide 12 C [CH 2]. It should be noted that the standard mass, which is usually given for nuclide, is the mass of a neutral atom. To determine the mass of the nucleus, it is necessary to calculate the sum of the masses of all electrons from the mass of the atom (the more accurate value is, if you also consider the electron communication energy with the kernel).

In addition, the energy equivalent of the masses is often used in nuclear physics. According to the ratio of Einstein, the total energy corresponds to each mass value:

Where is the speed of light in vacuo.

The ratio between a. e. m. and its energy equivalent in Joules:

and since 1 electronof \u003d 1,602176 · 10 -19 J, the energy equivalent A. e. m. MeV is equal

Radius

An analysis of the collapse of heavy cores clarified the assessment of Rangeford [CH 3] and connected the radius of the kernel with a massive number by a simple ratio:

where is the constant.

Since the radius of the nucleus is not a purely geometric characteristic and is primarily associated with the radius of the actions of nuclear forces, the value depends on the process, when analyzing which the value was obtained, the average value of M, so the kernel radius in meters

Charge

The proton number in the kernel determines its electrical charge directly, the isotopes have the same number of protons, but a different amount of neutrons. .

For the first time, the charges of atomic nuclei identified Henry Cosli in 1913. The scientist interpreted his experimental observations by the dependence of the X-ray wavelength from a certain constant varying per unit from the element to the element and equal unit for hydrogen:

where

And - permanent.

Nuclear communication energy.

The core binding energy is minimal energy that needs to be expensive to complete the kernel splitting into separate particles. From the law of conservation of energy it follows that the bond energy is equal to the energy that is allocated during the formation of the nucleus from individual particles.

The binding energy of any nucleus can be determined using accurate measurement of its mass. Currently, physicists have learned to measure the masses of particles - electrons, protons, neutrons, nuclei, etc. - with very high accuracy. These measurements show that mass of any nucleus M. I always have less than the sum of the masses of the protons and neutrons:

This energy is released during the formation of the kernel in the form of radiation of γ-quanta.

Nuclear power.

Nuclear power are short-range Forces. They are manifested only on very low distances between nucleons in the kernel of about 10 -15 m. Length (1.5 - 2.2) · 10 -15 m is called radius of the actions of nuclear forces.

Nuclear forces are detected charging independence : Attraction between two nucleons is equally independent of the charge state of the nucleons - proton or neutron. The charge independence of nuclear forces is visible from comparison of communication energies mirror kernels . So called nuclei, in which the same overall number of nucleons, But the number of protons in one is equal to the number of neutrons by another.

Nuclear power possess property saturation , which manifests itself in, that the nucleon in the kernel interacts only with a limited number of neighboring nucleons closest to it. That is why there is a linear dependence of the energies of the nuclear communication from their mass numbers A.. Practically complete saturation of nuclear forces is achieved in the α particle, which is very sustainable education.

Nuclear forces depend on orientation of spins interacting nucleons. This is confirmed by the different nature of neutron scattering by ortho and parasodorodore molecules. In the molecule of the orthodorod of the back of both protons are parallel to each other, and in the molecule of the paraguodor, they are anti-parallel. Experiments have shown that the scattering of neutrons on a parachodode is 30 times the scattering on the orthoder plant. Nuclear forces are not central.

So, list general properties of nuclear forces :

· Small radius of the actions of nuclear forces ( R. ~ 1 FM);

· Great nuclear potential U. ~ 50 MeV;

· The dependence of nuclear forces from spins of interacting particles;

· The tensor nature of the interaction of nucleons;

· Nuclear forces depend on the mutual orientation of the spin and orbital moments of nucleon (spin-orbital forces);

· Nuclear interaction has the property of saturation;

· Charge independence of nuclear forces;

· The overall nature of nuclear interaction;

· Attraction between nucleons at large distances ( r. \u003e 1 FM), replaced by repellent on small ( r. < 0,5 Фм).