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The first element in the periodic table. MY adept travel notes. Valence elements in groups

The nineteenth century in the history of mankind is a century in which many sciences were reformed, including chemistry. It was at this time that Mendeleev's periodic system appeared, and with it the periodic law. It was he who became the basis of modern chemistry. Periodic system D.I.Mendeleev is a systematization of elements, which establishes the dependence of chemical and physical properties from the structure and charge of the atom of the substance.

History

The beginning of the periodical was laid by the book "Correlation of properties with the atomic weight of elements", written in the third quarter of the 17th century. It reflected the basic concepts of the well-known chemical elements(at that time there were only 63 of them). In addition, for many of them the atomic masses were determined incorrectly. This greatly interfered with the discovery of D.I. Mendeleev.

Dmitry Ivanovich began his work by comparing the properties of elements. First of all, he took up chlorine and potassium, and only then moved on to work with alkali metals. Armed with special cards on which chemical elements were depicted, he repeatedly tried to assemble this "mosaic": he laid it out on his table in search of the necessary combinations and coincidences.

After much effort, Dmitry Ivanovich nevertheless found the pattern he was looking for, and lined up the elements in periodic rows. As a result, having received empty cells between the elements, the scientist realized that not all chemical elements are known to Russian researchers, and that it was he who should give this world the knowledge in the field of chemistry that had not yet been given by his predecessors.

Everyone knows the myth that the periodic table appeared to Mendeleev in a dream, and he gathered the elements into a single system from memory. This is, roughly speaking, a lie. The fact is that Dmitry Ivanovich worked on his work for a long time and with concentration, and it was very exhausting him. While working on the system of elements, Mendeleev once fell asleep. When he woke up, he realized that he had not finished the table, and rather continued filling in empty cells. His acquaintance, a certain Inostrantsev, a university teacher, decided that Mendeleev had dreamed the table in a dream and spread this rumor among his students. This is how this hypothesis appeared.

Notoriety

Chemical elements of Mendeleev is a reflection of the periodic law created by Dmitry Ivanovich in the third quarter of the 19th century (1869). It was in 1869 at a meeting of the Russian chemical community that Mendeleev's notice about the creation of a certain structure was read out. And in the same year the book "Fundamentals of Chemistry" was published, in which Mendeleev's periodic table of chemical elements was first published. And in the book “ Natural system elements and its use to indicate the qualities of undiscovered elements "D. I. Mendeleev first mentioned the concept of" periodic law ".

Structure and rules for placing elements

The first steps in the creation of the periodic law were taken by Dmitry Ivanovich back in 1869-1871, at that time he worked hard to establish the dependence of the properties of these elements on the mass of their atom. The modern version is a two-dimensional table of elements.

The position of an element in the table has a certain chemical and physical meaning. By the location of an element in the table, you can find out what valency it has, determine other chemical features. Dmitry Ivanovich tried to establish a connection between elements, both similar in properties and different.

He based the classification of the chemical elements known at that time on the valence and atomic mass. Comparing the relative properties of elements, Mendeleev tried to find a pattern that would combine all known chemical elements into one system. Having arranged them, based on the increase in atomic masses, he nevertheless achieved periodicity in each of the rows.

Further development of the system

The periodic table, which appeared in 1969, has been revised more than once. With the advent of noble gases in the 1930s, it turned out to reveal the newest dependence of elements - not on mass, but on the serial number. Later it was possible to establish the number of protons in atomic nuclei, and it turned out that it coincides with the ordinal number of the element. Scientists of the 20th century studied the electronic one.It turned out that it also affects the frequency. This greatly changed the idea of the properties of elements. This point was reflected in later editions of Mendeleev's periodic table. Each new discovery of the properties and features of the elements fit organically into the table.

