Makhov B.F.
In connection with the development by the author of the “Vibrational Model of the Neutral Atom” with the inclusion of the “world ether”, in which the concepts of “permanent positive charge of the atomic nucleus” and “Coulomb field” become redundant, the question arises of a new formulation of the Periodic Law. Such a formulation is proposed in this article, where the problem of the mathematical expression of the Periodic Law is also considered. In the article, the author uses his own version of the "Symmetric Quantum Periodic System of Neutral Atoms (SC-PSA)", adequate to the Vibrational Model.
More and more away from us 1869 - the time of the first formulation of the Periodic Law by D.I. Mendeleev (PZM) and his development of the Periodic Table of Elements (PSE-M), in which the atomic weight of the element was taken as the main ordering criterion, a more or less understandable characteristic then available. But even Dmitry Ivanovich himself said that "we do not know the reasons for the periodicity." At that time, only 63 elements were known, and their properties (mostly chemical) were known little and not always accurately.
Nevertheless, the problem of systematization of elements has already declared itself and required a solution. Mendeleev's ingenious intuition allowed him to successfully (at the then level of knowledge) cope with the task. His formulation of the PZM (October 1971): “... the properties of the elements, and therefore the properties of the simple and complex bodies, stand in a periodic relationship with their atomic weight.
Dmitry Ivanovich arranged all the elements in a series (Mendeleev's series) in order of increasing atomic weight, in which, however, he also allowed deviations for known pairs of elements (based on chemical properties), i.e. in fact, there is a dependence not only on atomic weight.
It became clear to scientists that when moving from one element in the PSE-M to the next, some characteristic of the element increases in steps by the same amount. This value is Z was called the serial number (mainly by chemists) or atomic number (by physicists). It turned out that the atomic weight itself in a certain way depends on Z. Therefore, as the main ordering criterion, the serial number Z was adopted, which, accordingly, was included in the 2nd formulation of the PZM instead of atomic weight.
Time passed, and new possibilities of systematization appeared. First of all, these are advances in the study of line optical spectra (LOS) of neutral atoms and characteristic X-ray radiation (XXR). It turned out that each element has a unique spectrum and a number of new elements were discovered from them. Quantum numbers, spectral terms, W. Pauli's exclusion principle, G. Moseley's law, etc. were proposed to describe the spectra. The study of atoms culminated in the creation of the first models of the atom (MOA), after the death of D. I. Mendeleev.
Moseley's law, which related the frequency of the characteristic x-ray radiation to the serial number Z, made a particularly great contribution to science. He confirmed the correctness of the Mendeleev series and made it possible to indicate the numbers of the remaining undiscovered elements. But then, guided by good intentions, to give a serial number Z physical meaning, physicists at the level of knowledge of the early 19th century (the first models of the atom) came to a hasty conclusion that it cannot be anything else than a constant positive electric charge of the atomic nucleus (the number of elementary electric charges - eZ).
As a result, scientists came to the conclusion that a refined 2nd formulation of the PZM is needed, in which the constant positive electric charge of the atomic nucleus of an element was taken as the main systematization criterion.
But, unfortunately, at the beginning of the 20th century, the first models of the atom were presented too mechanistically (planetary nuclear models), and the electrical neutrality of the atom as a whole was represented by the positive charge of the nucleus and the corresponding number of negative elementary particles - electrons, i.e. also at the level of primitive knowledge of that time about electricity. As a result, the concept of a constant Coulomb electric field was used, which attracts electrons rotating around the nucleus, etc. And God forbid the electron fall on the nucleus!
The discovery of the wave nature of the electron and many problems with the accepted model of the atom, they led to the transition to the "quantum mechanical model of the atom". Quantum mechanics (QM) has been hailed as the greatest achievement of the 20th century. But over time, the enthusiasm subsided. The reason is the shaky foundation on which the CME is built, based on the Schrödinger equation, which " describes motion of an electron. First of all, the approach itself is wrong - instead of considering the equilibrium quantum state of a neutral atom as a whole (at the macro level, speaking in the language of synergetics), the motion of an electron is considered in CME (i.e., they work at an excessively detailed micro level). Imagine that for the case of an ideal gas, instead of considering it at the macro level with time-constant parameters of the state of the gas (pressure, temperature, volume), they would suddenly begin to write the equations of motion for each of the billions of atoms and molecules of the gas, moaning loudly at the same time about the difficulty of the task and the insufficient power of modern computers. While at the macrolevel, the whole picture is easily and elegantly described using the equation for the connection of gas state parameters - the Clapeyron-Mendeleev equation. [FES, M, SE, 1984, p.288]
Something similar in complexity offers us the CME in the person of its founding fathers, especially for the case of atoms with large atomic numbers. However, Academician Lev Landau (1908-68), himself one of the pillars of the CME, already wrote: “An atom with more than one electron is complex system electrons interacting with each other. For such a system, one can, strictly speaking, consider only the states of the system as a whole. The same idea can be found in the works of the spectroscopy physicist Acad. Academy of Sciences of the BSSR Elyashevich M.A. (1908-95).
