18 element of the periodic table is an impossible quest. Periodic system of Mendeleev

Periodic system of chemical elements (Mendeleev's table)- classification of chemical elements, establishing the dependence of various properties of elements on the charge of the atomic nucleus. The system is a graphical 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 image options have been proposed. periodic system(analytical curves, tables, geometric shapes etc.). In the modern version of the system, it is supposed to reduce the elements into a two-dimensional table, in which each column (group) determines the main physical Chemical properties, and the lines represent periods that are somewhat similar to each other.

Periodic system of chemical elements of D.I. Mendeleev

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 and molecular science. This discovery made it possible to obtain the most understandable, and easy to learn, ideas about simple and complex chemical compounds. Only thanks to the table we have those concepts about the elements that we use in 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, manifested itself.

Developed in the 19th century, Mendeleev's periodic table in the interests of the science of chemistry, gave a ready-made systematization of the types of atoms for the development of PHYSICS in the 20th century (physics of the atom and the nucleus of the atom). At the beginning of the twentieth century, physicists, through research, it was established that the serial number, (aka atomic), is also a measure of the electric charge of the atomic nucleus of this element. And the number of the period (ie the horizontal row) 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, the elements of the same row are due to the similarity of 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 gave a coherent system of information about the elements, based on it, it became possible to draw scientific conclusions, and even foresee some discoveries.

Periodic table One of the features of the periodic table of the Mendeleev 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 nature of elements by the fact that they have the same electronic configurations of valence shells, and as a result, elements that are within the same column have very similar (identical) features of the electronic configuration, with similar chemical properties. There is also a clear trend of 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 international system group names. In the old days, Roman numerals were used to identify groups. In America, the practice was to put after the Roman numeral, the letter "A" when the group is located in blocks S and P, or the letters "B" - for groups located in block D. The identifiers used at that time are the same as the last the number of modern pointers in our time (for example, the name IVB, corresponds to the elements of the 4th group in our time, and IVA is the 14th group of elements). AT 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 the identifier VIII as one triple group. These group names ceased to exist after the new IUPAC notation system, which is still in use today, came into force in 1988.

Many groups received non-systematic names of a traditional 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 correspondence to 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 periodic tables belonging to the same group 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 are removed from the nucleus, while the ionization energy decreases and the bonds in the atom weaken, which simplifies the removal of electrons. The electronegativity also decreases, this is a consequence of the fact that the distance between the nucleus and the valence electrons increases. But there are also exceptions to these patterns, for example, electronegativity increases, instead of decreasing, in group 11, from top to bottom. In the periodic table there is a line called "Period".

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

The elements show certain patterns in terms of atomic radius, electronegativity, ionization energy, and electron affinity energy. Due to the fact that for each next element the number of charged particles increases, and electrons are attracted to the nucleus, the atomic radius decreases in the direction from left to right, along with this, the ionization energy increases, with an increase in the bond in the atom, 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, for non-metals, this indicator is higher (not counting noble gases).

Different areas of the periodic table of Mendeleev, depending on which shell of the atom the last electron is on, and in view of the significance of the electron shell, it is customary to describe it as blocks.

The S-block includes the first two groups of elements, (alkali and alkaline earth metals, hydrogen and helium).
In the P-block, enter the pole recent 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, usually taken out of the periodic table, and includes lanthanides and actinides.

The Periodic Table (or PT, as we'll refer to it from time to time in this article), as well as the elements it contains, have traits that you may never have guessed. Here are ten facts, from creating a table to adding the last elements to it, that most people don't know.

10. Mendeleev was helped

The periodic table began to be used starting in 1869, when it was compiled by Dimitri Mendeleev, who was overgrown with a thick beard. Most people think that Mendeleev was the only one who worked on this table, and because of this he became the most brilliant chemist of the century. However, his efforts were assisted by several European scientists who made important contributions to the completion of this colossal set of elements.

Mendeleev is widely known as the father of the periodic table, but when he compiled it, not all elements of the table had already been discovered. How did this become possible? Scientists are famous for their madness...

9. Recently added items

Three elements were named after the cities or states where they were obtained, and oganesson was named after the Russian nuclear physicist Yuri Oganesyan for his contribution to obtaining this element.