Characteristics of the periodic table of Mendeleev

The periodic table is divided into periods (7 lines arranged horizontally), which, in turn, are subdivided into large and small. The period begins with an alkali metal, and ends with an element with non-metallic properties.
Dmitry Ivanovich's table is vertically divided into groups (8 columns). Each of them in the periodic system consists of two subgroups, namely, the main and the secondary. After long disputes, at the suggestion of DI Mendeleev and his colleague U. Ramzai, it was decided to introduce the so-called zero group. It includes inert gases (neon, helium, argon, radon, xenon, krypton). In 1911, the scientist F. Soddy was proposed to place indistinguishable elements, the so-called isotopes, in the periodic table - separate cells were allocated for them.

Despite the fidelity and accuracy of the periodic system, the scientific community did not want to recognize this discovery for a long time. Many great scientists ridiculed the activities of D.I. Mendeleev and believed that it was impossible to predict the properties of an element that had not yet been discovered. But after the alleged chemical elements were discovered (and these were, for example, scandium, gallium and germanium), Mendeleev's system and his periodic law became the science of chemistry.

Table in modern times

Mendeleev's Periodic Table of Elements is the basis of most of the chemical and physical discoveries associated with atomic-molecular science. The modern concept of an element was formed precisely thanks to the great scientist. The emergence of Mendeleev's periodic table brought about dramatic changes in the concept of various compounds and simple substances. The creation of the periodic system by scientists had a huge impact on the development of chemistry and all sciences adjacent to it.

If you find the periodic table difficult to understand, you are not alone! While it can be difficult to understand its principles, knowing how to work with it will help you in your science studies. First, 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 item. And finally, using the periodic table, you can determine the number of neutrons in an atom of a particular chemical element.

Steps

Part 1

Table structure

The periodic table, or the periodic table of chemical elements, begins in the upper left corner and ends at the end of the last line of the table (in the lower right corner). Elements in the table are arranged from left to right in ascending order of their atomic number. The atomic number shows how many protons there are in one atom. In addition, with an increase in the atomic number, the atomic mass also increases. 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 proton more 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 items are arranged in groups, some cells in the table remain blank.
- For example, the first row of the table contains hydrogen, which has atomic number 1, and helium, which has atomic number 2. However, they are located on opposite edges, since they belong to different groups.
Learn about groups that include elements with similar physical and chemical properties. The elements of each group are arranged in a corresponding vertical column. They are usually represented by a single color, which helps identify elements with similar physical and chemical properties and predict their behavior. All elements of a particular group have the same number of electrons on 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, groups are numbered from 1 to 18, and numbers are placed at the top or bottom of the table. Numbers can be specified in Roman (for example, IA) or Arabic (for example, 1A or 1) numerals.
- Moving along the column from top to bottom is said to be "viewing the group."
Find out why there are blank cells in the table. Elements are ordered not only according to their atomic number, but also according to groups (elements of one group have similar physical and chemical properties). This makes it easier to understand how a particular element behaves. However, with the growth of the atomic number, the elements that fall into the corresponding group are not always found, therefore, 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 57 through 102 are classified as rare earth elements, and are usually listed in a separate subgroup in the lower right corner of the table.
Each row in the table represents a period. All elements of the same period have the same number of atomic orbitals on which the electrons in the atoms are located. The number of orbitals corresponds to the number of the period. 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.
- Moving along the line from left to right is said to be "viewing a period."
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 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, which is the same in most languages. When doing experiments and working with chemical equations, symbols for the elements are commonly used, so it is helpful to remember them.
  - Typically, element symbols are an abbreviation of their Latin name, although for some, especially recently discovered elements, they are derived from a 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 shown in the table. This "name" of the element is used in normal text. For example, "helium" and "carbon" are the names of the elements. Usually, although not always, the full names of the elements are listed 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 the atom. All atoms of an element contain the same number of protons. Unlike electrons, the number of protons in an element's atoms remains constant. Otherwise, another chemical element would have turned out!
  - The atomic number of an element can also determine the number of electrons and neutrons in an atom.
5. Usually the number of electrons is equal to the number of protons. An exception is the case when the atom is ionized. Protons are positively charged and electrons are negatively charged. Since atoms are usually neutral, they contain the same number of electrons and protons. However, an atom can capture or lose electrons, in which case it ionizes.
  - Ions are electrically charged. If there are more protons in the ion, then it has a positive charge, and in this case a plus sign is placed after the element symbol. If the ion contains more electrons, it has a negative charge, which is indicated by a minus sign.
  - The plus and minus signs are not used if the atom is not an ion.