However, let us return to the consideration of the formulations of the Periodic Law. The modern (refined 2nd) formulation of the PZM is as follows:
"The properties of the elements are in a periodic relationship with the charge of their atomic nuclei." Nuclear charge eZ = atomic (serial) number of the element in the system, multiplied by the elementary electric charge (i.e. Z is numerically equal to the number of elementary electric charges).
Why is a new, 3rd formulation of the PZM needed?
1) From the 2nd formulation it is not very clear what properties are in question - if they are chemical, then they are not directly related to the elements (neutral atoms). When neutral atoms interact, their variable EMFs overlap, as a result, they exert a certain degree of excitation on each other. To describe a chemical bond, you need to know additionally - what is connected to what (composition and structure of the substance) and under what specific physical conditions (CFU), etc.
2) According to the “Vibrational Model” developed by the author, the nucleus of a neutral atom has neither a constant electric charge nor a constant Coulomb field created by it (instead of this, a pulsating nucleus, an alternating electromagnetic field - EMF, standing EMW, parametric resonance, high quality factor of oscillations, durability atom). See FI, 2008, No. 3, p.25
3) That is, there is no clear definition of either an argument or a function. As for the nature of the periodic dependence, there is also no certainty. The PZM is useless without simultaneously considering the table of the Periodic Table itself, which is why it is often not mentioned at all in textbooks in its current formulation (“vicious circle”). It is no coincidence that we still do not have a complete theory of the Periodic system and the most mathematical expression of the PZM.
4) Now you can use fundamentally new opportunities for a more correct formulation of the Periodic Law and the derivation of its mathematical expression, which give"Vibrational model of a neutral atom" (coupled vibrations of the nucleus and its environment) and "Symmetric quantum periodic system of neutral atoms (SC-PSA)", developed and published by the author.
5) According to the synergetic approach, the equilibrium quantum state of the atom as a whole (macroscopic approach) can be described by several time-independent parameters. The author has shown that they are a strictly individual (W. Pauli exclusion principle) set of 4 quantum numbers inherent in each atom, determined from its LOS (and not from the CME equations).
Such a set of quantum numbers uniquely determines the place of the element (its coordinates) in the SC-PSA developed by the author.
6) Such parameters must meet a number of requirements:
Respond to the physical nature of a neutral atom (according to the "Vibrational Model")
Be unambiguous
Be integer (which follows from the very essence of the radiation of the nucleus)
It is easy to measure (from the spectra of a neutral atom).
Thus, the meaning of quantum numbers known for each atom must be refined according to their physical nature.
7) Instead of E. Schrödinger's CME equation, the author proposes to use the quantum number connection equations (Makhov's equations) (the author found two such equations), which are the mathematical expression of the PZM, adequate to the new formulation. More on this in a forthcoming book.
8) In the light of the “Vibrational Model of the Neutral Atom” and the new idea of the variable EMF of the nucleus, for the new formulation of the Periodic Law, instead of the elementary electric charge, another physical quantity is needed, which, together with the ordinal number Z, characterizes the intensity of the electromagnetic interaction (gradually changing with increasing Z) and uniquely determined from the spectrum of neutral atoms. And there is such a value - it is the fine structure constant (α) [FES-763], which is usually used in searches for the "upper boundary of the Periodic Table".
New wording of the PZM looks like that:
"The characteristics of neutral atoms are in a periodic dependence on the magnitude of the tension (aZ) alternating electromagnetic field (EMF) created by their nuclei. The author arrived at such a brief formulation on November 22, 2006, after a series of "lengthy" ones.
It can be seen from it that instead of the magnitude of the electric charge ( eZ), which includes an elementary electric charge, the intensity value is used ( aZ), which includes α - fine structure constant, which “in quantum electrodynamics is considered as a natural parameter characterizing the “strength” of electromagnetic interaction” [FES, p.763].
We have already spoken about the characteristics of neutral atoms (about quantum numbers, their physical nature, etc.), but the nature of the periodic dependence still needs to be clarified a little. Already now there are prerequisites for the derivation of the equations of connection of quantum numbers - this is (n+ l)- rules of academician V.M. Klechkovsky (1900-72) and (n- l)- dhn rule, prof. D.N. Trifonov, which were used by the author to construct the SC-PSA. Keeping in mind the variable EMF and the standing EMW propagating (to a specific depth for each atom), we can say that the sum of these quantum numbers represents the total energy of the standing EMW, and the difference is the depth of change in the oscillation parameter. That is, there are already bundles of quantum numbers that represent in the SC-PSA (n+ l)- period (they are all paired and form dyads), and (n- l)- groups of consecutive atoms - horizontal rows of SC-PSA (up to 4 in a period within Z ≤ 120), which are sequences f-, d-, p-, s- elements. That is, at one quantum energy level there can be several quantum states. Further consideration of the features of the two-unit standing EMW allows us to derive the equations for the connection of quantum numbers (Makhov's equations).