8. What letter is not in the table?

They say that "one" is the number of lonely people. So, maybe we should call the letter "J" the letter of the lonely? But here's a fun fact: most boys born in the US in 2000 were given names beginning with that letter. Thus, this letter did not go unnoticed.

7. Synthesized elements

Do you think that 28 artificially created elements is a lot? Well, just take my word for it. They have been synthesized since 1937, and scientists continue to do so today. All these elements can be found in the table. Look at elements 95 to 118, all of these elements are absent from our planet and were synthesized in laboratories. The same applies to elements numbered 43, 61, 85 and 87.

6. 137th element

Are you tired of physics yet? You may be interested to know that the number 137 unites three important areas of physics: the theory of the speed of light, quantum mechanics and electromagnetism. Since the early 1900s, physicists have speculated that the number 137 may be the basis of the Great unified theory, which will include all three of the above areas. Admittedly, this sounds as incredible as the legends of UFOs and the Bermuda Triangle.

5. What can be said about the names?

Typically, element names fall into one of five main categories. The first is the names of famous scientists, the classic version is einsteinium. In addition, elements can be given names based on where they were first recorded, such as germanium, americium, gallium, etc. Planet names are used as an option. The element uranium was first discovered shortly after the discovery of the planet Uranus. Elements can have names associated with mythology, such as titanium, named after the ancient Greek titans, and thorium, named after the Norse thunder god (or stellar "avenger", whichever you prefer).

And finally, there are names that describe the properties of the elements. Argon comes from Greek word"argos", which means "lazy" or "slow". The name implies the assumption that this gas is not active. Bromine is another element whose name comes from a Greek word. "Bromos" means "stench" and this describes the smell of bromine quite accurately.

4. Was the creation of the table an "insight"

A lot of people can't even do regular solitaire, so this solitaire is impressive. What will happen next? Perhaps someone with the help of chess will revolutionize astrophysics or create a rocket capable of flying to the outskirts of the galaxy. It seems that this will not be unusual, given that Mendeleev managed to get such a brilliant result with just a deck of ordinary playing cards.

3. Unlucky inert gases

Even more strikingly, argon was not the only element that suffered this fate in the first place. In addition to argon, five other elements remained unclassified. This affected radon, neon, krypton, helium and xenon - and everyone denied their existence simply because Mendeleev could not find a place for them in the table. After several years of regrouping and reclassification, these elements (called inert gases) were still lucky enough to join a worthy club recognized as real.

2. Atomic love

Elements that "kiss" when folded are able to form stable connections. These elements have complementary electronic structures and they will combine with each other. And if it's not real love like Romeo and Juliet or Shrek and Fiona - then I don't know what love is.

1. Carbon rules

If the periodic table is compared to a party, then carbon is its main leader. And it seems that he is the only one who knows how to organize everything correctly. Well, among other things, it is the main element of all diamonds, so for all its importunity, it also shines!

Secret sections of the periodic table June 15th, 2018

Many people have heard about Dmitri Ivanovich Mendeleev and about the “Periodic law of changes in the properties of chemical elements by groups and series” discovered by him in the 19th century (1869) (the author’s name of the table is “Periodic system of elements by groups and series”).

The discovery of the table of periodic chemical elements was one of the important milestones in the history of the development of chemistry as a science. The pioneer of the table was the Russian scientist Dmitry Mendeleev. An extraordinary scientist with the broadest scientific horizons managed to combine all ideas about the nature of chemical elements into a single coherent concept.

Table opening history

By the middle of the 19th century, 63 chemical elements had been discovered, and scientists around the world have repeatedly attempted to combine all the existing elements into a single concept. The elements were proposed to be placed in ascending order of atomic mass and divided into groups according to the similarity of chemical properties.

In 1863, the chemist and musician John Alexander Newland proposed his theory, who proposed a layout of chemical elements similar to that discovered by Mendeleev, but the work of the scientist was not taken seriously by the scientific community due to the fact that the author was carried away by the search for harmony and the connection of music with chemistry.

In 1869, Mendeleev published his scheme of the periodic table in the journal of the Russian Chemical Society and sent out a notice of the discovery to the leading scientists of the world. In the future, the chemist repeatedly refined and improved the scheme until it acquired its familiar form.

The essence of Mendeleev's discovery is that with an increase in the atomic mass, the chemical properties of elements do not change monotonously, but periodically. After a certain number of elements with different properties, the properties begin to repeat. Thus, potassium is similar to sodium, fluorine is similar to chlorine, and gold is similar to silver and copper.

