The International Union of Pure and Applied Chemistry (IUPAC) has announced which names it considers most appropriate for the four new elements of the periodic table. It is recommended to name one of them in honor of the Russian physicist, academician Yuri Oganesyan. Shortly before this, the KSh correspondent met with Yuri Tsolakovich and did a long interview with him. But IUPAC is asking scientists not to comment until November 8, when the new names will be officially announced. Regardless of whose name appears in the periodic table, we can state: Russia has become one of the leaders in the transuranium race, which has been going on for more than half a century.

Yuri Oganesyan. Specialist in the field of nuclear physics, academician of the Russian Academy of Sciences, scientific director of the Laboratory of Nuclear Reactions at JINR, head of the Department of Nuclear Physics at the University of Dubna. As a student of Georgy Flerov, he participated in the synthesis of rutherfordium, dubnium, seaborgium, bohrium, etc. Among the world-class discoveries is the so-called cold fusion of nuclei, which turned out to be an extremely useful tool for creating new elements.

In the lower lines of the periodic table you can easily find uranium, its atomic number is 92. All subsequent elements do not exist in nature now and were discovered as a result of very complex experiments.
American physicists Glenn Seaborg and Edwin MacMillan were the first to create a new element. This is how plutonium was born in 1940. Later, together with other scientists, Seaborg synthesized americium, curium, berkelium... The very fact of man-made expansion of the periodic table is in some sense comparable to a flight into space.

The leading countries of the world have entered the race to create super-heavy nuclei (if desired, an analogy could be drawn with the lunar race, but here our country is more likely to win). In the USSR, the first transuranium element was synthesized in 1964 by scientists from the Joint Institute for Nuclear Research (JINR) in Dubna, Moscow Region. It was the 104th element - called rutherfordium. The project was led by one of the founders of JINR, Georgiy Flerov. His name is also included in the table: flerovium, 114. And the 105th element was called dubnium.

Yuri Oganesyan was a student of Flerov and participated in the synthesis of rutherfordium, and then dubnium, seaborgium, bohrium... The successes of our physicists made Russia a leader in the transuranium race along with the USA, Germany, Japan (and perhaps the first among equals).

The new elements in question - 113, 115, 117, 118 - were synthesized in 2002–2009 at JINR at the U-400 cyclotron. In accelerators of this type, beams of heavy charged particles - protons and ions - are accelerated using a high-frequency electric field, in order to then collide with each other or with a target and study the products of their decay.

All experiments were carried out by international collaborations almost simultaneously in different countries. For example, scientists from the Japanese RIKEN Institute synthesized the 113th element independently of the others. As a result, the opening priority was given to them.

A new chemical element is first given a temporary name, derived from the Latin numeral. For example, ununoctium is "one hundred and eighteenth". Then the scientific team - the author of the discovery - sends its proposals to IUPAC. The commission is considering the arguments for and against. In particular, she recommends adhering to the following rules: “Newly discovered elements may be named: (a) after a mythological character or concept (including an astronomical object); (b) by the name of a mineral or similar substance; (c) by the name of a locality or geographic area; (d) in accordance with the properties of the element or (e) by the name of the scientist..."

The names must be easy to pronounce in most known languages ​​and contain information that allows the element to be unambiguously classified. For example, all transurans have two-letter symbols and end in “-iy” if they are metals: rutherfordium, dubnium, seaborgium, bohrium...

Whether the two new elements (115 and 118) will receive “Russian” names will become clear in November. But there are still many experiments ahead, because according to the hypothesis of islands of stability, there are heavier elements that can exist for a relatively long time. They are even trying to find such elements in nature, but it would be more accurate if Oganesyan synthesizes them at an accelerator.

Dossier on new elements

Serial number: 113

How and by whom it was discovered: a target of americium-243 was bombarded with calcium-48 ions and ununpentium isotopes were obtained, which decayed into isotopes of element 113. Synthesized in 2003.

Opening priority: Institute of Physical and Chemical Research (RIKEN), Japan.

Current name: ununtry.

Intended properties: heavy fusible metal.

Suggested name: nihonium (Nh). This element was the first to be discovered in Asia in general and Japan in particular. “Nihonii” is one of two options for the country’s self-name. "Nihon" translates to "land of the rising sun."

Serial number: 115

How and by whom it was discovered: americium-243 target was bombarded with calcium-48 ions. Synthesized in 2003. Priority in discovery: collaboration consisting of JINR (Russia), Livermore National Laboratory (USA) and Oak Ridge National Laboratory (USA).

Current name: ununpentium.

Intended properties: metal similar to bismuth.