Example: Total standing EMW energy E n + l = E n + E l = const, where E n and E l - the average values of the energy of the electric and magnetic components of its parts.
To clarify the physical meaning of quantum numbers, we use the formula for the energy of a quantum emitter (in general view) E = Eo (2k + 1), hence → = 2k
Specifically, we have for E n + l= E o (2 + 1) → = n + l , that is the sum of quantum numbers (n+ l) is the ratio of the increment of the total energy of a standing EMW to its initial value, which gives a physical meaning to the above-mentioned first rule of academician V.M. Klechkovsky.
A standing EMW is a material carrier of parametric resonance (with a constant internal energy, energy is transferred from electrical to magnetic and vice versa with a huge frequency). In this case, the difference between the average values of the energy of the electric and magnetic components of the total energy of the EMW E n - l = E n - E l - the amount of parameter change is also quantized.
E n - l= E o (2 + 1) → = n - l , this attitude gives physical meaning to D.N. Trifonov’s rule and from here the rule becomes clear n - l ≥ 1, since otherwise there is no standing EMW (there should not be inherent in the traveling wave n = l, and associated energy loss). You can introduce the concept of "relative value of parameter change" : = = λ
The average values of the components of the total energy of the standing EMW are also quantized
E n=Eo(2 n + 1) → = 2n
E l=Eo(2 l + 1) → = 2l
hence the quantum numbers n and l acquire a new physical meaning as the quantum numbers of the components of the electric and magnetic energies of the total energy of a standing EMW (instead of the "principal quantum number" and "orbital quantum number").
The high and constant frequency of the standing EMW is expressed through periodic functions, in relation to our case - trigonometric. The duality of the standing EMW is in the parametric assignment of the function. A standing EMW as a harmonic wave can be described by sinusoidal equations of the form y = A sin (ω t + φ ),
then n t = n cosα and lt = l sin α (parametric definition of an ellipse).
here n and l - quantum numbers (dimensionless integer values), indicators of the maximum amplitude of the relative energy of the electric and magnetic components of the standing EMW, and n t and lt- current values of fluctuating quantities ( standing EMW components) in this moment time, i.e. quantities are also dimensionless.*)
0 ≤ |n t| ≤n 0 ≤ |l t | ≤l
Let us clarify that there are exactly two dependencies- cosine and sinusoid At the interface "Nucleus-environment" at the initial moment of radiation, the first has a maximum amplitude - to = n (otherwise there is no radiation), and the amplitude is different - to = 0 (i.e. there is a phase shift). Starting to propagate from the core, one component of the standing EMW generates another and vice versa. The author would like to caution against jumping to the conclusion that to = 0, then the magnetic component of the total energy of the standing EMW is also equal to zero. This is not so, it is enough to recall the formula of a quantum harmonic emitter.
This is the equation of the ellipse + = 1 (in canonical form, common for the connection of harmonic oscillations) and is one of the equations for the connection of quantum numbers.
The physical meaning of this coupling equation becomes clearer if some transformations are made. To do this, we use the representation of the ellipse as hypotrochoids.
For our case ; .
This is the 1st quantum number relation equation (Makhov's equation).
Or clear enough 
.
It can be seen that the equation reflects the constancy of the total energy of a standing EMW. Thus, the above bundles of quantum numbers ( n+l) is the period number in SC-PSA, and ( n - l)- defines the sequence of location of the horizontal rows included in the period - found their place in the equation of communication, and the equation itself well reflects the structure of the SC-PSA.
We have obtained one more, 2nd connection equation for the remaining two quantum numbers (from the complete set in accordance with the W. Pauli exclusion principle) - m l andm s , but you can’t say about them in a nutshell, and even with the physical meaning of the “spin” quantum number m s still needs to be figured out - see here.
Beginning (serial number of the original element - Z M) of each M-dyad (a pair of SC-PSA periods) can be obtained from the identical transformation of the formula by V.M. Klechkovsky for the number Zl element at which the first time an element with data appears value lmax
Z M = Zl -1 = = ,
then atlmax = 0; 1; 2; 3; 4... we have Z M= 0; 4; 20; 56; 120..., i.e. these are the so-called tetrahedral numbers, which is indirectly related to some minimum initial quantum energy levels for the dyad (a tetrahedron among all spatial bodies has a minimum surface area with a fixed volume).
In more detail on this subject and the mentioned two equations of connection of quantum numbers, the author intends to report in the papers being prepared for publication.
