Signs of chemical elements. Periodic table of chemical elements by D.I. Mendeleev

The brilliant Russian chemist D.I. Mendeleev was distinguished throughout his life by the desire to understand the unknown. This desire, as well as the deepest and most extensive knowledge, combined with unmistakable scientific intuition, allowed Dmitry Ivanovich to develop a scientific classification of chemical elements - the Periodic System in the form of his famous table.

D.I. Mendeleev’s periodic system of chemical elements can be imagined as a large house in which absolutely all the chemical elements known to man “live together.” To be able to use the Periodic Table, you need to study the chemical alphabet, i.e., the signs of chemical elements.

With their help, you will learn to write words - chemical formulas, and on their basis you will be able to write sentences - equations of chemical reactions. Each chemical element is designated by its own chemical sign, or symbol, which, along with the name of the chemical element, is written in D.I. Mendeleev’s table. At the suggestion of the Swedish chemist J. Berzelius, the initial letters of the Latin names of chemical elements were adopted in most cases as symbols. Thus, hydrogen (Latin name Hydrogenium - hydrogenium) is denoted by the letter H (read "ash"), oxygen (Latin name Oxygenium - oxygenium) - by the letter O (read "o"), carbon (Latin name Сarboneum - carboneum) - by the letter C ( read "tse").

The Latin names of several more chemical elements begin with the letter C: calcium (

Calcium), copper (Cuprum), cobalt (Cobaltum), etc. To distinguish them, I. Berzelius proposed adding one of the subsequent letters of the name to the initial letter of the Latin name. Thus, the chemical sign for calcium is written with the symbol Ca (read “calcium”), copper - Cu (read “cuprum”), cobalt - Co (read “cobalt”).

The names of some chemical elements reflect the most important properties of the elements, for example, hydrogen - which produces water, oxygen - which produces acids, phosphorus - which carries light (Fig. 20), etc.

Rice. 20.
Etymology of the name of element No. 15 of the Periodic Table of D. I. Mendeleev

Other elements are named after celestial bodies or planets of the solar system - selenium and tellurium (Fig. 21) (from the Greek Selene - Moon and Telluris - Earth), uranium, neptunium, plutonium.

Rice. 21.
Etymology of the name of element No. 52 of the Periodic Table of D. I. Mendeleev

Some names are borrowed from mythology (Fig. 22). For example, tantalum. This was the name of the beloved son of Zeus. For crimes against the gods, Tantalus was severely punished. He stood up to his neck in water, and branches with juicy, fragrant fruits hung over him. However, as soon as he wanted to drink, the water flowed away from him; as soon as he wanted to satisfy his hunger, he stretched out his hand to the fruits - the branches deviated to the side. Trying to isolate tantalum from ores, chemists experienced no less torment.

Rice. 22.
Etymology of the name of element No. 61 of the Periodic Table of D. I. Mendeleev

Some elements were named after different states or parts of the world. For example, germanium, gallium (Gaul is the ancient name for France), polonium (in honor of Poland), scandium (in honor of Scandinavia), francium, ruthenium (Ruthenium is the Latin name for Russia), europium and americium. Here are the elements named after cities: hafnium (in honor of Copenhagen), lutetium (in the old days Paris was called Lutetium), berkelium (in honor of the city of Berkeley in the USA), yttrium, terbium, erbium, ytterbium (the names of these elements come from Ytterby - small city ​​in Sweden where the mineral containing these elements was first discovered), dubnium (Fig. 23).

Rice. 23.
Etymology of the name of element No. 105 of the Periodic Table of D. I. Mendeleev

Finally, the names of the elements immortalize the names of great scientists: curium, fermium, einsteinium, mendelevium (Fig. 24), lawrencium.

Rice. 24.
Etymology of the name of element No. 101 of the Periodic Table of D. I. Mendeleev

Each chemical element is assigned in the periodic table, in the common “house” of all elements, its own “apartment” - a cell with a strictly defined number. The deeper meaning of this number will be revealed to you as you further study chemistry. The number of floors of these “apartments” is also strictly distributed - the periods in which the elements “live”. Like the serial number of an element (the “apartment” number), the period (“floor”) number contains the most important information about the structure of the atoms of chemical elements. Horizontally - “storeys” - the Periodic Table is divided into seven periods:

• The 1st period includes two elements: hydrogen H and helium He;
• The 2nd period begins with lithium Li and ends with neon Ne (8 elements);
• The 3rd period begins with sodium Na and ends with argon Ar (8 elements).