On March 1, 1869, Mendeleev completed his work "Experience of a system of elements based on their atomic weight and chemical similarity." This day is considered the day of the discovery of the periodic law of the elements of D.M. Mendeleev. "The discovery of DI Mendeleev refers to the fundamental laws of the universe, such as Newton's law of universal gravitation or Einstein's theory of relativity, and D.M. Mendeleev is on a par with the names of these great physicists." Academician A.I. Rusanov.
"The periodic table has been and remains the main guiding star in the most recent solutions to the problem of matter." Prof. A. N. Reformatsky.

"When you approach the assessment of personalities like D. I. Mendeleev, to the analysis of their scientific work, one involuntarily comes to the desire to find in this work the elements most marked by the stamp of genius. Of all the signs that distinguish genius and its manifestation, two seem to be the most revealing: firstly, the ability to cover and unite broad areas of knowledge and, secondly, the ability to abrupt leaps of thought, to unexpected convergence of facts and concepts that, for an ordinary mortal, seem to be far apart and unrelated, at least until the moment when such a connection is discovered and proven. " L. A. Chugaev, professor of chemistry.

And Mendeleev himself understood the enormous significance of the law he discovered for science. And believed in him further development... "Apparently, the future does not threaten the periodic law with destruction, but only promises superstructures and development." DI. Mendeleev.

The original view of the table, written by D.I. Mendeleev.
If all the scientific knowledge of the world were lost due to some kind of cataclysm, then for the revival of civilization one of the main laws would be the periodic law of D.I. Mendeleev. Advances in atomic physics, including nuclear power and fusion artificial elements, became possible only thanks to the Periodic Law. In turn, they expanded and deepened the essence of Mendeleev's law.

The periodic law played a huge role in the development of chemistry and other natural sciences. The mutual connection was discovered between all elements, their physical and chemical properties. This put before natural science a scientific and philosophical problem of great importance: this mutual connection must be explained.
The discovery of the periodic law was preceded by 15 years of hard work. By the time the periodic law was discovered, 63 chemical elements were known, there were about 50 different classifications. Most scientists compared only elements with similar properties to each other, so they could not discover the law. Mendeleev, on the other hand, compared everything, including dissimilar elements. Mendeleev wrote on cards all the known information about the chemical elements and their compounds discovered and studied at that time, arranged them in the order of increasing their relative atomic masses and comprehensively analyzed this entire set, trying to find certain patterns in it. As a result of intense creative work, he discovered in this chain segments in which the properties of chemical elements and the substances formed by them changed in a similar way - periodically - periods. With the development of the theory of the structure of the electron shell of atoms, it became clear why the properties of atoms show periodicity with increasing atomic mass. Atoms with the same outer sphere make up one group. Atoms with the same number of outer spheres are one row. Atoms with nuclei that have the same charges, but different masses, have the same chemical properties, but different atomic weights, and are isotopes of the same chemical element. Essentially, the properties of atoms reflect the properties of the outer electron shells, which are closely related to the laws of quantum physics.

The periodic table itself has been transformed many times, displaying different information about the properties of atoms. There are also curious tables.

The so-called short-period or short form of TM

Long-period or long form of TM

Extra long.

State flags indicating the country where the item was first discovered.

The names of elements that were canceled or turned out to be erroneous, such as the story of Didymus Di, turned out to be a mixture of two newly discovered elements, praseodymium and neodymium.