In 1871, Mendeleev finally united the ideas into the Periodic Law. Scientists predicted the discovery of several new chemical elements and described their chemical properties. Subsequently, the chemist's calculations were fully confirmed - gallium, scandium and germanium fully corresponded to the properties that Mendeleev attributed to them.

But not everything is so simple and there is something we do not know.

Few people know that D. I. Mendeleev was one of the first world-famous Russian scientists of the late 19th century, who defended in world science the idea of ​​ether as a universal substantial entity, who gave it fundamental scientific and applied significance in revealing the secrets of Being and to improve the economic life of the people.

There is an opinion that the periodic table of chemical elements officially taught in schools and universities is a fake. Mendeleev himself in his work entitled "An attempt at a chemical understanding of the world ether" gave a slightly different table.

The last time, in an undistorted form, the real Periodic Table saw the light in 1906 in St. Petersburg (textbook "Fundamentals of Chemistry", VIII edition).

The differences are visible: the zero group is moved to the 8th, and the element lighter than hydrogen, with which the table should begin and which is conventionally called Newtonium (ether), is generally excluded.

The same table is immortalized by the "BLOODY TYRANT" comrade. Stalin in St. Petersburg, Moskovsky Ave. 19. VNIIM them. D. I. Mendeleeva (All-Russian Research Institute of Metrology)

The monument-table The Periodic Table of Chemical Elements of D. I. Mendeleev was made with mosaics under the guidance of Professor of the Academy of Arts V. A. Frolov (architectural design of Krichevsky). The monument is based on a table from the last lifetime 8th edition (1906) of D. I. Mendeleev’s Fundamentals of Chemistry. Elements discovered during the life of D. I. Mendeleev are marked in red. Elements discovered from 1907 to 1934 , are marked in blue.

Why and how did it happen that we are so brazenly and openly lied to?

Place and role of the world ether in the true table of D. I. Mendeleev

Many people have heard about Dmitri Ivanovich Mendeleev and about the “Periodic law of changes in the properties of chemical elements by groups and series” discovered by him in the 19th century (1869) (the author’s name for the table is “The Periodic Table of Elements by Groups and Series”).

Many also heard that D.I. Mendeleev was the organizer and permanent leader (1869-1905) of the Russian public scientific association under the name "Russian Chemical Society" (since 1872 - "Russian Physico-Chemical Society"), which throughout its existence published the world-famous journal ZhRFKhO, until the liquidation of the Society and its journal by the Academy of Sciences of the USSR in 1930.
But few of those who know that D. I. Mendeleev was one of the last world-famous Russian scientists of the late 19th century, who defended in world science the idea of ​​ether as a universal substantial entity, who gave it fundamental scientific and applied significance in revealing secrets Being and to improve the economic life of people.

Even fewer of those who know that after the sudden (!!?) death of D. I. Mendeleev (01/27/1907), who was then recognized as an outstanding scientist by all scientific communities all over the world, with the exception of the St. Petersburg Academy of Sciences alone, his main discovery - the "Periodic Law" - was deliberately and everywhere falsified by world academic science.

And there are very few who know that all of the above is linked together by the thread of sacrificial service of the best representatives and bearers of the immortal Russian Physical Thought for the good of the peoples, for public benefit, despite the growing wave of irresponsibility in the upper strata of society of that time.

In essence, this dissertation is devoted to the comprehensive development of the last thesis, because in true science any neglect of essential factors always leads to false results.

The elements of the zero group begin each row of other elements, located on the left side of the Table, “... which is a strictly logical consequence of understanding the periodic law” - Mendeleev.

Particularly important and even exceptional in the sense of the periodic law, the place belongs to the element "x", - "Newtonius", - the world ether. And this special element should be located at the very beginning of the entire Table, in the so-called “zero group of the zero row”. Moreover, being a system-forming element (more precisely, a system-forming entity) of all elements of the Periodic Table, the world ether is a substantive argument for the entire variety of elements of the Periodic Table. The Table itself, in this regard, acts as a closed functional of this very argument.

Sources:

Element 115 of the periodic table - moscovium - is a superheavy synthetic element with the symbol Mc and atomic number 115. It was first obtained in 2003 by a joint team of Russian and American scientists at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. In December 2015, it was recognized as one of the four new elements by the Joint Working Group of International Scientific Organizations IUPAC/IUPAP. On November 28, 2016, it was officially named after the Moscow region where JINR is located.