The author does not claim this work, of course, to create a complete theory of the Periodic system of neutral atoms and its mathematical expression, but he considers it a necessary and important stage on this path, and to the best of his ability will contribute to further progress.
BIBLIOGRAPHY:
- Klechkovsky V.M. "The distribution of atomic electrons and the successive filling rule (n+ l)- group”, M., Atomizdat, 1968
- Klechkovsky V.M. “Development of some theoretical problems of the Periodic system of D.I. Mendeleev" (report at the symposium of the X Mendeleev Congress). M., Nauka, 1971, pp. 54-67.
- Trifonov D.N. "Structure and boundaries of the periodic system", Moscow, Atomizdat, 1976, 271 pages.
- Makhov B.F., book "Symmetric Quantum Periodic System of Elements" (SK-PSE), Moscow, 1997 - ISBN 5-86700-027-3
- Makhov B.F., Article "Symmetric quantum periodic system of elements (neutral atoms) - SC-PSA (or New Periodization of the Periodic System", in the journal RAE "Fundamental Research", 2007, No. 9, pp. 30-36 - ISSN 1812 -7339
- Makhov B.F., Report "The manifestation of pairing in the Periodic system of neutral atoms (SC-PSA)", in Proceedings of the V-Int. conference "Biniology, symmetrology and synergetics in natural sciences", Sept. 2007, Tyumen, Tsogu, Section "Physics and Chemistry", pp. 59-65 ISBN 978-5-88465-835-4
- Makhov B.F., Article "World broadcast" D.I. Mendeleev and his place in the Periodic system”, in the RANH journal “Fundamental Research”, 2008, no. 3, p. 25-28
- Makhov B.F., Article "The physical nature of metals in the light of the vibrational model of the atom", in the journal of the Russian Academy of Natural Sciences "Fundamental Research", 2008, No. 3, p. 29-37
- Landau L.D., Lifshits E.M. "Quantum mechanics. Non-relativistic theory”, Moscow: Nauka, 1974 (3rd ed.). pp. 293. and 1989 (4th ed.). page 302
- Makhov BF, book "On the model of the neutral atom and ways out of the crisis in atomic physics" (prepared for publication).
- Makhov B.F., the book "Three-dimensional SC-PSA" (prepared for publication).
- Bronstein I.N., Semendyaev K.A., Handbook of mathematics for engineers and students of higher educational institutions. Moscow: Nauka, Editor-in-Chief. FML, 1986 (13e, corr.), p.127
- Article "Fine structure constant", Physical encyclopedic Dictionary- FES, p.763
Bibliographic link
Makhov B.F. PERIODIC LAW D.I. MENDELEEV - NEW FORMULATION AND MATHEMATICAL EXPRESSION OF THE LAW // Successes of modern natural science. - 2008. - No. 9. - P. 24-29;URL: http://natural-sciences.ru/ru/article/view?id=10547 (date of access: 02/29/2020). We bring to your attention the journals published by the publishing house "Academy of Natural History"
Here the reader will find information about one of the most important laws ever discovered by man in the scientific field - the periodic law of Mendeleev Dmitry Ivanovich. You will get acquainted with its meaning and influence on chemistry, will be considered general provisions, characteristics and details of the periodic law, the history of the discovery and the main provisions.
What is the periodic law
The periodic law is natural law of a fundamental nature, which was first discovered by D. I. Mendeleev back in 1869, and the discovery itself occurred due to a comparison of the properties of some chemical elements and the atomic mass values known at that time.
Mendeleev argued that, according to his law, simple and complex bodies and various compounds of elements depend on their dependence of the periodic type and on the weight of their atom.
The periodic law is unique in its kind and this is due to the fact that it is not expressed by mathematical equations, unlike other fundamental laws of nature and the universe. Graphically, it finds its expression in the periodic table of chemical elements.
Discovery history
The discovery of the periodic law took place in 1869, but attempts to systematize all known x elements began long before that.
The first attempt to create such a system was made by I. V. Debereiner in 1829. He classified all the chemical elements known to him into triads, interconnected by the proximity of half the sum atomic masses included in this group of three components. Following Debereiner, an attempt was made to create a unique table of classification of the elements by A. de Chancourtua, he called his system the "earth spiral", and after him the Newlands octave was compiled by John Newlands. In 1864, almost simultaneously, William Olding and Lothar Meyer published independently created tables.
The periodic law was presented to the scientific community for review on March 8, 1869, and this happened during a meeting of the Russian X-th society. Mendeleev Dmitry Ivanovich announced his discovery in front of everyone, and in the same year Mendeleev's textbook "Fundamentals of Chemistry" was published, where the periodic table created by him was shown for the first time. A year later, in 1870, he wrote an article and submitted it for review to the RCS, where the concept of the periodic law was first used. In 1871, Mendeleev gave an exhaustive description of his research in his famous article on the periodic validity of chemical elements.
