Periodic table of chemical elements (periodic table)- classification of chemical elements, establishing the dependence of various properties of elements on the charge of the atomic nucleus. The system is a graphic expression of the periodic law established by the Russian chemist D. I. Mendeleev in 1869. Its original version was developed by D.I. Mendeleev in 1869-1871 and established the dependence of the properties of elements on their atomic weight (in modern terms, on atomic mass). In total, several hundred options for depicting the periodic system (analytical curves, tables, geometric figures, etc.) have been proposed. In the modern version of the system, it is assumed that the elements are summarized in a two-dimensional table, in which each column (group) defines the main physical and chemical properties, and the rows represent periods that are to a certain extent similar to each other.

Periodic table of chemical elements by D.I. Mendeleev

PERIODS RANKS GROUPS OF ELEMENTS I II III IV V VI VII VIII I 1 H 1,00795 4,002602 helium II 2 Li 6,9412 Be 9,01218 B 10,812 WITH 12,0108 carbon N 14,0067 nitrogen O 15,9994 oxygen F 18,99840 fluorine 20,179 neon III 3 Na 22,98977 Mg 24,305 Al 26,98154 Si 28,086 silicon P 30,97376 phosphorus S 32,06 sulfur Cl 35,453 chlorine Ar 18 39,948 argon IV 4 K 39,0983 Ca 40,08 Sc 44,9559 Ti 47,90 titanium V 50,9415 vanadium Cr 51,996 chromium Mn 54,9380 manganese Fe 55,847 iron Co 58,9332 cobalt Ni 58,70 nickel Cu 63,546 Zn 65,38 Ga 69,72 Ge 72,59 germanium As 74,9216 arsenic Se 78,96 selenium Br 79,904 bromine 83,80 krypton V 5 Rb 85,4678 Sr 87,62 Y 88,9059 Zr 91,22 zirconium Nb 92,9064 niobium Mo 95,94 molybdenum Tc 98,9062 technetium Ru 101,07 ruthenium Rh 102,9055 rhodium Pd 106,4 palladium Ag 107,868 Cd 112,41 In 114,82 Sn 118,69 tin Sb 121,75 antimony Te 127,60 tellurium I 126,9045 iodine 131,30 xenon VI 6 Cs 132,9054 Ba 137,33 La 138,9 Hf 178,49 hafnium Ta 180,9479 tantalum W 183,85 tungsten Re 186,207 rhenium Os 190,2 osmium Ir 192,22 iridium Pt 195,09 platinum Au 196,9665 Hg 200,59 Tl 204,37 thallium Pb 207,2 lead Bi 208,9 bismuth Po 209 polonium At 210 astatine 222 radon VII 7 Fr 223 Ra 226,0 Ac 227 sea ​​anemone ×× Rf 261 rutherfordium Db 262 dubnium Sg 266 seaborgium Bh 269 bohrium Hs 269 Hassiy Mt 268 meitnerium Ds 271 Darmstadt Rg 272 Сn 285 Uut 113 284 ununtry Uug 289 ununquadium Uup 115 288 ununpentium Uuh 116 293 unungexium Uus 117 294 ununseptium Uuо 118 295 ununoctium La 138,9 lanthanum Ce 140,1 cerium Pr 140,9 praseodymium Nd 144,2 neodymium Pm 145 promethium Sm 150,4 samarium Eu 151,9 europium Gd 157,3 gadolinium Tb 158,9 terbium Dy 162,5 dysprosium Ho 164,9 holmium Er 167,3 erbium Tm 168,9 thulium Yb 173,0 ytterbium Lu 174,9 lutetium Ac 227 actinium Th 232,0 thorium Pa 231,0 protactinium U 238,0 Uranus Np 237 neptunium Pu 244 plutonium Am 243 americium Cm 247 curium Bk 247 berkelium Cf 251 californium Es 252 einsteinium Fm 257 fermium MD 258 mendelevium No 259 nobelium Lr 262 lawrencia

The discovery made by the Russian chemist Mendeleev played (by far) the most important role in the development of science, namely in the development of atomic-molecular science. This discovery made it possible to obtain the most understandable and easy-to-learn ideas about simple and complex chemical compounds. It is only thanks to the table that we have the concepts about the elements that we use in the modern world. In the twentieth century, the predictive role of the periodic system in assessing the chemical properties of transuranium elements, shown by the creator of the table, emerged.