Characteristic

115 element of the periodic table is extremely radioactive substance: Its most stable known isotope, moscovium-290 has a half-life of only 0.8 seconds. Scientists classify moscovium as an intransition metal, similar in a number of characteristics to bismuth. In the periodic table, it belongs to the transactinide elements of the p-block of the 7th period and is placed in group 15 as the heaviest pnictogen (an element of the nitrogen subgroup), although it has not been confirmed that it behaves like the heavier homologue of bismuth.

According to calculations, the element has some properties similar to lighter homologues: nitrogen, phosphorus, arsenic, antimony and bismuth. It shows several significant differences from them. To date, about 100 moscovium atoms have been synthesized, which have mass numbers from 287 to 290.

Physical properties

The valence electrons of element 115 of the periodic table muscovy are divided into three subshells: 7s (two electrons), 7p 1/2 (two electrons) and 7p 3/2 (one electron). The first two of them are relativistically stabilized and therefore behave like inert gases, while the latter are relativistically destabilized and can easily participate in chemical interactions. Thus, the primary ionization potential of moscovium should be about 5.58 eV. According to calculations, moscovium should be a dense metal due to its high atomic weight with a density of about 13.5 g/cm3.

Estimated design characteristics:

• Phase: solid.
• Melting point: 400°C (670°K, 750°F).
• Boiling point: 1100°C (1400°K, 2000°F).
• Specific heat of fusion: 5.90-5.98 kJ/mol.
• Specific heat of vaporization and condensation: 138 kJ/mol.

Chemical properties

The 115th element of the periodic table is the third in the 7p series of chemical elements and is the heaviest member of group 15 in the periodic table, located below bismuth. Chemical interaction of moscovium in aqueous solution due to the characteristics of Mc + and Mc 3+ ions. The former are presumably easily hydrolyzed and form ionic bonds with halogens, cyanides, and ammonia. Moscovium (I) hydroxide (McOH), carbonate (Mc 2 CO 3), oxalate (Mc 2 C 2 O 4) and fluoride (McF) must be soluble in water. The sulfide (Mc 2 S) must be insoluble. Chloride (McCl), bromide (McBr), iodide (McI) and thiocyanate (McSCN) are poorly soluble compounds.

Moscovium (III) fluoride (McF 3) and thiozonide (McS 3) are presumably insoluble in water (similar to the corresponding bismuth compounds). While chloride (III) (McCl 3), bromide (McBr 3) and iodide (McI 3) should be readily soluble and readily hydrolyzed to form oxohalides such as McOCl and McOBr (also similar to bismuth). Moscovium(I) and (III) oxides have similar oxidation states, and their relative stability is highly dependent on which elements they interact with.

Uncertainty

Due to the fact that the 115th element of the periodic table is synthesized by a few experimentally, its exact characteristics are problematic. Scientists have to focus on theoretical calculations and compare with more stable elements that are similar in properties.

In 2011, experiments were carried out to create isotopes of nihonium, flerovium and muscovy in reactions between "accelerators" (calcium-48) and "targets" (americium-243 and plutonium-244) to study their properties. However, the "targets" included impurities of lead and bismuth and, consequently, some isotopes of bismuth and polonium were obtained in nucleon transfer reactions, which complicated the experiment. Meanwhile, the data obtained will help scientists in the future to study in more detail the heavy homologues of bismuth and polonium, such as moscovium and livermorium.

Opening

The first successful synthesis of element 115 of the periodic table was teamwork Russian and American scientists in August 2003 at JINR in Dubna. The team led by nuclear physicist Yuri Oganesyan, in addition to domestic specialists, included colleagues from the Lawrence Livermore National Laboratory. On February 2, 2004, the researchers published information in the Physical Review that they bombarded americium-243 with calcium-48 ions at the U-400 cyclotron and obtained four atoms of a new substance (one 287 Mc nucleus and three 288 Mc nuclei). These atoms decay (decay) by emitting alpha particles to the element nihonium in about 100 milliseconds. Two heavier isotopes of moscovium, 289 Mc and 290 Mc, were discovered in 2009-2010.