An invaluable contribution to the development of chemistry
The value of the periodic law is incredibly great for the scientific community around the world. This is due to the fact that its discovery gave a powerful impetus to the development of both chemistry and other natural sciences, such as physics and biology. The relationship of the elements with their qualitative chemical and physical characteristics was open, and this also made it possible to understand the essence of building all the elements according to one principle and gave rise to the modern formulation of the concepts of chemical elements, to concretize the knowledge of the idea of substances of complex and simple structure.
The use of the periodic law made it possible to solve the problem of chemical prediction, to determine the cause of the behavior of known chemical elements. Atomic physics, including nuclear energy, became possible as a result of the same law. In turn, these sciences made it possible to expand the horizons of the essence of this law and delve into its understanding.
Chemical properties of the elements of the periodic system
In fact, the chemical elements are interconnected by the characteristics inherent in them in the state of both a free atom and an ion, solvated or hydrated, in a simple substance and in the form that their numerous compounds can form. However, x-th properties usually consist in two phenomena: properties characteristic of an atom in a free state, and a simple substance. This kind of properties includes many of their types, but the most important are:
- Atomic ionization and its energy, depending on the position of the element in the table, its ordinal number.
- The energy relationship of the atom and electron, which, like atomic ionization, depends on the location of the element in the periodic table.
- The electronegativity of an atom, which does not have a constant value, but can change depending on various factors.
- The radii of atoms and ions - here, as a rule, empirical data are used, which is associated with the wave nature of electrons in a state of motion.
- Atomization of simple substances - a description of the ability of an element to reactivity.
- The oxidation states are a formal characteristic, however, appearing as one of the most important characteristics of an element.
- The oxidation potential for simple substances is a measurement and indication of the potential of a substance to act in aqueous solutions, as well as the level of manifestation of redox properties.
Periodicity of elements of internal and secondary type
The periodic law gives an understanding of another important component of nature - internal and secondary periodicity. The aforementioned fields of study of atomic properties are, in fact, much more complex than one might think. This is due to the fact that the elements s, p, d of the table change their qualitative characteristics depending on their position in the period (internal periodicity) and group (secondary periodicity). For example, the internal process of the transition of the element s from the first group to the eighth to the p-element is accompanied by minimum and maximum points on the energy curve of the ionized atom. This phenomenon shows the internal inconstancy of the periodicity of changes in the properties of an atom according to its position in the period.
Results
Now the reader has a clear understanding and definition of what Mendeleev's periodic law is, realizes its significance for man and the development of various sciences, and has an idea of its current provisions and the history of discovery.
As a result of the successful development of the material in this chapter, the student should:
know
- modern formulation of the periodic law;
- connection between the structure of the periodic system and the energy sequence of sublevels in multielectron atoms;
- definitions of the concepts "period", "group", "5-elements", "p-elements", "d- elements”, “/-elements”, “ionization energy”, “electron affinity”, “electronegativity”, “van der Waals radius”, “clarke”;
- basic law of geochemistry;
be able to
Describe the structure of the periodic system in accordance with the rules of Klechkovsky;
own
Ideas about the periodic nature of the change in the properties of atoms and the chemical properties of elements, about the features of the long-period version of the periodic system; about the relationship of the abundance of chemical elements with their position in the periodic system, about macro- and microelements in the lithosphere and living matter.
Modern formulation of the periodic law
Periodic law - the most general law of chemistry - was discovered by Dmitry Ivanovich Mendeleev in 1869. At that time, the structure of the atom was not yet known. D. I. Mendeleev made his discovery based on the regular change in the properties of elements with an increase in atomic masses.
After the discovery of the structure of atoms, it became clear that their properties are determined by the structure of electron shells, which depends on total number electrons in an atom. The number of electrons in an atom is equal to the charge of its nucleus. Therefore, the modern formulation of the periodic law is as follows.
The properties of chemical elements and the simple and complex substances they form are in a periodic dependence on the charge of the nucleus of their atoms.
The significance of the periodic law lies in the fact that it is the main tool for systematizing and classifying chemical information, a very important means of interpreting chemical information, a powerful tool for predicting the properties of chemical compounds, and a means of directed search for compounds with predetermined properties.
The periodic law does not have a mathematical expression in the form of equations, it is reflected in a table called periodic system of chemical elements. There are many variants of the tables of the periodic table. The most widely used are the long-period and short-period versions, placed on the first and second color inserts of the book. The main structural unit of the periodic system is the period.
Period with number p called a sequence of chemical elements arranged in ascending order of the charge of the nucleus of an atom, which begins with ^-elements and ends with ^-elements.