Suggested name: moscovium (Moscovium, Mc). IUPAC approved the name “Moscow” in honor of the Moscow region, where Dubna and JINR are located. Thus, this Russian city can leave its mark on the periodic table for the second time: dubnium has long been officially called the 105th element.

Serial number: 117

How and by whom it was discovered: a berkelium-249 target was bombarded with calcium-48 ions. Synthesized in 2009. Priority for discovery: JINR, Livermore, Oak Ridge.

Current name: ununseptium.

Intended properties: formally refers to halogens like iodine. The actual properties have not yet been determined. Most likely, it combines the characteristics of a metal and a non-metal.

Suggested name: Tennessine (Ts). In recognition of the contributions of the State of Tennessee, USA, including Oak Ridge National Laboratory, Vanderbilt University, and the University of Tennessee, to the synthesis of transuraniums.

Serial number: 118

How and by whom it was discovered: a californium-249 target was bombarded with calcium-48. Synthesized in 2002. Priority in discovery: JINR, Livermore.

Current name: ununoctium.

Intended properties: According to its chemical characteristics, it belongs to inert gases.

Suggested name: oganesson (Oganesson, Og). In honor of the scientific director of the Laboratory of Nuclear Reactions of JINR Yuri Oganesyan, who made a great contribution to the study of superheavy elements. Public discussion of possible names will last until November 8, after which the commission will make a final decision.

on "Schrodinger's Cat"

Chemical elements.

Achievements and prospects

The definition that D.I. Mendeleev gave to chemical science still remains correct and accurate: “Chemistry is the study of elements and chemical compounds.” Chemical elements are the foundation of all chemistry, since all chemical compounds known today (there are currently more than 14 million of them), as well as all those that will someday be obtained, are composed of them.

Many quite rightly perceive the main part of the periodic table as a list of elementary “bricks” from which objects in the surrounding world are built. However, chemical elements should not be considered only as “building materials” for constructing molecules, since in their pure form they have merits no less than millions of compounds obtained from them, and are extremely widely used in the modern world (see more about this: Chemical elements in everyday life. "Chemistry", 1998, No. 42).

Respecting strict terminology, we note that a chemical element is a Latin symbol in the periodic table or a specific atom, but subsequent research can be obtained and carried out not with a chemical element, but only with a so-called simple substance consisting of atoms of the same type. In English-language literature it is simpler: both are called in one word - element. Therefore, we will further use the Russian analogue of this word in the broad sense.

Summing up the results of the century, let us first of all consider how the periodic table was filled with new elements in the current century. By the end of the previous century, D.I. Mendeleev’s table contained about 80 elements. Beginning of the 20th century was marked by the award of the Nobel Prize to W. Ramsay for the discovery of inert gases (1904); however, such an event was not always celebrated so solemnly. The production of only two more elements - radium and polonium - was noted in the same way (M. Sklodowska-Curie, Nobel Prize 1911).

In 1927, rhenium was obtained. This was a unique milestone in the history of the discovery of new elements, since rhenium was the last stable chemical element found in nature. Then everything became much more complicated, since all subsequent elements could be obtained exclusively using nuclear reactions.

It took quite a lot of time to fill the four empty cells in the middle of the table to uranium (see about this: Errors and misconceptions in the history of chemistry. "Chemistry", 1999, No. 8). Technetium - element No. 43 - was obtained in 1937 by prolonged irradiation of a molybdenum plate with heavy hydrogen (deuterium) nuclei. Element No. 87 - francium - was discovered in 1939 in the radioactive decay products of natural actinium. Element number 85 - astatine - was obtained in 1940 by bombarding bismuth with helium nuclei. Element No. 61, promethium, was isolated in 1945 from the fission products of uranium. Then, with the help of nuclear fusion reactions, the 7th period of the table began to be gradually filled with elements following uranium. The last chemical element to receive a name was No. 109. Elements from No. 110 onwards are designated only by atomic numbers.

Now we can already say that the twentieth century is ending no less solemnly than it began. In December 1998, a new element, No. 114, was obtained in Dubna by irradiating a plutonium isotope with a beam of accelerated calcium ions. If we sum up the number of protons of two interacting nuclei - plutonium and calcium, we get 94 + 20 = 114. This corresponds to element number 114. However, the resulting nucleus, whose mass is 244 + 48 = 292, turned out to be unstable. It emits three neutrons and forms an isotope. Preliminary calculations showed that element No. 114, as well as the so far unattainable elements No. 126 and No. 164, should fall into the so-called islands of stability. Regarding element No. 114, this was confirmed. Its lifetime is more than 0.5 minutes, which is a very large value for such a superheavy atom. In 1999, element No. 118 was obtained at the Berkeley Laboratory (USA) by bombarding lead with krypton ions. Its lifetime is milliseconds. When it decays, it forms a new unstable element No. 116, which quickly turns into the more stable element No. 114.