Here, in blue, the elements formed during Big bang, in blue - synthesized during primary nucleosynthesis, yellow and green colors denote elements synthesized, respectively, in the bowels of "small" and "large" stars. Pink - substances (nuclei) synthesized during supernova explosions. By the way, gold (Au) is still synthesized during collisions of neutron stars. Purple - artificially created in laboratories. But that's not the whole story ...

Here, different colors indicate organic, inorganic and irreplaceable elements necessary for building the bodies of living beings, including us.

Table-tower
Proposed in 2006 by Vitaly Zimmerman based on the ideas of Charles Janet. He studied the orbital filling of atoms - how the electrons are positioned relative to the nucleus. And on the basis of this, he divided all the elements into four groups, sorting them according to the configurations of the position of the electrons. The table is extremely simple and functional.

The table is a spiral.
In 1964, Theodore Benfey proposed to place hydrogen (H) in the center of the table, and place the other elements around it in a spiral that spins clockwise. Already at the second turn, the helix stretches into loops, which correspond to transition metals and lanthanides with actinides, and a place is provided for so far unknown superactinides. This gives the table the look of an extravagant design solution.

The table is a rainbow spiral.
Invented in 1975 by chemist James Hyde. He was fond of organosilicon compounds, so it was flint that got into the base of the table, since it has a large number of bonds with other elements. Various categories of elements are also grouped into sectors and marked with the desired color. The table is more beautiful than analogs, but because of the curved shape it is not easy to use it.

These tables show the sequence of filling the electronic casings. Some of them, anyway. All these tables look very exotic.
Isotope table. It displays the "lifetime" of various isotopes, their stability depending on the mass of the nucleus. However, this is no longer the periodic table, it is completely different ( nuclear physics) history...

He drew on the writings of Robert Boyle and Antoine Lavusier. The first scientist advocated the search for irreducible chemical elements. Boyle listed 15 of these as early as 1668.

Lavusier added another 13 to them, but a century later. The search dragged on because there was no coherent theory of the relationship between the elements. Finally, Dmitry Mendeleev entered the “game”. He decided that there is a connection between the atomic mass of substances and their place in the system.

This theory allowed the scientist to discover dozens of elements without discovering them in practice, but in nature. This was the responsibility of the descendants. But, now is not about them. Let's devote this article to the great Russian scientist and his table.

The history of the creation of the periodic table

Mendeleev table began with the book "Correlation of properties with the atomic weight of elements." Labor was released in the 1870s. At the same time, the Russian scientist spoke to the chemical society of the country and sent the first version of the table to colleagues from abroad.

Before Mendeleev, 63 elements were discovered by different scientists. Our compatriot began by comparing their properties. First of all, he worked with potassium and chlorine. Then he took up a group of alkaline metals.

The chemist got a special table and cards of elements to play them like solitaire, looking for the necessary matches and combinations. As a result, an insight came: - the properties of the components depend on the mass of their atoms. So, elements of the periodic table lined up in ranks.

The find of the maestro of chemistry was the decision to leave emptiness in these rows. The periodicity of the difference between atomic masses made the scientist assume that not all the elements are known to mankind yet. The weight gaps between some of the "neighbors" were too great.

That's why, periodic table has become like a chessboard, with an abundance of "white" cells. Time has shown that they really were waiting for their "guests". They are, for example, inert gases. Helium, neon, argon, krypton, radioactive and xenon were discovered only in the 30s of the 20th century.

Now about the myths. It is widely believed that chemical periodic table appeared to him in a dream. These are the intrigues of university teachers, more precisely, one of them - Alexander Inostrantsev. This is a Russian geologist who lectured at the Petersburg University of Mining.

Inostrantsev was familiar with Mendeleev, he was visiting him. Once, exhausted by the search, Dmitry fell asleep right in front of Alexander. He waited until the chemist woke up and saw Mendeleev grabbing a piece of paper and writing down the final version of the table.

In fact, the scientist simply did not have time to do this before Morpheus captured him. However, Inostrantsev wanted to amuse his students. Based on what he saw, the geologist came up with a bike that grateful listeners quickly spread to the masses.

