The first periodic table of Mendeleev. Periodic system of chemical elements of D.I. Mendeleev

How to use the periodic table? For an uninitiated person, reading the periodic table is the same as looking at the ancient runes of elves for a dwarf. And the periodic table, by the way, if used correctly, can tell a lot about the world. In addition to serving you in the exam, it is also simply indispensable for solving a huge number of chemical and physical problems. But how to read it? Fortunately, today everyone can learn this art. In this article we will tell you how to understand the periodic table.

The periodic system of chemical elements (Mendeleev's table) is a classification of chemical elements that establishes the dependence of various properties of elements on the charge of the atomic nucleus.

History of the creation of the Table

Dmitri Ivanovich Mendeleev was not a simple chemist, if someone thinks so. He was a chemist, physicist, geologist, metrologist, ecologist, economist, oilman, aeronaut, instrument maker and teacher. During his life, the scientist managed to conduct a lot of fundamental research in various fields of knowledge. For example, it is widely believed that it was Mendeleev who calculated the ideal strength of vodka - 40 degrees. We do not know how Mendeleev treated vodka, but it is known for sure that his dissertation on the topic “Discourse on the combination of alcohol with water” had nothing to do with vodka and considered alcohol concentrations from 70 degrees. With all the merits of the scientist, the discovery of the periodic law of chemical elements - one of the fundamental laws of nature, brought him the widest fame.

There is a legend according to which the scientist dreamed of the periodic system, after which he only had to finalize the idea that had appeared. But, if everything were so simple .. This version of the creation of the periodic table, apparently, is nothing more than a legend. When asked how the table was opened, Dmitry Ivanovich himself answered: “ I’ve been thinking about it for maybe twenty years, and you think: I sat and suddenly ... it’s ready. ”

In the middle of the nineteenth century, attempts to streamline the known chemical elements (63 elements were known) were simultaneously undertaken by several scientists. For example, in 1862 Alexandre Émile Chancourtois placed the elements along a helix and noted the cyclical repetition of chemical properties. Chemist and musician John Alexander Newlands proposed his version of the periodic table in 1866. An interesting fact is that in the arrangement of the elements the scientist tried to discover some mystical musical harmony. Among other attempts was the attempt of Mendeleev, which was crowned with success.

In 1869, the first scheme of the table was published, and the day of March 1, 1869 is considered the day of the discovery of the periodic law. The essence of Mendeleev's discovery was that the properties of elements with increasing atomic mass do not change monotonously, but periodically. The first version of the table contained only 63 elements, but Mendeleev made a number of very non-standard decisions. So, he guessed to leave a place in the table for yet undiscovered elements, and also changed the atomic masses of some elements. The fundamental correctness of the law derived by Mendeleev was confirmed very soon, after the discovery of gallium, scandium and germanium, the existence of which was predicted by scientists.

Modern view of the periodic table

Below is the table itself.

Today, instead of atomic weight (atomic mass), the concept of atomic number (the number of protons in the nucleus) is used to order elements. The table contains 120 elements, which are arranged from left to right in ascending order of atomic number (number of protons)

The columns of the table are so-called groups, and the rows are periods. There are 18 groups and 8 periods in the table.

• The metallic properties of elements decrease when moving along the period from left to right, and increase in the opposite direction.
• The dimensions of atoms decrease as they move from left to right along the periods.
• When moving from top to bottom in the group, the reducing metallic properties increase.
• Oxidizing and non-metallic properties increase along the period from left to right. I.

What do we learn about the element from the table? For example, let's take the third element in the table - lithium, and consider it in detail.

First of all, we see the symbol of the element itself and its name under it. In the upper left corner is the atomic number of the element, in the order in which the element is located in the table. The atomic number, as already mentioned, is equal to the number of protons in the nucleus. The number of positive protons is usually equal to the number of negative electrons in an atom (with the exception of isotopes).

The atomic mass is indicated under the atomic number (in this version of the table). If we round the atomic mass to the nearest integer, we get the so-called mass number. The difference between the mass number and the atomic number gives the number of neutrons in the nucleus. Thus, the number of neutrons in a helium nucleus is two, and in lithium - four.