Developed in the 19th century, Mendeleev's periodic table in the interests of the science of chemistry provided a ready-made systematization of the types of atoms for the development of PHYSICS in the 20th century (physics of the atom and the atomic nucleus). At the beginning of the twentieth century, physicists, through research, established that the atomic number (also known as atomic number) is also a measure of the electrical charge of the atomic nucleus of this element. And the number of the period (i.e., horizontal series) determines the number of electron shells of the atom. It also turned out that the number of the vertical row of the table determines the quantum structure of the outer shell of the element (thus, elements of the same row are obliged to have similar chemical properties).

The discovery of the Russian scientist marked a new era in the history of world science; this discovery allowed not only to make a huge leap in chemistry, but was also invaluable for a number of other areas of science. The periodic table provided a coherent system of information about the elements, based on it, it became possible to draw scientific conclusions, and even anticipate some discoveries.

Periodic Table One of the features of the periodic table is that the group (column in the table) has more significant expressions of the periodic trend than for periods or blocks. Nowadays, the theory of quantum mechanics and atomic structure explains the group essence of elements by the fact that they have the same electronic configurations of valence shells, and as a result, elements that are located within the same column have very similar (identical) features of the electronic configuration, with similar chemical properties. There is also a clear tendency for a stable change in properties as the atomic mass increases. It should be noted that in some areas of the periodic table (for example, in blocks D and F), horizontal similarities are more noticeable than vertical ones.

The periodic table contains groups that are assigned serial numbers from 1 to 18 (from left to right), according to the international group naming system. In the past, Roman numerals were used to identify groups. In America, there was a practice of placing after the Roman numeral, the letter “A” when the group is located in blocks S and P, or the letter “B” for groups located in block D. The identifiers used at that time are the same as the latter the number of modern indexes in our time (for example, the name IVB corresponds to elements of group 4 in our time, and IVA is the 14th group of elements). In European countries of that time, a similar system was used, but here, the letter “A” referred to groups up to 10, and the letter “B” - after 10 inclusive. But groups 8,9,10 had ID VIII, as one triple group. These group names ceased to exist after the new IUPAC notation system, which is still used today, came into force in 1988.

Many groups received unsystematic names of a herbal nature (for example, “alkaline earth metals”, or “halogens”, and other similar names). Groups 3 to 14 did not receive such names, due to the fact that they are less similar to each other and have less compliance with vertical patterns; they are usually called either by number or by the name of the first element of the group (titanium, cobalt, etc.) .

Chemical elements belonging to the same group of the periodic table show certain trends in electronegativity, atomic radius and ionization energy. In one group, from top to bottom, the radius of the atom increases as the energy levels are filled, the valence electrons of the element move away from the nucleus, while the ionization energy decreases and the bonds in the atom weaken, which simplifies the removal of electrons. Electronegativity also decreases, this is a consequence of the fact that the distance between the nucleus and valence electrons increases. But there are also exceptions to these patterns, for example, electronegativity increases, instead of decreasing, in group 11, in the direction from top to bottom. There is a line in the periodic table called “Period”.

Among the groups, there are those in which horizontal directions are more significant (unlike others in which vertical directions are more important), such groups include block F, in which lanthanides and actinides form two important horizontal sequences.

Elements show certain patterns in atomic radius, electronegativity, ionization energy, and electron affinity energy. Due to the fact that for each subsequent element the number of charged particles increases, and electrons are attracted to the nucleus, the atomic radius decreases from left to right, along with this the ionization energy increases, and as the bond in the atom increases, the difficulty of removing an electron increases. Metals located on the left side of the table are characterized by a lower electron affinity energy indicator, and accordingly, on the right side the electron affinity energy indicator is higher for non-metals (not counting the noble gases).