Features of the periodic table

Since the first version of 1969 periodic table has been refined more than once. So, with the discovery in the 1930s of noble gases, it was possible to derive a new dependence of the elements - on their serial numbers, and not on the mass, as the author of the system stated.

The concept of "atomic weight" was replaced by "atomic number". Managed to study the number of protons in the nuclei of atoms. This number is the ordinal number of the element.

Scientists of the 20th century also studied the electronic structure of atoms. It also affects the periodicity of elements and is reflected in later editions. periodic tables. Photo the list demonstrates that the substances in it are arranged as the atomic weight increases.

They did not change the fundamental principle. The mass increases from left to right. At the same time, the table is not single, but divided into 7 periods. Hence the name of the list. The period is a horizontal row. Its beginning is typical metals, the end is elements with non-metallic properties. The decrease is gradual.

There are large and small periods. The first ones are at the beginning of the table, there are 3 of them. The list opens with a period of 2 elements. This is followed by two columns, each containing 8 items. The remaining 4 periods are large. The 6th is the longest, it has 32 elements. In the 4th and 5th there are 18 of them, and in the 7th - 24.

You can count how many elements are in the table Mendeleev. There are 112 items in total. Namely names. The cells are 118, and there are variations of the list with 126 fields. There are still empty cells for unopened, unnamed elements.

Not all periods fit on one line. Large periods consist of 2 rows. The amount of metals in them outweighs. Therefore, the bottom lines are completely devoted to them. A gradual decrease from metals to inert substances is observed in the upper rows.

Pictures of the periodic table divided and vertically. it groups in the periodic table, there are 8. Vertically arranged elements similar in chemical properties... They are divided into main and secondary subgroups. The latter begin only from the 4th period. The main subgroups also include elements of small periods.

The essence of the periodic table

Names of elements in the periodic table- these are 112 positions. The essence of their arrangement in a single list is the systematization of primary elements. They began to fight over this back in ancient times.

Aristotle was one of the first to understand what all things are made of. He took as a basis the properties of substances - cold and warm. Empidocles identified 4 fundamental principles according to the elements: water, earth, fire and air.

Metals in the periodic table, like other elements, are the very first principles, but from a modern point of view. The Russian chemist managed to discover most of the components of our world and to assume the existence of as yet unknown primary elements.

It turns out that pronunciation of the periodic table- sounding a certain model of our reality, decomposing it into its components. However, they are not easy to learn. Let's try to make things easier by describing a couple of effective methods.

How to learn the periodic table

Let's start with the modern method. A number of flash games have been developed by computer scientists to help memorize Mendeleev's list. Project participants are offered to find elements by different options, for example, name, atomic mass, letter designation.

The player has the right to choose the field of activity - only part of the table, or all of it. It is in our will, as well, to exclude the names of elements, other parameters. This makes it harder to find. For advanced, a timer is also provided, that is, training is conducted at speed.

Game conditions make learning numbers of elements in the Mendnleev table not boring, but entertaining. Excitement wakes up, and it becomes easier to organize knowledge in the head. Those who dislike computer flash projects suggest a more traditional way of memorizing the list.

It is divided into 8 groups, or 18 (in accordance with the 1989 edition). For ease of memorization, it is better to create several separate tables, rather than work on an integral version. Visual images, matched to each of the elements, also help. You should rely on your own associations.

So, iron in the brain can correlate, for example, with a nail, and mercury with a thermometer. Item name unfamiliar? We use the method of suggestive associations. , for example, let's compose the words "toffee" and "speaker" from the beginnings.

Characteristics of the periodic table do not study in one sitting. Classes are recommended for 10-20 minutes a day. It is recommended to start by memorizing only the main characteristics: the name of the element, its designation, atomic mass and serial number.

Schoolchildren prefer to hang the periodic table above their desk, or on a wall that they often look at. The method is good for people with a predominance of visual memory. Data from the list is involuntarily remembered even without cramming.