So, today the periodic table ends with the 118th element. Experiments on the synthesis of new elements are extremely labor-intensive and quite lengthy. The fact is that, passing through the electron shells of atoms, projectile nuclei are slowed down and lose energy. In addition, the nucleus formed during fusion most often disintegrates into two lighter nuclei. Only in rare cases does it emit several neutrons (as, for example, when obtaining element No. 114) and form the desired heavy nucleus. Despite the difficulties, experiments aimed at synthesizing new elements continue.

Considering all the wealth of chemical elements accumulated to date, let's try to sum up the century. Let's conduct a kind of competition between all the chemical elements known today and try to determine which of them ended up in the 20th century. the most significant. In other words, we will note only those elements that most contributed to raising the level of civilization and the development of progress.

There are only two obvious leaders. The first one is Uranus, who created a completely new scientific discipline - nuclear physics and provided humanity with enormous reserves of energy. Many will likely find such leadership controversial. Uranus gave humanity the expectation of the grim consequences of the use of nuclear weapons, the accident of nuclear power plants (NPPs) and the problem of nuclear waste disposal.

All these fears are well founded, but let’s look at the issue in more detail.

As for the threat of the use of nuclear weapons, humanity constantly keeps this problem in its field of vision. All issues related to a complete ban on the production and use of such weapons will inevitably have to be resolved in the future. More complex and controversial is the issue of the use of nuclear energy for peaceful purposes. The Chernobyl disaster on April 26, 1986 led to the fact that all people’s hearts clench with anxiety at the words “radiation” and “exposure.” Confidence in nuclear power has been shaken around the world.

Shouldn't nuclear power plants be abandoned altogether? At first it seemed that this would happen. Many countries have begun to reconsider the need to build new stations. The referendums held showed that the majority of people believe that it is necessary to abandon the use of nuclear energy. However, a calm, sober analysis of everything that happened gradually led to different conclusions. In terms of accident rates, nuclear power plants are practically in last place among all modern sources that produce electricity in large quantities. Moreover, the number of deaths during the operation of nuclear power plants is somewhat lower than even in the food and textile industries.

This picture has not changed even when taking into account the consequences of the Chernobyl accident, the largest in the history of the development of nuclear energy. It occurred primarily due to a gross violation of operating rules: the reactor contained an unacceptably small number of cadmium rods, which inhibited the reaction. In addition, the station did not have a protective cap to prevent the release of radioactive substances into the atmosphere. As a result, one of the worst options was realized. Nevertheless, the release of radioactive substances into the atmosphere did not exceed 3.5% of their total amount accumulated in the reactor. Of course, no one thinks that this can be reconciled. Nuclear power plant safety control systems were subsequently significantly revised. Major research and development efforts are currently aimed at increasing their accident-free operation. The reactor control must be reliably blocked both from criminal negligence and from possible malicious plans of terrorists. In addition, all newly constructed stations will be equipped with protective caps to prevent the possibility of radioactive substances entering the environment.

No one is going to downplay the dangers of nuclear reactors. However, whether we like it or not, all the accumulated experience in the development of civilization inevitably leads to a certain conclusion.

Never in the history of mankind has there been a case when it refused the achievements of progress only because they pose a certain danger. Explosions of steam boilers, railway and plane crashes, car accidents, and electric shocks have not led to humanity banning the use of these technical means. As a result, the intensity of work aimed at increasing their safety only increased. Bans took place only for various types of weapons. The same is the case with nuclear energy.

Will new nuclear power plants really be built? Yes, this is inevitable, since already more than a quarter of the electricity consumed by large cities (Moscow, St. Petersburg) is produced by nuclear power plants (in Western countries this figure is higher). Humanity will no longer be able to refuse this new type of energy. With reliably organized operation, nuclear power plants undoubtedly benefit in comparison with thermal stations that consume trains with hydrocarbon fuels and pollute the atmosphere with combustion products of coal and oil.
Hydroelectric power stations turn forests and arable lands into wetlands and disrupt the natural biorhythm of all life on a vast territory. Nuclear power plants are incomparably more convenient to operate. They can be located in places remote from coal deposits and without sources of hydroelectric power. Nuclear fuel is changed no more than once every six months. Fuel consumption can be assessed using the following indicator. The fission of 1 g of uranium isotopes releases the same amount of energy as the combustion of 2800 kg of hydrocarbon fuel. In other words, 1 kg of nuclear fuel replaces a train of coal.

At the same time, the world's uranium reserves contain millions of times more accumulated energy than the energy resources of existing gas, oil and coal reserves. Nuclear fuel will last for tens of thousands of years, given the ever-increasing need for energy sources. At the same time, hydrocarbon raw materials can be used much more efficiently for the synthesis of various organic products.