So our course "Mendeleev's Table for Dummies" has ended. In conclusion, we invite you to watch a thematic video, and we hope that the question of how to use the periodic table of Mendeleev has become clearer to you. We remind you that learning a new subject is always more effective not alone, but with the help of an experienced mentor. That is why, you should never forget about those who will gladly share their knowledge and experience with you.

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 variants of the representation of the periodic system (analytical curves, tables, geometric figures, etc.) have been proposed. 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 and chemical properties, and the rows represent periods similar to each other to a certain extent.

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 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, manifested itself.

Developed in the 19th century, the periodic table of Mendeleev 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, 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 essence of elements by the fact that they have the same electronic configurations of valence shells, and as a result, the 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 the international group naming system. In the old days, Roman numerals were used to identify groups. In America there was a practice 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). 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 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 have 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 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 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).
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, usually taken out of the periodic table, and includes lanthanides and actinides.

The Periodic Table (or PT, as we will refer to it from time to time in this article), as well as the elements that make up it, 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 the production of 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 could be the basis of a Grand Unified Theory that would 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, for example, there is titanium, named after the ancient Greek titans, and thorium, named after the Scandinavian thunder god (or star "avenger", depending on which you prefer).

And finally, there are names that describe the properties of the elements. Argon comes from the 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 true 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!

If the periodic table seems difficult for you to understand, you are not alone! Although it can be difficult to understand its principles, learning to work with it will help in the study of natural sciences. To get started, study the structure of the table and what information can be learned from it about each chemical element. Then you can start exploring 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

The periodic table, or periodic table of chemical elements, begins at the top left and ends at the end of the last line of the table (bottom right). The elements in the table are arranged from left to right in ascending order of their atomic number. The atomic number tells you how many protons are in one atom. In addition, as the atomic number increases, so does the atomic mass. Thus, by the location of an element in the periodic table, you can determine its atomic mass.

As you can see, each next 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. Since the elements are arranged in groups, some table cells remain 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 on opposite ends because they belong to different groups.

1. Learn about groups that include elements with similar physical and chemical properties. The elements of each group are located in the corresponding vertical column. As a rule, they are indicated by the same color, which helps to 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 the outer shell.

   • Hydrogen can be attributed both to the group of alkali metals and to the group of 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 given in Roman (eg IA) or Arabic (eg 1A or 1) numerals.
   • When moving along the column from top to bottom, they say that you are "browsing the group".

2. Find out why there are empty cells in the table. Elements are ordered not only according to their atomic number, but also according to groups (elements of the same group have similar physical and chemical properties). This makes it easier to understand how an 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, since transition metals are found only from atomic number 21.
   • Elements with atomic numbers from 57 to 102 belong to the rare earth elements, and they are usually placed in a separate 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 electrons are located in atoms. The number of orbitals corresponds to the period number. The table contains 7 rows, that is, 7 periods.

   • For example, the atoms of the elements of the first period have one orbital, and the atoms of the elements of the seventh period have 7 orbitals.
   • As a rule, periods are indicated 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 through a 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 belongs to. For convenience, in most tables, metals, metalloids and non-metals are indicated 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 an abbreviated name for an element that is the same in most languages. When doing experiments and working with chemical equations, the symbols of the elements are commonly used, so it is useful to remember them.

      • Typically, element symbols are shorthand for their Latin name, although for some, especially recently discovered elements, they are derived from the common name. For example, helium is denoted 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 "name" of the element is used in normal texts. For example, "helium" and "carbon" are the names of the elements. Usually, though not always, the full names of the elements are given under their chemical symbol.

      • Sometimes the names of the elements are not indicated in the table and only their chemical symbols are given.

   3. Find the atomic number. Usually the atomic number of an element is located at the top of the corresponding cell, in the middle or in the corner. It can also appear below the symbol or element 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, another chemical element would have turned out!

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

Element 115 of the periodic table is extremely radioactive: its most stable known isotope, moscovium-290, has a half-life of just 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 period 7 and is placed in group 15 as the heaviest pnictogen (a nitrogen subgroup element), although it has not been confirmed to behave like the heavier bismuth homologue.

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. The chemical interaction of moscovium in an aqueous solution is determined by the characteristics of the 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 easily 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 depends to a large extent 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 moscovium 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 the joint work of 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 publication 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 IUPAC/IUPAP working group 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".