In this definition P - period number equal to the main quantum number for the upper energy level in the atoms of all elements of this period. in atoms s-elements 5-sublevels are completed, in atoms p-elements - respectively p-sublevels. The exception to the above definition is the first period, in which there are no p-elements, since at the first energy level (n = 1) there is only 15-level. The periodic table also contains d-elements, whose ^-sublevels are completed, and /-elements, whose /-sublevels are completed.
Periodic law of DIMendeleev, its modern formulation. What is its difference from the one given by D.I. Mendeleev? Explain what is the reason for such a change in the wording of the law? What is the physical meaning of the Periodic Law? Explain the reason for the periodic change in the properties of chemical elements. How do you understand the phenomenon of periodicity?
The periodic law was formulated by D. I. Mendeleev in the following form (1871): “properties simple bodies, as well as the forms and properties of the compounds of elements, and therefore the properties of the simple and complex bodies formed by them, stand in a periodic dependence on their atomic weight.
At present, the Periodic Law of D. I. Mendeleev has the following formulation: “the properties of chemical elements, as well as the forms and properties of the simple substances and compounds they form, are in a periodic dependence on the magnitude of the charges of the nuclei of their atoms.”
A feature of the Periodic Law among other fundamental laws is that it does not have an expression in the form of a mathematical equation. The graphical (tabular) expression of the law is the Periodic Table of Elements developed by Mendeleev.
The periodic law is universal for the Universe: as the well-known Russian chemist N. D. Zelinsky figuratively noted, the Periodic law was “the discovery of the interconnection of all atoms in the universe”.
In its current state, the Periodic Table of the Elements consists of 10 horizontal rows (periods) and 8 vertical columns (groups). The first three rows form three small periods. Subsequent periods include two rows. In addition, starting from the sixth, periods include additional series of lanthanides (sixth period) and actinides (seventh period).
Over the period, there is a weakening of the metallic properties and an increase in non-metallic ones. The end element of the period is a noble gas. Each subsequent period begins with an alkali metal, i.e., as the atomic mass of the elements increases, the change in chemical properties has a periodic character.
With the development of atomic physics and quantum chemistry, the Periodic Law received a rigorous theoretical justification. Thanks to the classical works of J. Rydberg (1897), A. Van den Broek (1911), G. Moseley (1913), the physical meaning of the ordinal (atomic) number of an element was revealed. Later, a quantum mechanical model was created for the periodic change in the electronic structure of atoms of chemical elements as the charges of their nuclei increase (N. Bohr, W. Pauli, E. Schrödinger, W. Heisenberg, and others).
Periodic properties of chemical elements
In principle, the properties of a chemical element combine all, without exception, its characteristics in the state of free atoms or ions, hydrated or solvated, in the state of a simple substance, as well as the forms and properties of the numerous compounds it forms. But usually, the properties of a chemical element mean, firstly, the properties of its free atoms and, secondly, the properties of a simple substance. Most of these properties show a clear periodic dependence on the atomic numbers of chemical elements. Among these properties, the most important, which are of particular importance in explaining or predicting the chemical behavior of elements and the compounds they form, are:
Ionization energy of atoms;
The energy of the affinity of atoms for an electron;
Electronegativity;
Atomic (and ionic) radii;
Energy of atomization of simple substances
oxidation states;
Oxidation potentials of simple substances.
The physical meaning of the periodic law is that the periodic change in the properties of the elements is in full accordance with the periodically renewed similar electronic structures of atoms at ever higher energy levels. With their regular change, physical and Chemical properties.
The physical meaning of the periodic law became clear after the creation of the theory of the structure of the atom.
So, the physical meaning of the periodic law is that the periodic change in the properties of elements is in full accordance with periodically renewing at ever higher energy levels similar electronic structures of atoms. With their regular change, the physical and chemical properties of the elements naturally change.
What is the physical meaning of the periodic law.
These conclusions reveal the physical meaning of the periodic law of D. I. Mendeleev, which remained unclear for half a century after the discovery of this law.
It follows from this that the physical meaning of the periodic law of D. I. Mendeleev consists in the periodicity of the repetition of similar electronic configurations with an increase in the main quantum number and the combination of elements according to the proximity of their electronic structure.
The theory of the structure of atoms has shown that the physical meaning of the periodic law is that with a successive increase in the charges of the nuclei, similar valence electronic structures of atoms are periodically repeated.
From all of the above, it is clear that the theory of the structure of the atom revealed the physical meaning of the periodic law of D. I. Mendeleev and even more clearly revealed its significance as the basis for the further development of chemistry, physics and a number of other sciences.
Replacing the atomic mass with the charge of the nucleus was the first step in revealing the physical meaning of the periodic law. Further, it was important to establish the causes of the occurrence of periodicity, the nature of the periodic function of the dependence of properties on the charge of the nucleus, to explain the magnitude of the periods, the number of rare earth elements, etc.