The question immediately arises of what to do with spent nuclear fuel waste. Many people have probably heard about the problems of burying such waste. Intensive scientific work is being carried out to solve this problem (humanity usually realizes it with some delay). One of the promising ways is the construction of nuclear reactors that reproduce fuel. In conventional nuclear reactors, the uranium isotope 238 U is a kind of ballast; the main reaction takes place with the participation of the isotope 235 U, which, by the way, is very small in natural uranium (less than 1%). However, low-active 238 U, being in a certain amount in a nuclear reactor, can capture part of the released neutrons, ultimately forming plutonium 239 Pu, which itself is a nuclear fuel, no less effective than 235 U.

The schemes of many nuclear transformations are simple and clear. Two indices are placed before the symbol of a chemical element. The upper one indicates the mass of the nucleus, i.e. the sum of protons and neutrons, the lower one indicates the number of protons, i.e. the positive charge of the nucleus. When writing a reaction equation, you must follow a simple rule - the total amounts of charges of protons and electrons in both sides of the equation must be equal. In addition, you should know one of the simple equations of nuclear chemistry - a neutron can decay into a proton and an electron: n 0 = p + + e – .

This is what the scheme for converting 238 U into 239 Pu looks like, thanks to which in the future it will be possible to use completely all reserves of natural uranium as fuel:

The first equation shows that a neutron is captured by a uranium nucleus and an extremely unstable uranium isotope is formed. The intermediate stage is the formation and decay of an unstable isotope of neptunium. In the second and third equations, a neutron is converted into a proton (which remains in the nucleus) and an electron, which is released in the form b - radiation. This is the traditional name for the flow of electrons emitted by a radioactive substance. As a result, a very stable isotope of plutonium is formed with a half-life of 24 thousand years, which can be used as nuclear fuel in the same reactors.

So, the problem of waste destruction is postponed for a while, but is not completely removed, however, it is, in principle, solvable.

When the reactor operates, the uranium nucleus decays to form radioactive isotopes of various elements with a lower mass. The main isotopes are cobalt 60 Co, strontium 90 Sr and cesium 137 Cs, promethium 147 Pm, technetium 99 Tc. Some of them have already found application, for example, in the treatment of tumors (cobalt guns), for pre-sowing stimulation of seeds, and even in forensics. Another area of ​​application is the sterilization of food and medical products, since the isotopes emitted by these b - and g - radiation does not lead to the appearance of radioactivity in the irradiated substance.

It is very attractive to be able to create based on such b -emitters are sources of electricity. Under the influence b -rays (i.e., the flow of electrons) in semiconductor substances such as silicon or germanium, a potential difference arises. This makes it possible to create, for example, based on the 147 Pm isotope, long-term sources of electric current that operate without recharging for many years.

A nuclear reactor can be used in the same way as a kind of reaction flask for the directed synthesis of isotopes of various elements, in addition to those formed during spontaneous decay. Various substances are placed in special capsules in a nuclear reactor, where they are intensively irradiated with neutrons, resulting in the formation of the corresponding isotopes. Obtained in this way g -active isotopes of thulium and ytterbium, as well as technetium isotopes formed in reactors, are used to create compact mobile installations that replace bulky X-ray machines. They can be used not only for diagnostics for medical purposes, but also for the needs of technology for the purpose of flaw detection of various structures and equipment.

Thus, radioactive waste contains quite noticeable reserves of unspent energy, and methods for its extraction will be further improved.

Summarize. Uranium occupies a prominent place among all other elements. Thanks to him, in the 20th century, a new scientific direction was created - nuclear physics - and a practically inexhaustible source of energy was discovered.

The second element that claims an exceptional role in the twentieth century is silicon. Proving its significance will not be difficult, since it is not associated with various dark fears, as is the case with uranium. In the second half of the century, bulky vacuum tube electronic computers were replaced by compact computers. The brain of the computer - the processor - is made of ultra-pure silicon crystal. The semiconductor properties of silicon made it possible to create miniature ultra-fast computing devices based on it, which formed the basis of all modern computers. Of course, a lot of modern technologies and various substances are used in the production of computers, but since we are talking only about chemical elements, the exclusive role of silicon is obvious.

It is clear that we are now in the initial stage of a powerfully developing process - the hurricane proliferation of computers in literally all areas of human activity. This is not just a stage of technological progress. The observed result is more impressive than in the case of uranium, since there is not only the development of new technical means, but also a change in the lifestyle and way of thinking of mankind.

Computers are entering homes with determination and energy, captivating every family member, especially the younger generation. Before our eyes, to some extent, the process of restructuring human psychology is taking place. Computers are gradually replacing televisions and VCRs, since most people devote most of their free time to them. They open up amazing opportunities for creativity and leisure.