Different regions of the periodic table, depending on which shell of the atom the last electron is located on, and in view of the importance of the electron shell, are usually described as blocks.

The S-block includes the first two groups of elements (alkali and alkaline earth metals, hydrogen and helium).
The P-block includes the last six groups, from 13 to 18 (according to IUPAC, or according to the system adopted in America - from IIIA to VIIIA), this block also includes all metalloids.

Block - D, groups 3 to 12 (IUPAC, or IIIB to IIB in American), this block includes all transition metals.
Block - F, is usually placed outside the periodic table, and includes lanthanides and actinides.

Ether in the periodic table

The world ether is the substance of EVERY chemical element and, therefore, EVERY substance; it is the Absolute true matter as the Universal element-forming Essence.The world ether is the source and crown of the entire genuine Periodic Table, its beginning and end - the alpha and omega of the Periodic Table of Elements of Dmitry Ivanovich Mendeleev.

In ancient philosophy, ether (aithér-Greek), along with earth, water, air and fire, is one of the five elements of being (according to Aristotle) ​​- the fifth essence (quinta essentia - Latin), understood as the finest all-pervading matter. At the end of the 19th century, the hypothesis of a world ether (ME) filling all of the world’s space became widely circulated in scientific circles. It was understood as a weightless and elastic liquid that permeates all bodies. They tried to explain many physical phenomena and properties by the existence of the ether.

Preface.
Mendeleev had two fundamental scientific discoveries:
1 - Discovery of the Periodic Law in the substance of chemistry,
2 - Discovery of the relationship between the substance of chemistry and the substance of Ether, namely: particles of Ether form molecules, nuclei, electrons, etc., but do not participate in chemical reactions.
Ether is particles of matter ~ 10-100 meters in size (in fact, they are the “first bricks” of matter).

Data. Ether was in the original periodic table. The cell for Ether was located in the zero group with inert gases and in the zero row as the main system-forming factor for building the System of chemical elements. After Mendeleev's death, the table was distorted by removing Ether from it and eliminating the zero group, thereby hiding the fundamental discovery of conceptual significance.
In modern Ether tables: 1 - not visible, 2 - not guessable (due to the absence of a zero group).

Such purposeful forgery hinders the development of the progress of civilization.
Man-made disasters (eg Chernobyl and Fukushima) would have been avoided if adequate resources had been invested in a timely manner in the development of a genuine periodic table. Concealment of conceptual knowledge occurs at the global level to “lower” civilization.

Result. In schools and universities they teach a cropped periodic table.
Assessment of the situation. The periodic table without Ether is the same as humanity without children - you can live, but there will be no development and no future.
Summary. If the enemies of humanity hide knowledge, then our task is to reveal this knowledge.
Conclusion. The old periodic table has fewer elements and more foresight than the modern one.
Conclusion. A new level is possible only if the information state of society changes.

Bottom line. Returning to the true periodic table is no longer a scientific question, but a political question.

What was the main political meaning of Einstein's teaching? It consisted of cutting off humanity’s access to inexhaustible natural sources of energy by any means, which were opened up by the study of the properties of the world ether. If successful on this path, the global financial oligarchy would lose power in this world, especially in the light of the retrospective of those years: the Rockefellers made an unimaginable fortune, exceeding the budget of the United States, on oil speculation, and the loss of the role of oil that “black gold” occupied in in this world - the role of the lifeblood of the global economy - did not inspire them.

This did not inspire other oligarchs - the coal and steel kings. Thus, financial tycoon Morgan immediately stopped funding Nikola Tesla’s experiments when he came close to wireless energy transfer and extracting energy “out of nowhere” - from the world’s ether. After that, no one provided financial assistance to the owner of a huge number of technical solutions put into practice - the solidarity of financial tycoons is like that of thieves in law and a phenomenal nose for where the danger comes from. That is why against humanity and a sabotage was carried out under the name “Special Theory of Relativity”.