Teachers also take this into account. As a rule, they do not force the list to be memorized, they are allowed to look at it even at the control ones. Constantly glancing at a spreadsheet is tantamount to the effect of printing on the wall, or writing cheat sheets before exams.

Coming to the study, remember that Mendeleev did not immediately remember his list. Once, when the scientist was asked how he opened the table, the answer followed: “I’ve been thinking about it for 20 years, but you think: I was sitting and, suddenly, it’s ready.” The periodic system is painstaking work that cannot be mastered in a short time.

Science does not tolerate haste, because it leads to delusions and annoying mistakes. So, simultaneously with Mendeleev, Lothar Meyer compiled the table. However, the German did not complete the list a little and was not convincing in proving his point of view. Therefore, the public recognized the work of the Russian scientist, and not his fellow chemist from Germany.

Four ways to attach nucleons
The mechanisms of nucleon attachment can be divided into four types, S, P, D, and F. These types of attachment are reflected by the color background in the presented version of the table by D.I. Mendeleev.
The first type of attachment is the S scheme, when nucleons attach to the nucleus along the vertical axis. The mapping of attached nucleons of this type in the internuclear space is now identified as S electrons, although there are no S electrons in this zone, but there are only spherical regions of space space charge that provide molecular interaction.
The second type of attachment is the P scheme, when nucleons attach to the nucleus in the horizontal plane. The mapping of these nucleons in the internuclear space is identified as P electrons, although this, too, is just a region of space charge generated by the nucleus in the internuclear space.
The third type of attachment is the D scheme, when nucleons are attached to neutrons in the horizontal plane, and finally, the fourth type of attachment is the F scheme, when nucleons are attached to neutrons along the vertical axis. Each type of attachment gives the atom the properties characteristic of this type of connection, therefore, in the composition of the periods of the table D.I. Mendeleev, subgroups have long been identified, according to the type of S, P, D and F bonds.
Since with the addition of each subsequent nucleon, an isotope of either the preceding or subsequent element is formed, the exact arrangement of nucleons by the type of S, P, D and F bonds can be shown only using the Table of Known Isotopes (Nuclides), a version of which (from Wikipedia) we used.
We divided this table into periods (see the Period filling tables), and in each period we indicated the scheme according to which each nucleon joins. Since, in accordance with the microquantum theory, each nucleon can join the nucleus only in a strictly defined place, the number and schemes of nucleon attachment in each period are different, but in all periods of the D.I. Mendeleev's laws of nucleon attachment are fulfilled UNIFORMALLY for all nucleons without exception.
As you can see, in the II and III periods, the addition of nucleons proceeds only according to the S and P schemes, in the IV and V periods - according to the S, P and D schemes, and in the VI and VII periods - according to the S, P, D and F schemes. At the same time, it turned out that the laws of addition of nucleons are fulfilled so precisely that it was not difficult for us to calculate the composition of the nucleus of the final elements of the VII period, which are in the table of D.I. Mendeleev are numbered 113, 114, 115, 116 and 118.
According to our calculations, the last element of the VII period, which we called Rs (“Russia” from “Russia”), consists of 314 nucleons and has isotopes 314, 315, 316, 317 and 318. The preceding element Nr (“Novorossiy” from “ Novorossiya ") consists of 313 nucleons. We will be very grateful to everyone who can confirm or deny our calculations.
To be honest, we ourselves are amazed at how accurately the Universal Constructor works, which ensures that each subsequent nucleon is attached only to its own, only correct place, and if the nucleon does not stand up correctly, then the Constructor ensures the decay of the atom, and assembles a new atom from its spare parts. In our films, we showed only the main laws of the work of the Universal Designer, but there are so many nuances in its work that it will take the efforts of many generations of scientists to understand them.
But mankind needs to understand the laws of the work of the Universal Designer if it is interested in technological progress, since knowledge of the principles of the Universal Designer opens up completely new perspectives in all areas of human activity - from the creation of unique structural materials to the assembly of living organisms.