The capabilities of computers are unusually great, and therefore they become indispensable in the work of scientists, writers, poets, musicians, designers, chess players, and photographers. They have completely captivated fans of puzzles and strategy games, as well as those who want to learn foreign languages ​​and lovers of home cooking. World Information Network Internet literally doubled the capabilities of computers. Any information and reference sources, literary and encyclopedic publications have become available; but an exceptional opportunity arose for communication between people connected by common interests. As a result, most people feel a sense of affection for their computer comparable to the love they have for their pets.

It is impossible not to note the additional advantages of silicon based on its semiconductor properties. We mentioned one of them a little earlier. This is an opportunity to transform b - radiation into electricity. The second very valuable property is realized in solar panels - the ability to convert daylight into electrical energy. It is currently used in low-power devices such as calculators and to power spacecraft. In the near future, more powerful solar panels will find widespread use in everyday life.

Thus, silicon is partially invading even the energy sector, where uranium is the leader. So, the second winner of our competition is silicon, which ushered in the era of semiconductors and computer technology.

Competition between chemical elements can be arranged according to other parameters. Let's pose the question differently. Which chemical element (let me remind you that we are not considering chemical compounds) is consumed by humanity the most? Obviously, the one that produces the most. In order for the competition to be fair, we will remove the effect of differences in atomic masses of elements, we will count them individually, that is, we will consider production volumes expressed in moles.

Below are, in ascending order, the average annual production (in moles) of some of the most commonly consumed elements (1980s levels):

W – 1.4 10 7 ; U – 2 10 8 ; Si – 2,8 10 8 ; Mo – 6 10 8 ; Ti – 6,3 10 8 ;
Mg – 8 10 9 ; Cu – 1,2 10 11 ; Al – 4,4 10 11 ; O – 1 10 12 ; Cl – 1,2 10 12 ;
S – 1,7 10 12 ; N – 5,1 10 12 ; Fe – 1,2 10 13 ; H – 3 10 13 ; C – 3,3 10 13 ,

Carbon took a dominant place thanks to coal and petroleum coke, consumed primarily by metallurgy. Diamonds and graphite make up only a small portion of all carbon produced and mined. Hydrogen quite naturally took second place, since its areas of application are extremely diverse: metallurgy, oil refining, chemical and glass production, as well as rocketry. Iron took an honorable third place in our competition, despite its rather high atomic mass.

Let me remind you that we are comparing the production of elements expressed in moles. If a comparison were made in mass terms, then iron would prove to be the undisputed leader. It has been known to mankind since ancient times, and its role in the development of progress has constantly increased. Figuratively speaking, the above-mentioned uranium and silicon can be compared to the new stars that flared up in the sky of the twentieth century, while iron is a reliable luminary that illuminates the entire path of civilization for many centuries. Iron is the core of all modern industry, and it can be assumed that this role will continue into the 21st century.

It is interesting to compare the series obtained above with the prevalence of elements on the globe. Here are the eight most common elements (in order of increasing molar abundance): Na, Fe,H, Mg, Ca,Al, Si, O. Obviously, the pattern is different. Nature failed to impose its rules of the game on humanity. We consume most of all not what is available in maximum quantity, but what is dictated by the needs of progress.

The capabilities of chemical elements are far from being completely exhausted. I wonder which of them will be the most significant in the 21st century? It is hardly possible to predict this. Let us leave this issue to be decided and summed up by those who will celebrate 2101.

Let's return again to the periodic table - a wonderful catalog of chemical elements. Recently, it is more often depicted in the form of an expanded table. This configuration is incomparably more visual and convenient. The horizontal rows, called periods, became longer. In this version, there are no longer eight groups of elements, as before, but eighteen. The term “subgroups” disappears, only groups remain. All elements of the same type (they are marked with individual background coloring) are arranged compactly. Lanthanides and actinides, as before, are placed on separate lines.

Now let's try to look into the future. How will the periodic table be filled in further? The table shown above ends with the actinide lawrencium - No. 103. Let us consider the lower part of the table in more detail, introducing elements discovered in recent years.

The chemical properties of element No. 114, obtained in 1998, can be roughly predicted by its position in the periodic table. This is an intransition element located in the carbon group, and its properties should resemble the lead located above it. However, the chemical properties of the new element are not available for direct study - the element is fixed in the amount of several atoms and is short-lived.

The last element received today - No. 118 - has all seven electronic levels completely filled. Therefore, it is quite natural that it is in the group of inert gases - radon is located above it. Thus, the 7th period of the periodic table is completed. Spectacular finale of the century!