Initially, IUPAC could not approve the discovery of the new element. Needed confirmation from other sources. Over the next few years, another evaluation of the later experiments was carried out, and once again the claim of the Dubna team for the discovery of the 115th element was put forward.

In August 2013, a team of researchers from the University of Lund and the Institute for Heavy Ions in Darmstadt (Germany) announced that they had repeated the 2004 experiment, confirming the results obtained in Dubna. Another confirmation was published by a team of scientists working at Berkeley in 2015. In December 2015, a joint working group IUPAC/IUPAP acknowledged the discovery of this element and gave priority to the discovery of the Russian-American team of researchers.

Name

Element 115 of the periodic table in 1979, according to the recommendation of IUPAC, it was decided to name "ununpentium" and designate it with the corresponding symbol UUP. Although the name has since been widely used for an undiscovered (but theoretically predicted) element, it has not caught on in the physics community. Most often, the substance was called that - element No. 115 or E115.

On December 30, 2015, the discovery of a new element was recognized by the International Union of Pure and Applied Chemistry. Under the new rules, discoverers have the right to propose their own name for a new substance. At first, it was supposed to name the 115th element of the periodic table "langevinium" in honor of the physicist Paul Langevin. Later, a team of scientists from Dubna, as an option, proposed the name "Muscovite" in honor of the Moscow region, where the discovery was made. In June 2016, IUPAC approved the initiative and on November 28, 2016 officially approved the name "moscovium".

Even at school, sitting in chemistry lessons, we all remember the table on the wall of a classroom or a chemical laboratory. This table contains the classification of all known to mankind chemical elements, those fundamental components that make up the Earth and the entire Universe. Then we could not even think that periodic table undoubtedly one of the greatest scientific discoveries which is the foundation of our modern knowledge about chemistry.

Periodic system of chemical elements of D. I. Mendeleev

At first glance, her idea looks deceptively simple: organize chemical elements in ascending order of the weight of their atoms. Moreover, in most cases it turns out that chemical and physical properties each element are similar to the element preceding it in the table. This pattern appears for all but a few of the very first elements, simply because they do not have elements in front of them that are similar in atomic weight to them. It is thanks to the discovery of such a property that we can place a linear sequence of elements in a table very reminiscent of a wall calendar, and thus combine great amount types of chemical elements in a clear and coherent way. Of course, today we use the concept of atomic number (the number of protons) in order to order the system of elements. This helped to solve the so-called technical problem of the "pair of permutations", but did not lead to a fundamental change in the appearance of the periodic table.

AT Mendeleev's periodic table all elements are ordered according to their atomic number, electronic configuration, and recurring chemical properties. The rows in a table are called periods, and the columns are called groups. The first table, dated 1869, contained only 60 elements, but now the table had to be enlarged to accommodate the 118 elements known to us today.

Periodic system of Mendeleev systematizes not only the elements, but also their most diverse properties. It is often enough for a chemist to have the Periodic Table in front of his eyes in order to correctly answer many questions (not only exams, but also scientific ones).

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Periodic Law

There are two formulations periodic law chemical elements: classical and modern.

Classical, as presented by its discoverer D.I. Mendeleev: properties simple bodies, as well as the forms and properties of the compounds of elements are in a periodic dependence on the values ​​of the atomic weights of the elements.

Modern: properties simple substances, as well as the properties and forms of compounds of elements are in a periodic dependence on the charge of the nucleus of atoms of elements (serial number).

A graphic representation of the periodic law is the periodic system of elements, which is a natural classification of chemical elements based on regular changes in the properties of elements from the charges of their atoms. The most common images of the periodic table of elements D.I. Mendeleev are short and long forms.

Groups and periods of the Periodic system

groups called the vertical rows in the periodic table. In groups, elements are combined according to the attribute the highest degree oxidation in oxides. Each group consists of the main and secondary subgroups. The main subgroups include elements of small periods and elements of large periods identical with it in properties. Side subgroups consist only of elements of large periods. The chemical properties of the elements of the main and secondary subgroups differ significantly.

Period call a horizontal row of elements arranged in ascending order of ordinal (atomic) numbers. There are seven periods in the periodic system: the first, second and third periods are called small, they contain 2, 8 and 8 elements, respectively; the remaining periods are called large: in the fourth and fifth periods there are 18 elements each, in the sixth - 32, and in the seventh (still incomplete) - 31 elements. Each period, except the first, begins with an alkali metal and ends with a noble gas.