One of the first blows came to Dmitry Mendeleev’s table, in which ether was the first number; it was thoughts about ether that gave birth to Mendeleev’s brilliant insight - his periodic table of elements.

Chapter from the article: V.G. Rodionov. The place and role of the world ether in the true table of D.I. Mendeleev

6. Argumentum ad rem

What is now presented in schools and universities under the title “Periodic Table of Chemical Elements D.I. Mendeleev,” is an outright falsity.

The last time the real Periodic Table was published in an undistorted form was in 1906 in St. Petersburg (textbook “Fundamentals of Chemistry”, VIII edition). And only after 96 years of oblivion, the original Periodic Table rises for the first time from the ashes thanks to the publication of a dissertation in the journal ZhRFM of the Russian Physical Society.

After the sudden death of D.I. Mendeleev and the passing away of his faithful scientific colleagues in the Russian Physico-Chemical Society, the son of D.I. Mendeleev’s friend and colleague in the Society, Boris Nikolaevich Menshutkin, first raised his hand to Mendeleev’s immortal creation. Of course, Menshutkin did not act alone - he only carried out the order. After all, the new paradigm of relativism required the abandonment of the idea of ​​the world ether; and therefore this requirement was elevated to the rank of dogma, and the work of D.I. Mendeleev was falsified.

The main distortion of the Table is the transfer of the “zero group” of the Table to its end, to the right, and the introduction of the so-called. "periods". We emphasize that such (only at first glance, harmless) manipulation is logically explainable only as a conscious elimination of the main methodological link in Mendeleev’s discovery: the periodic system of elements at its beginning, source, i.e. in the upper left corner of the Table, must have a zero group and a zero row, where the element “X” is located (according to Mendeleev - “Newtonium”), - i.e. world broadcast.
Moreover, being the only system-forming element of the entire Table of Derived Elements, this element “X” is the argument of the entire Periodic Table. The transfer of the zero group of the Table to its end destroys the very idea of ​​this fundamental principle of the entire system of elements according to Mendeleev.

To confirm the above, we will give the floor to D.I. Mendeleev himself.

“... If the argon analogues do not give compounds at all, then it is obvious that it is impossible to include any of the groups of previously known elements, and for them a special group zero should be opened... This position of argon analogues in the zero group is a strictly logical consequence of understanding the periodic law, and therefore (the placement in group VIII is clearly incorrect) was accepted not only by me, but also by Braizner, Piccini and others... Now, when it has become beyond the slightest doubt that before that group I, in which hydrogen should be placed, there exists a zero group, whose representatives have atomic weights less than those of the elements of group I, it seems to me impossible to deny the existence of elements lighter than hydrogen.

Of these, let us first pay attention to the element of the first row of the 1st group. We denote it by “y”. It will obviously have the fundamental properties of argon gases... “Coronium”, with a density of about 0.2 relative to hydrogen; and it cannot in any way be the world ether.

This element “y”, however, is necessary in order to mentally get close to that most important, and therefore most rapidly moving element “x”, which, in my understanding, can be considered ether. I would like to tentatively call it “Newtonium” - in honor of the immortal Newton... The problem of gravitation and the problem of all energy (!!! - V. Rodionov) cannot be imagined to be really solved without a real understanding of the ether as a world medium that transmits energy over distances. A real understanding of the ether cannot be achieved by ignoring its chemistry and not considering it an elementary substance; elementary substances are now unthinkable without their subordination to periodic law” (“An Attempt at a Chemical Understanding of the World Ether.” 1905, p. 27).

“These elements, according to the magnitude of their atomic weights, took a precise place between the halides and the alkali metals, as Ramsay showed in 1900. From these elements it is necessary to form a special zero group, which was first recognized by Errere in Belgium in 1900. I consider it useful to add here that, directly judging by the inability to combine elements of group zero, analogues of argon should be placed before elements of group 1 and, in the spirit of the periodic system, expect a lower atomic weight for them than for alkali metals.