Throughout the twentieth century. Humanity has largely filled this seventh period, and it now extends from element No. 87 - France - to the newly synthesized element No. 118 (some elements in this period are not yet obtained, such as No. 113, 115 and 117).

The moment is coming, in a certain sense, solemn. From element No. 119 in the periodic table a new, 8th period will begin. This event will probably brighten the beginning of the next century. The scheme for the gradual completion of electronic shells is clear in general terms. Everything will be played according to an already known system: at a certain moment, f-elements corresponding to lanthanides, and then - analogues d-elements called transitional. The most interesting thing is that the elements of the 8th period will also begin to fill in a new one, which does not exist for all elements received today g-level. So, they will appear g-elements that have no analogues in the periodic table known to us today. There is reason to believe that they will precede f-elements.

A careful examination of the periodic table reveals a certain harmony in it, which is not immediately noticeable. It is thanks to this harmony that the system has some predictive power. Let's confirm this with several examples.

Let us pose the question: how many expected g-elements in the 8th period? A simple calculation allows you to find out. First, remember that electrons are located at certain levels. The number of possible levels for each element corresponds to the period number. Electronic levels are divided into sublevels called orbitals and designated by letters of the Latin alphabet s, p, d, f. Each new sublevel can appear only at a set moment when the atomic number reaches a certain value. Each sublevel (or, in other words, each orbital) can accommodate no more than two electrons. s- Each element can have only one orbital; it has either one or two electrons. R-There can be three orbitals, therefore, the maximum possible number of electrons in them is six. Why R-can there be only three orbitals? This is determined by the laws of quantum mechanics. In our conversation we will not focus on this. d-There can only be five orbitals, which means 10 electrons.

Group names of elements are given in accordance with the names of orbitals. Elements that are filled with electrons s- orbitals are called s-elements, if filled R-orbitals, then this R-elements, and so on. All this is clearly visible in the table, where for each type of element the corresponding background color is given. Thus, in each period of the table there are two s-elements, six each p- elements and ten d-elements. Check this simple pattern in the table ( d-elements appear for the first time only in the 4th period).

You probably noticed that the number of possible orbitals when going from s- To p- And d- orbitals has a simple pattern. This is a series of odd numbers: 1, 3, 5. How many possible numbers do you think there are? f-orbitals? Logic dictates seven. This is true, and they can accommodate a maximum of 14 electrons. Means, f-elements in one period can only be 14. This is exactly the number of lanthanides in the table. Actinoids too f-elements, and there are also 14 of them. Now the main question: how many can there be g-orbitals? Let us mentally extend the series of numbers: 1, 3, 5, 7. Therefore, g-orbitals are nine, and the number of possible g-elements – 18.

So, we have answered the question posed above. All this can be confirmed experimentally only in the distant future. What will be the number of the very first one? g- element? It is not yet possible to answer unequivocally, since the order in which the electronic levels are filled out may not be the same as in the upper part of the table. By analogy with the moment at which they appear f-elements, we can assume that this will be element No. 122.

Let's try to solve another issue. How many elements will there be in the 8th period? Since the addition of each electron corresponds to the appearance of a new element, you simply need to add up the maximum number of electrons in all orbitals from s before g: 2 + 6 + 10 + 14 + 18 = 50. For a long time this was assumed, but computer calculations show that in the 8th period there will be not 50, but 46 elements.

So, the 8th period, which, as we believe, will begin to fill in the 21st century, will extend from element No. 119 to No. 164. However, the discovery of a new element is an expected thing, but not always predictable, and therefore one must be prepared for the fact that element No. 119 will be received even before this article falls into the hands of the reader, which will add even greater solemnity to the moment of the advent of the new century.

A careful examination of the periodic table allows us to note another simple pattern. R-Elements first appear in the 2nd period, d-elements – in the 4th, f-elements – in the 6th. The result is a series of even numbers: 2, 4, 6. This pattern is determined by the rules for filling electron shells. Now you should understand why g- the elements will appear, as mentioned above, in the 8th period. A simple continuation of a series of even numbers! There are longer-range forecasts, but they are based on fairly complex calculations. For example, it is shown that in the 9th period there will be only 8 elements, as in the 2nd and 3rd, which is somewhat unexpected.

Very interesting, is there theoretically the last element of the periodic table? Modern calculations cannot yet answer this question, so it has not yet been resolved by science.

We have gone quite far in our forecasts, perhaps even into the 22nd century, which, however, is quite understandable. Trying to glance into the distant future is a completely natural desire for every person, especially at the moment when not only the century, but also the millennium is changing.