For analogous elements, there is the same number electrons on shells of the same name at different values of the principal quantum number. Therefore, the physical meaning of the Periodic Law lies in the periodic change in the properties of elements as a result of periodically renewing similar electron shells of atoms with a successive increase in the values of the main quantum number.
For elements - analogues, the same number of electrons is observed in the same orbitals at different values of the main quantum number. Therefore, the physical meaning of the Periodic Law lies in the periodic change in the properties of elements as a result of periodically renewing similar electron shells of atoms with a successive increase in the values of the main quantum number.
Thus, with a successive increase in the charges of atomic nuclei, the configuration of the electron shells is periodically repeated and, as a result, the chemical properties of the elements are periodically repeated. This is the physical meaning of the periodic law.
The periodic law of D. I. Mendeleev is the basis of modern chemistry. The study of the structure of atoms reveals the physical meaning of the periodic law and explains the patterns of changes in the properties of elements in periods and in groups of the periodic system. Knowledge of the structure of atoms is necessary to understand the reasons for the formation of a chemical bond. The nature of the chemical bond in molecules determines the properties of substances. Therefore, this section is one of the most important sections of general chemistry.
natural science periodical ecosystem
By the time the periodic law was discovered, 63 chemical elements were known and the properties of their various compounds were described.
The works of the predecessors of D.I. Mendeleev:
1. The Berzelius classification, which has not lost its relevance even today (metals, non-metals)
2. Debereiner triads (eg lithium, sodium, potassium)
4. Spiral-axis Shankurtur
5. Meyer curve
Participation of D.I. Mendeleev at the International Chemical Congress in Karlsruhe (1860), where the ideas of atomism and the concept of "atomic" weight, which is now known as "relative atomic mass", were established.
Personal qualities the great Russian scientist D.I. Mendeleev.
The ingenious Russian chemist was distinguished by the encyclopedic knowledge, the scrupulousness of the chemical experiment, the greatest scientific intuition, confidence in the truth of his position and hence the fearless risk in defending this truth. DI. Mendeleev was a great and wonderful citizen of the Russian land.
D.I. Mendeleev arranged all the chemical elements known to him in a long chain in ascending order of their atomic weights and noted segments in it - periods in which the properties of the elements and the substances formed by them changed in a similar way, namely:
one). The metallic properties weakened;
2) Non-metallic properties were enhanced;
3) The degree of oxidation in higher oxides increased from +1 to +7(+8);
4). The degree of oxidation of elements in hydroxides, solid salt-like compounds of metals with hydrogen increased from +1 to +3, and then in volatile hydrogen compounds from -4 to -1;
5) Oxides from basic through amphoteric were replaced by acid ones;
6) Hydroxides from alkalis, through amphoteric acids were replaced by acids.
The conclusion of his work was the first formulation of the periodic law (March 1, 1869): the properties of chemical elements and the substances formed by them are in a periodic dependence on their relative atomic masses.
Periodic law and the structure of the atom.
The formulation of the periodic law given by Mendeleev was inaccurate and incomplete, because it reflected the state of science at a time when the complex structure of the atom was not yet known. Therefore, the modern formulation of the periodic law sounds differently: the properties of chemical elements and the substances formed by them are in a periodic dependence on the charge of their atomic nuclei.
Periodic system and structure of the atom.
The periodic system is graphic display periodic law.
Each designation in the periodic system reflects some feature or pattern in the structure of the atoms of the elements:
The physical meaning of the number of the element, period, group;
Causes of changes in the properties of elements and substances formed by them horizontally (in periods) and vertically (in groups).
Within the same period, metallic properties weaken, and non-metallic properties increase, because:
1) The charges of atomic nuclei increase;
2) The number of electrons at the outer level increases;
3) The number of energy levels is constant;
4) The radius of the atom decreases
Within the same group (in the main subgroup), metallic properties are enhanced, non-metallic properties are weakened, because:
one). The charges of atomic nuclei increase;
2). The number of electrons in the outer level is constant;
3). The number of energy levels increases;
4). The radius of the atom increases
As a result of this, a causal formulation of the periodic law was given: the properties of chemical elements and the substances formed by them are in a periodic dependence on changes in the external electronic structures of their atoms.