This is exactly what it turned out to be. And if so, then this circumstance, on the one hand, serves as confirmation of the correctness of the periodic principles, and on the other hand, clearly shows the relationship of argon analogs to other previously known elements. As a result, it is possible to apply the analyzed principles even more widely than before, and expect elements of the zero series with atomic weights much lower than those of hydrogen.

Thus, it can be shown that in the first row, first before hydrogen, there is an element of the zero group with an atomic weight of 0.4 (perhaps this is Yong’s coronium), and in the zero row, in the zero group, there is a limiting element with an negligibly small atomic weight, not capable of chemical interactions and, as a result, possessing extremely fast partial (gas) movement of its own.

These properties, perhaps, should be attributed to the atoms of the all-pervading (!!! - V. Rodionov) world ether. I indicated this idea in the preface to this publication and in a Russian journal article of 1902...” (“Fundamentals of Chemistry.” VIII ed., 1906, p. 613 et seq.)
1 , , ,

From the comments:

For chemistry, the modern periodic table of elements is sufficient.

The role of ether can be useful in nuclear reactions, but this is not very significant.
Taking into account the influence of ether is closest to the phenomena of isotope decay. However, this accounting is extremely complex and the presence of patterns is not accepted by all scientists.

The simplest proof of the presence of ether: The phenomenon of annihilation of a positron-electron pair and the emergence of this pair from a vacuum, as well as the impossibility of catching an electron at rest. Also the electromagnetic field and a complete analogy between photons in a vacuum and sound waves - phonons in crystals.

Ether is differentiated matter, so to speak, atoms in a disassembled state, or more correctly, elementary particles from which future atoms are formed. Therefore, it has no place in the periodic table, since the logic of constructing this system does not imply the inclusion of non-integral structures, which are the atoms themselves. Otherwise, it is possible to find a place for quarks, somewhere in the minus first period.
The ether itself has a more complex multi-level structure of manifestation in world existence than modern science knows about. As soon as she reveals the first secrets of this elusive ether, then new engines for all kinds of machines will be invented on completely new principles.
Indeed, Tesla was perhaps the only one who was close to solving the mystery of the so-called ether, but he was deliberately prevented from realizing his plans. So, to this day, the genius who will continue the work of the great inventor and tell us all what the mysterious ether actually is and on what pedestal it can be placed has not yet been born.

If you find the periodic table difficult to understand, you are not alone! Although it can be difficult to understand its principles, learning how to use it will help you when studying science. First, study the structure of the table and what information you can learn from it about each chemical element. Then you can begin to study the properties of each element. And finally, using the periodic table, you can determine the number of neutrons in an atom of a particular chemical element.

Steps

Part 1

Table structure

The periodic table, or periodic table of chemical elements, begins in the upper left corner and ends at the end of the last row of the table (lower right corner). The elements in the table are arranged from left to right in increasing order of their atomic number. The atomic number shows how many protons are contained in one atom. In addition, as the atomic number increases, the atomic mass also increases. Thus, by the location of an element in the periodic table, its atomic mass can be determined.

As you can see, each subsequent element contains one more proton than the element preceding it. This is obvious when you look at the atomic numbers. Atomic numbers increase by one as you move from left to right. Because elements are arranged in groups, some table cells are left empty.

• For example, the first row of the table contains hydrogen, which has atomic number 1, and helium, which has atomic number 2. However, they are located on opposite edges because they belong to different groups.

1. Learn about groups that contain elements with similar physical and chemical properties. The elements of each group are located in the corresponding vertical column. They are typically identified by the same color, which helps identify elements with similar physical and chemical properties and predict their behavior. All elements of a particular group have the same number of electrons in their outer shell.

   • Hydrogen can be classified as both alkali metals and halogens. In some tables it is indicated in both groups.
   • In most cases, the groups are numbered from 1 to 18, and the numbers are placed at the top or bottom of the table. Numbers can be specified in Roman (eg IA) or Arabic (eg 1A or 1) numerals.
   • When moving along a column from top to bottom, you are said to be “browsing a group.”