M.M.Levitsky

The modern material and technical base of production is approximately 90% made up of only two types of materials: metals and ceramics. About 600 million tons of metal are produced annually in the world - over 150 kg. for every inhabitant of the planet. About the same amount of ceramics is produced along with bricks. The production of metal costs hundreds and thousands of times more, the production of ceramics is much easier technically and more economically profitable, and, most importantly, ceramics in many cases turns out to be a more suitable structural material compared to metal.

Using new chemical elements - zirconium, titanium, boron, germanium, chromium, molybdenum, tungsten, etc. Recently, fire-resistant, heat-resistant, chemical-resistant, high-hardness ceramics, as well as ceramics with a set of specified electrophysical properties, have been synthesized.

Superhard material - hexanite-R, as one of the crystalline varieties of boron nitride, with a melting point of over 3200 0 C and a hardness close to the hardness of diamond, has a record high viscosity, i.e. it is not as fragile as all other ceramic materials. Thus, one of the most difficult scientific and technical problems of the century has been solved: until now, all structural ceramics had a common drawback - fragility, but now a step has been taken to overcome it.

The great advantage of technical ceramics of the new composition is that machine parts are made from it by pressing powders to obtain finished products of given shapes and sizes.

Today we can name another unique property of ceramics - superconductivity at temperatures above the boiling point of nitrogen; this property opens up unprecedented scope for scientific and technological progress, for the creation of super-powerful engines and electric generators, the creation of magnetic levitation transport, the development of super-powerful electromagnetic accelerators for launching payloads into space, etc.

The chemistry of organosilicon compounds has made it possible to create large-scale production of a wide variety of polymers with fire-retardant, water-repellent, electrical insulation and other valuable properties. These polymers are indispensable in a number of energy and aviation industries.

Fluorocarbons are tetrafluoromethane, hexafluoroethane and their derivatives, where the carbon atom carries a weak positive charge, and the fluorine atom with the electronegativity inherent in fluorine has a weak negative charge. As a result, fluorocarbons have exceptional stability even in very aggressive environments of acids and alkalis, special surface activity, and the ability to absorb oxygen and peroxides. Therefore, they are used as a material for prostheses of human internal organs.

Question 57. Chemical processes and vital processes. Catalysts and enzymes.

Intensive recent research has been aimed at elucidating both the material composition of plant and animal tissues and the chemical processes occurring in the body. The idea of ​​the leading role of enzymes, first proposed by the great French naturalist Louis Pasteur (1822-1895), remains fundamental to this day. At the same time, static biochemistry studies the molecular composition and structure of tissue of living and nonliving organisms.

Dynamic biochemistry was born at the turn of the 18th and 19th centuries, when they began to distinguish between the processes of respiration and fermentation, assimilation and dissimilation as certain transformations of substances.

Fermentation research forms the main subject fermentology - core branch of knowledge about life processes. Over the course of a very long history of research, the process of biocatalysis has been considered from two different points of view. One of them, conventionally called chemical, was adhered to by J. Liebig and M. Berthelot, and the other, biological, was adhered to by L. Pasteur.

In the chemical concept, all catalysis was reduced to ordinary chemical catalysis. Despite the simplified approach, important provisions were established within the concept: an analogy between biocatalysis and catalysis, between enzymes and catalysts; the presence of two unequal components in enzymes - active centers and carriers; conclusion about the important role of transition metal ions and active centers of many enzymes; conclusion about the extension of the laws of chemical kinetics to biocatalysis; reduction in some cases of biocatalysis to catalysis by inorganic agents.

At the beginning of its development, the biological concept did not have such extensive experimental evidence. Its main support was the works of L. Pasteur and, in particular, his direct observations of the activity of lactic acid bacteria, which made it possible to identify fermentation and the ability of microorganisms to obtain the energy they need for life through fermentation. From his observations, Pasteur concluded that enzymes had a special level of material organization. However, all his arguments, if not refuted, were at least relegated to the background after the discovery of extracellular fermentation, and Pasteur’s position was declared vitalistic.

However, over time, Pasteur's concept won out. The promise of this concept is evidenced by modern evolutionary catalysis and molecular biology. On the one hand, it has been established that the composition and structure of biopolymer molecules represent a single set for all living beings, which is quite accessible for studying physical and chemical properties - the same physical and chemical laws govern both abiogenic processes and life processes. On the other hand, the exceptional specificity of living things has been proven, manifested not only in the highest levels of cell organization, but also in the behavior of fragments of living systems at the molecular level, which reflects the patterns of other levels. The specificity of the molecular level of living things lies in the significant difference in the principles of action of catalysts and enzymes, in the difference in the mechanisms of formation of polymers and biopolymers, the structure of which is determined only by the genetic code, and, finally, in its unusual fact: many chemical oxidation-reduction reactions in a living cell can occur without direct contact between reacting molecules. This means that chemical transformations can occur in living systems that have not been detected in the inanimate world.