The meaning of the periodic law and the periodic system:
1. Allowed to establish the relationship between the elements, combine them by properties;
2. Arrange the chemical elements in a natural sequence;
3. Open periodicity, i.e. repeatability of the general properties of individual elements and their compounds;
4. Correct and clarify the relative atomic masses of individual elements (from 13 to 9 for beryllium);
5. Correct and clarify the oxidation states of individual elements (beryllium +3 to +2)
6. Predict and describe properties, indicate the path of discovery of yet undiscovered elements (scandium, gallium, germanium)
Using the table, we compare the two leading theories of chemistry.
| Philosophical foundations of community | Periodic law of D.I. Mendeleev | Theory of organic compounds A.M. Butlerov | |
| 1. 1. Opening time | 1869 | 1861 | |
| II. Prerequisites. 1. Accumulation of factual material 2. 2. Work of predecessors 3. Congress of chemists in Karlsruhe (1860) 4. Personal qualities. | By the time the periodic law was discovered, 63 chemical elements were known and the properties of their numerous compounds were described. | Many tens and hundreds of thousands of organic compounds are known, consisting of only a few elements: carbon, hydrogen, oxygen, less often nitrogen, phosphorus and sulfur. | |
| - J. Berzellius (metals and non-metals) - I.V. Debereiner (triads) - D.A.R. Newlands (octaves) - L. Meyer | - J. Berzellius, J. Liebig, J. Dumas (radical theory); -J.Dumas, Ch.Gerard, O.Laurent (type theory); - J. Berzellius introduced the term "isomerism" into practice; -F.Vehler, N.N. Zinin, M. Berthelot, A. Butlerov himself (syntheses organic matter, collapse of vitalism); -F.A.Kukule (benzene structure) | ||
| DI. Mendeleev was present as an observer | A. M. Butlerov did not participate, but actively studied the materials of the congress. However, he took part in the congress of doctors and naturalists in Speyer (1861), where he made a report "On the structure of organic bodies" | ||
| Both authors were distinguished from other chemists by the encyclopedic nature of chemical knowledge, the ability to analyze and generalize facts, scientific forecasting, the Russian mentality and Russian patriotism. | |||
| III. The role of practice in the development of theory | DI. Mendeleev predicts and indicates the ways of discovering gallium, scandium and germanium, still unknown to science. | A.M. Butlerov predicts and explains the isomerism of many organic compounds. He himself carries out many syntheses | |
Topic quiz
Periodic law and periodic system of elements D.I. Mendeleev
1. How do the radii of atoms change in a period:
2. How do the radii of atoms change in the main subgroups:
a) increase b) decrease c) stay the same
3. How to determine the number of energy levels in an atom of an element:
a) by the serial number of the element b) by the group number
c) by row number d) by period number
4. How is the place of a chemical element in the periodic system of D.I. Mendeleev:
a) the number of electrons in the outer level b) the number of neutrons in the nucleus
c) the charge of the nucleus of an atom d) the atomic mass
5. How many energy levels does a scandium atom have: a) 1 b) 2 c) 3 d) 4
6. What determines the properties of chemical elements:
a) the value of the relative atomic mass b) the number of electrons on the outer layer
c) the charge of the nucleus of an atom d) the number of valence electrons
7. How do the chemical properties of elements change in a period:
a) metallic ones are strengthened b) non-metallic ones are strengthened
c) do not change d) non-metallic weaken
8. Indicate the element that leads the long period of the Periodic Table of Elements: a) Cu (No. 29) b) Ag (No. 47) c) Rb (No. 37) d) Au (No. 79)
9. Which element has the most pronounced metallic properties:
a) Magnesium b) Aluminum c) Silicon
10. Which element has the most pronounced non-metallic properties:
a) Oxygen b) Sulfur c) Selenium
11. What is the main reason for changing the properties of elements in periods:
a) in an increase in atomic masses
b) in a gradual increase in the number of electrons in the external energy level
c) in an increase in the number of electrons in an atom
d) in an increase in the number of neutrons in the nucleus
12. Which element heads the main subgroup of the fifth group:
a) vanadium b) nitrogen c) phosphorus d) arsenic
13. What is the number of orbitals on the d-sublevel: a) 1 b) 3 c) 7 d) 5
14. What is the difference between atoms of isotopes of one element:
a) number of protons b) number of neutrons c) number of electrons d) nuclear charge
15. What is an orbital:
a) a certain energy level at which an electron is located
b) the space around the nucleus where the electron is located
c) the space around the nucleus, where the probability of finding an electron is greatest
d) the trajectory along which the electron moves
16. In which orbital does the electron have the highest energy: a) 1s b) 2s c) 3s d) 2p
17. Determine what element 1s 2 2s 2 2p 1 is: a) No. 1 b) No. 3 c) No. 5 d) No. 7
18. What is the number of neutrons in an atom +15 31 P a)31 b)16 c)15 e)46
19. What element has the structure of the outer electronic layer ... 3s 2 p 6:
a) neon b) chlorine c) argon d) sulfur
20. Based on the electronic formula, determine what properties the element has 1s 2 2s 2 2p 5:
a) metal b) non-metal c) amphoteric element d) inert element
21. How many chemical elements in the sixth period: a) 8 b) 18 c) 30 d) 32
22. What is the mass number of nitrogen +7 N which contains 8 neutrons:
a)14 b)15 c)16 d)17
23. An element whose nucleus contains 26 protons: a) S b) Cu c) Fe d) Ca