2. Find out why there are empty cells in the table. Elements are ordered not only according to their atomic number, but also by group (elements in the same group have similar physical and chemical properties). Thanks to this, it is easier to understand how a particular element behaves. However, as the atomic number increases, elements that fall into the corresponding group are not always found, so there are empty cells in the table.

   • For example, the first 3 rows have empty cells because transition metals are only found from atomic number 21.
   • Elements with atomic numbers 57 to 102 are classified as rare earth elements, and are usually placed in their own subgroup in the lower right corner of the table.

3. Each row of the table represents a period. All elements of the same period have the same number of atomic orbitals in which the electrons in the atoms are located. The number of orbitals corresponds to the period number. The table contains 7 rows, that is, 7 periods.

   • For example, atoms of elements of the first period have one orbital, and atoms of elements of the seventh period have 7 orbitals.
   • As a rule, periods are designated by numbers from 1 to 7 on the left of the table.
   • As you move along a line from left to right, you are said to be “scanning the period.”

4. Learn to distinguish between metals, metalloids and non-metals. You will better understand the properties of an element if you can determine what type it is. For convenience, in most tables metals, metalloids, and nonmetals are designated by different colors. Metals are on the left and non-metals are on the right side of the table. Metalloids are located between them.

   Part 2

   Element designations

   1. Each element is designated by one or two Latin letters. As a rule, the element symbol is shown in large letters in the center of the corresponding cell. A symbol is a shortened name for an element that is the same in most languages. Element symbols are commonly used when conducting experiments and working with chemical equations, so it is helpful to remember them.

      • Typically, element symbols are abbreviations of their Latin name, although for some, especially recently discovered elements, they are derived from the common name. For example, helium is represented by the symbol He, which is close to the common name in most languages. At the same time, iron is designated as Fe, which is an abbreviation of its Latin name.

   2. Pay attention to the full name of the element if it is given in the table. This element "name" is used in regular texts. For example, "helium" and "carbon" are names of elements. Usually, although not always, the full names of the elements are listed below their chemical symbol.

      • Sometimes the table does not indicate the names of the elements and only gives their chemical symbols.

   3. Find the atomic number. Typically, the atomic number of an element is located at the top of the corresponding cell, in the middle or in the corner. It may also appear under the element's symbol or name. Elements have atomic numbers from 1 to 118.

      • The atomic number is always an integer.

   4. Remember that the atomic number corresponds to the number of protons in an atom. All atoms of an element contain the same number of protons. Unlike electrons, the number of protons in the atoms of an element remains constant. Otherwise, you would get a different chemical element!

There are many repeating sequences in nature:

• Seasons;
• Times of Day;
• days of the week…

In the mid-19th century, D.I. Mendeleev noticed that the chemical properties of elements also have a certain sequence (they say that this idea came to him in a dream). The result of the scientist’s wonderful dreams was the Periodic Table of Chemical Elements, in which D.I. Mendeleev arranged chemical elements in order of increasing atomic mass. In the modern table, chemical elements are arranged in ascending order of the element's atomic number (the number of protons in the nucleus of an atom).

The atomic number is shown above the symbol of a chemical element, below the symbol is its atomic mass (the sum of protons and neutrons). Please note that the atomic mass of some elements is not a whole number! Remember isotopes! Atomic mass is the weighted average of all isotopes of an element found in nature under natural conditions.

Below the table are lanthanides and actinides.

Metals, non-metals, metalloids

Located in the Periodic Table to the left of a stepped diagonal line that begins with Boron (B) and ends with polonium (Po) (the exceptions are germanium (Ge) and antimony (Sb). It is easy to see that metals occupy most of the Periodic Table. Basic properties of metals : hard (except mercury); shiny; good electrical and thermal conductors; plastic; malleable; easily give up electrons.

The elements located to the right of the B-Po stepped diagonal are called non-metals. The properties of non-metals are exactly the opposite of those of metals: poor conductors of heat and electricity; fragile; non-malleable; non-plastic; usually accept electrons.

Metalloids

Between metals and non-metals there are semimetals(metalloids). They are characterized by the properties of both metals and non-metals. Semimetals have found their main application in industry in the production of semiconductors, without which not a single modern microcircuit or microprocessor is conceivable.