In a nuclear reactor with neutrons of several MeV, reactions can take place (n,p) and(n,a) . In this way, the four most important radioactive isotopes 14 C, 32 P, 35 S and 3 H are formed by the reactions:

14 N(n,p) 14 C; 32 S(n,p) 32 P; 35 Cl(n,a) 35 S; 6 Li(n,a) 3 H

In all of these cases, a radioactive isotope of another chemical element is formed from a target element, and thus it becomes possible to isolate these isotopes without carrier or with specified radioactivity.

To obtain radionuclides, in addition to nuclear reactors, other sources of bombarding particles and gamma quanta, the operation of which is based on the occurrence of various nuclear reactions, are widely used. Powerful streams of charged particles are obtained using accelerators(electrostatic, linear and cyclotrons, etc.), in which charged particles are accelerated under the influence of constant or alternating fields. In electrostatic and linear accelerators, particles are accelerated by a single electric field; in cyclotrons, a magnetic field also acts simultaneously with the electric one.

Rice. Synchrophasotron

To produce high-energy neutrons, neutron generators are used, which use nuclear reactions under the influence of charged particles, most often deuterons. (d, n) or protons (p, n).

Using accelerators mainly receive radionuclides with different Z.

With boosters the progress of recent years is related in the synthesis of new chemical elements. Thus, by irradiation in a cyclotron with alpha particles with an energy of 41 MeV and a beam density of 6 × 10 12 particles/s einsteinia the first 17 atoms were obtained mendelevium:

Subsequently, this gave impetus to the intensive development of the method of accelerating multiply charged ions. By bombarding uranium-238 in a cyclotron with carbon ions, californium was obtained:

U(C6+,6n)Cf

However, light projectiles - carbon or oxygen ions - made it possible to advance only to elements 104-10. Over time, to synthesize heavier nuclei, isotopes with serial numbers 106 and 107 were obtained by irradiating stable isotopes of lead and bismuth with chromium ions:

Pb(Cr,3n)Sg

209 83 B(Cr,2n)Bh

In 1985, the alpha-active element 108-hassium (Hs) was obtained in Dubna. irradiation with Cf neon-22:

Cf(Ne+4n)Hs

In the same year, in the laboratory of G. Seaborg, they synthesized 109 and 110 elements by irradiation of uranium-235 with argon nuclei 40.

The synthesis of further elements was carried out by bombarding U, curium-248, Es with Ca nuclei.

The synthesis of element 114 was carried out in 1999 in Dubna by fusion of calcium-48 and plutonium-244 nuclei. The new, superheavy nucleus cools, emitting 3-4 neutrons, and then decays by emitting alpha particles to element 110.

To synthesize element 116, a fusion reaction of curium-248 with calcium –48 was carried out. In 2000, the formation and decay of element 116 was recorded three times. Then, after about 0.05 s, the nucleus of element 116 decays to element 114, followed by a chain of alpha decays to element 110, which decays spontaneously.

The half-lives of the spontaneously decaying new elements synthesized were several microseconds. It would seem that continuing the synthesis of heavier elements becomes pointless, since their lifetime and yield are too short. At the same time, the discovered half-lives of these elements turned out to be much longer than expected. Therefore, it can be assumed that with a certain combination of protons and neutrons, stable nuclei with half-lives of many thousands of years should be obtained.

And so, obtaining isotopes that are not found in nature is a purely technical task, since theoretically the question is clear. You need to take a target, irradiate it with a stream of bombarding particles with the appropriate energy, and quickly isolate the desired isotope. However, choosing a suitable target and bombarding particles is not so easy.

Earlier in 2011, IUPAC recognized the JINR collaboration with LLNL (USA) as having priority in the discovery of elements 114 and 116, which were named: element 114 - Flerovium, Fl; 116 element ― Livermorium, Lv.

Flerovium - in honor of the Laboratory of Nuclear Reactions named after. G.N. Flerov JINR, which is a recognized leader in the field of synthesis of superheavy elements, and its founder, the outstanding physicist Academician G.N. Flerov (1913−1990) - the author of the discovery of a new type of radioactivity of spontaneous fission of heavy nuclei, the founder of a number of new scientific directions, the founder and the first director of FLNR JINR, which now bears his name.

Livermorium - in honor of the Livermore National Laboratory. Lawrence and its location - the city of Livermore (California, USA). Livermore scientists have been participating in experiments on the synthesis of new elements conducted in Dubna for more than 20 years.

In general, the IUPAC decision is recognition of the outstanding contribution of JINR scientists to the discovery of the “island of stability” of superheavy elements, which is one of the most important achievements of modern nuclear physics.