The physical meaning of the serial number chemical element: the number of protons in the atomic nucleus and the number of electrons revolving around the atomic nucleus are equal to the ordinal number of the element.

Properties of the periodic table

Recall that groups call the vertical rows in the periodic system and the chemical properties of the elements of the main and secondary subgroups differ significantly.

The properties of elements in subgroups naturally change from top to bottom:

• intensify metallic properties and weaken non-metallic;
• the atomic radius increases;
• the strength of the bases and anoxic acids formed by the element increases;
• electronegativity drops.

All elements, except helium, neon and argon, form oxygen compounds, there are only eight forms of oxygen compounds. In the periodic system, they are often represented by general formulas located under each group in ascending order of the oxidation state of the elements: R 2 O, RO, R 2 O 3, RO 2, R 2 O 5, RO 3, R 2 O 7, RO 4, where the symbol R denotes an element of this group. Formulas for higher oxides apply to all elements of the group, except in exceptional cases when the elements do not show an oxidation state equal to the group number (for example, fluorine).

Oxides of composition R 2 O show strong basic properties, and their basicity increases with increasing serial number, oxides of composition RO (with the exception of BeO) show basic properties. Oxides of the composition RO 2 , R 2 O 5 , RO 3 , R 2 O 7 exhibit acidic properties, and their acidity increases with increasing serial number.

Elements of the main subgroups, starting from group IV, form gaseous hydrogen compounds. There are four forms of such compounds. They are placed under the elements of the main subgroups and are represented by general formulas in the sequence RH 4 , RH 3 , RH 2 , RH.

RH 4 compounds are neutral; RH 3 - weakly basic; RH 2 - slightly acidic; RH is strongly acidic.

Recall that period call a horizontal row of elements arranged in ascending order of ordinal (atomic) numbers.

Within the period with an increase in the serial number of the element:

• electronegativity increases;
• metallic properties decrease, non-metallic ones increase;
• atomic radius falls.

Elements of the periodic table

Alkaline and alkaline earth elements

These include elements from the first and second groups of the periodic table. alkali metals from the first group - soft metals, silvery, well cut with a knife. All of them have a single electron in the outer shell and perfectly react. alkaline earth metals from the second group also have a silver tint. Two electrons are placed at the outer level, and, accordingly, these metals are less willing to interact with other elements. Compared to alkali metals, alkaline earth metals melt and boil at higher temperatures.

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Lanthanides (rare earth elements) and actinides

Lanthanides is a group of elements originally found in rare minerals; hence their name "rare earth" elements. Subsequently, it turned out that these elements are not as rare as they thought at first, and therefore the name lanthanides was given to the rare earth elements. lanthanides and actinides occupy two blocks, which are located under the main table of elements. Both groups include metals; all lanthanides (with the exception of promethium) are non-radioactive; actinides, on the other hand, are radioactive.

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Halogens and noble gases

The halogens and noble gases are grouped into groups 17 and 18 of the periodic table. Halogens are non-metallic elements, they all have seven electrons in their outer shell. AT noble gases all electrons are in the outer shell, thus hardly participate in the formation of compounds. These gases are called "noble" because they rarely react with other elements; i.e. refer to members of the noble caste who have traditionally shunned other people in society.

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transition metals

transition metals occupy groups 3-12 in the periodic table. Most of them are dense, solid, with good electrical and thermal conductivity. Their valence electrons (through which they connect with other elements) are in several electron shells.

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Metalloids

Metalloids occupy groups 13-16 of the periodic table. Metalloids such as boron, germanium, and silicon are semiconductors and are used to make computer chips and circuit boards.

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Post-transition metals

The elements called post-transition metals, belong to groups 13-15 of the periodic table. Unlike metals, they do not have a shine, but have a matte finish. Compared to transition metals, post-transition metals are softer, have more low temperature melting and boiling, higher electronegativity. Their valence electrons, with which they attach other elements, are located only on the outer electron shell. Elements of the group of post-transition metals have much more high temperature boiling than metalloids.

And now consolidate your knowledge by watching a video about the periodic table and more.

Great, the first step on the path to knowledge has been taken. Now you are more or less guided by the periodic table and this will be very useful to you, because the Periodic Table is the foundation on which this amazing science stands.