Periods and groups

As mentioned above, the periodic table consists of seven periods. In each period, the atomic numbers of elements increase from left to right.

The properties of elements change sequentially in periods: thus sodium (Na) and magnesium (Mg), located at the beginning of the third period, give up electrons (Na gives up one electron: 1s 2 2s 2 2p 6 3s 1 ; Mg gives up two electrons: 1s 2 2s 2 2p 6 3s 2). But chlorine (Cl), located at the end of the period, takes one element: 1s 2 2s 2 2p 6 3s 2 3p 5.

In groups, on the contrary, all elements have the same properties. For example, in group IA(1), all elements from lithium (Li) to francium (Fr) donate one electron. And all elements of group VIIA(17) take one element.

Some groups are so important that they have received special names. These groups are discussed below.

Group IA(1). Atoms of elements of this group have only one electron in their outer electron layer, so they easily give up one electron.

The most important alkali metals are sodium (Na) and potassium (K), since they play an important role in human life and are part of salts.

Electronic configurations:

• Li- 1s 2 2s 1 ;
• Na- 1s 2 2s 2 2p 6 3s 1 ;
• K- 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1

Group IIA(2). Atoms of elements of this group have two electrons in their outer electron layer, which they also give up during chemical reactions. The most important element is calcium (Ca) - the basis of bones and teeth.

Electronic configurations:

• Be- 1s 2 2s 2 ;
• Mg- 1s 2 2s 2 2p 6 3s 2 ;
• Ca- 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2

Group VIIA(17). Atoms of elements of this group usually receive one electron each, because There are five elements on the outer electronic layer and one electron is just missing from the “complete set”.

The most well-known elements of this group: chlorine (Cl) - is part of salt and bleach; Iodine (I) is an element that plays an important role in the activity of the human thyroid gland.

Electronic Configuration:

• F- 1s 2 2s 2 2p 5 ;
• Cl- 1s 2 2s 2 2p 6 3s 2 3p 5 ;
• Br- 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 5

Group VIII(18). Atoms of elements of this group have a fully “complete” outer electron layer. Therefore, they “don’t” need to accept electrons. And they “don’t want” to give them away. Hence, the elements of this group are very “reluctant” to enter into chemical reactions. For a long time it was believed that they do not react at all (hence the name “inert”, i.e. “inactive”). But chemist Neil Bartlett discovered that some of these gases can still react with other elements under certain conditions.

Electronic configurations:

• Ne- 1s 2 2s 2 2p 6 ;
• Ar- 1s 2 2s 2 2p 6 3s 2 3p 6 ;
• Kr- 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6

Valence elements in groups

It is easy to notice that within each group the elements are similar to each other in their valence electrons (electrons of s and p orbitals located on the outer energy level).

Alkali metals have 1 valence electron:

• Li- 1s 2 2s 1 ;
• Na- 1s 2 2s 2 2p 6 3s 1 ;
• K- 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1

Alkaline earth metals have 2 valence electrons:

• Be- 1s 2 2s 2 ;
• Mg- 1s 2 2s 2 2p 6 3s 2 ;
• Ca- 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2

Halogens have 7 valence electrons:

• F- 1s 2 2s 2 2p 5 ;
• Cl- 1s 2 2s 2 2p 6 3s 2 3p 5 ;
• Br- 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 5

Inert gases have 8 valence electrons:

• Ne- 1s 2 2s 2 2p 6 ;
• Ar- 1s 2 2s 2 2p 6 3s 2 3p 6 ;
• Kr- 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6

For more information, see the article Valency and the Table of Electronic Configurations of Atoms of Chemical Elements by Period.

Let us now turn our attention to the elements located in groups with symbols IN. They are located in the center of the periodic table and are called transition metals.

A distinctive feature of these elements is the presence in the atoms of electrons that fill d-orbitals:

1. Sc- 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 1 ;
2. Ti- 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 2

Separately from the main table are located lanthanides And actinides- these are the so-called internal transition metals. In the atoms of these elements, electrons fill f-orbitals:

1. Ce- 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 4d 10 5s 2 5p 6 4f 1 5d 1 6s 2 ;
2. Th- 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 4d 10 5s 2 5p 6 4f 14 5d 10 6s 2 6p 6 6d 2 7s 2

All chemical elements can be characterized depending on the structure of their atoms, as well as their position in the Periodic Table of D.I. Mendeleev. Typically, a chemical element is characterized according to the following plan:

• indicate the symbol of the chemical element, as well as its name;
• based on the position of the element in the Periodic Table D.I. Mendeleev indicate its ordinal, period number and group (type of subgroup) in which the element is located;
• based on the structure of the atom, indicate the nuclear charge, mass number, number of electrons, protons and neutrons in the atom;
• record the electronic configuration and indicate the valence electrons;
• sketch electron graphic formulas for valence electrons in the ground and excited (if possible) states;
• indicate the family of the element, as well as its type (metal or non-metal);
• indicate the formulas of higher oxides and hydroxides with a brief description of their properties;
• indicate the values ​​of the minimum and maximum oxidation states of a chemical element.

Characteristics of a chemical element using vanadium (V) as an example

Let's consider the characteristics of a chemical element using vanadium (V) as an example according to the plan described above:

1. V – vanadium.

2. Ordinal number – 23. The element is in the 4th period, in the V group, A (main) subgroup.

3. Z=23 (nuclear charge), M=51 (mass number), e=23 (number of electrons), p=23 (number of protons), n=51-23=28 (number of neutrons).

4. 23 V 1s 2 2s 2 2p 6 3s 2 3p 6 3d 3 4s 2 – electronic configuration, valence electrons 3d 3 4s 2.

5. Ground state

Excited state

6. d-element, metal.

7. Higher oxide - V 2 O 5 - exhibits amphoteric properties, with a predominance of acidic ones:

V 2 O 5 + 2NaOH = 2NaVO 3 + H 2 O

V 2 O 5 + H 2 SO 4 = (VO 2) 2 SO 4 + H 2 O (pH<3)

Vanadium forms hydroxides of the following composition: V(OH) 2, V(OH) 3, VO(OH) 2. V(OH) 2 and V(OH) 3 are characterized by basic properties (1, 2), and VO(OH) 2 has amphoteric properties (3, 4):

V(OH) 2 + H 2 SO 4 = VSO 4 + 2H 2 O (1)

2 V(OH) 3 + 3 H 2 SO 4 = V 2 (SO 4) 3 + 6 H 2 O (2)

VO(OH) 2 + H 2 SO 4 = VOSO 4 + 2 H 2 O (3)

4 VO(OH) 2 + 2KOH = K 2 + 5 H 2 O (4)

8. The minimum oxidation state is “+2”, the maximum is “+5”

Examples of problem solving

EXAMPLE 1

Exercise

Describe the chemical element phosphorus

Solution

1. P – phosphorus. 2. Ordinal number – 15. The element is in the 3rd period, in the V group, A (main) subgroup. 3. Z=15 (nuclear charge), M=31 (mass number), e=15 (number of electrons), p=15 (number of protons), n=31-15=16 (number of neutrons). 4. 15 P 1s 2 2s 2 2p 6 3s 2 3p 3 – electronic configuration, valence electrons 3s 2 3p 3. 5. Ground state Excited state 6. p-element, non-metal. 7. Higher oxide - P 2 O 5 - exhibits acidic properties: P 2 O 5 + 3Na 2 O = 2Na 3 PO 4 The hydroxide corresponding to the higher oxide - H 3 PO 4, exhibits acidic properties: H 3 PO 4 + 3NaOH = Na 3 PO 4 + 3H 2 O 8. The minimum oxidation state is “-3”, the maximum is “+5”

EXAMPLE 2

Exercise	Describe the chemical element potassium
Solution	1. K – potassium. 2. Ordinal number – 19. The element is in the 4th period, in group I, A (main) subgroup.