The first three periods, each consisting of one row, are called small periods.

Periods 4, 5 and 6 each include two rows of elements; they are called large periods; The 4th and 5th periods contain 18 elements each, the 6th - 32 elements.

The 7th period is unfinished, so far it consists of only one row.

Pay attention to the “basement floors” of the Periodic Table - 14 twin elements “live” there, some similar in their properties to lanthanum La, others to actinium Ac, which represent them on the upper “floors” of the table: in the 6th and 7th -th periods.

Vertically, chemical elements “living” in “apartments” with similar properties are located below each other in vertical columns - groups, of which there are eight in D.I. Mendeleev’s table.

Each group consists of two subgroups - main and secondary. The subgroup, which includes elements of both short and long periods, is called the main subgroup or group A. The subgroup, which includes elements of only long periods, is called the secondary subgroup or group B. Thus, the main subgroup of group I (group IA) includes lithium , sodium, potassium, rubidium and francium are a subgroup of lithium Li; a side subgroup of this group (IB group) is formed by copper, silver and gold - this is a subgroup of Cu copper.

In addition to the form of D.I. Mendeleev’s table, which is called short-period (it is shown on the flyleaf of the textbook), there are many other forms, for example, the long-period version.

Just as a child can construct a huge number of different objects from the elements of the Lego game (see Fig. 10), so from chemical elements nature and man have created the variety of substances that surround us. Another model is even more clear: just as 33 letters of the Russian alphabet form various combinations, tens of thousands of words, so 114 chemical elements in various combinations create more than 20 million different substances.

Try to learn the laws of the formation of words - chemical formulas, and then the world of substances will open before you in all its colorful diversity.

But to do this, first learn the letters - symbols of chemical elements (Table 1).

Table 1
Names of some chemical elements

Key words and phrases

1. Periodic table of chemical elements (table) by D. I. Mendeleev.
2. Periods large and small.
3. Groups and subgroups - main (A group) and secondary (B group).
4. Symbols of chemical elements.

Work with computer

1. Refer to the electronic application. Study the lesson material and complete the assigned tasks.
2. Find email addresses on the Internet that can serve as additional sources that reveal the content of keywords and phrases in the paragraph. Offer your help to the teacher in preparing a new lesson - make a report on the key words and phrases of the next paragraph.

Questions and tasks

1. Using dictionaries (etymological, encyclopedic and chemical terms), name the most important properties that are reflected in the names of chemical elements: bromine Br, nitrogen N, fluorine F.
2. Explain how the names of the chemical elements titanium and vanadium reflect the influence of ancient Greek myths.
3. Why is the Latin name for gold Aurum (aurum) and silver - Argentum (argentum)?
4. Tell the story of the discovery of a chemical element of your choice and explain the etymology of its name.
5. Write down the “coordinates”, i.e. the position in the Periodic Table of D.I. Mendeleev (element number, period number and its type - large or small, group number and subgroup - main or minor), for the following chemical elements: calcium, zinc , antimony, tantalum, europium.
6. Distribute the chemical elements listed in Table 1 into three groups based on the “pronunciation of the chemical symbol.” Could doing this activity help you remember chemical symbols and pronounce element symbols?

Bess Ruff is a graduate student at Florida State University working on a PhD in geography. She received her Master's degree in Environmental Science and Management from the University of California, Santa Barbara in 2016. She has conducted research for marine spatial planning projects in the Caribbean and provided scientific support as a chartered member of the Sustainable Fisheries Group.

Number of sources used in this article: . You will find a list of them at the bottom of the page.

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

Steps

Part 1

Table structure

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

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

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

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

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

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

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

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

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

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

   Part 2

   Element designations

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

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

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

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

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

      • The atomic number is always an integer.

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

      • 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. The exception is the case when the atom is ionized. Protons have a positive charge and electrons have a negative charge. Because atoms are usually neutral, they contain the same number of electrons and protons. However, an atom can gain or lose electrons, in which case it becomes ionized.

      • Ions have an electrical charge. If an ion has more protons, it has a positive charge, in which case a plus sign is placed after the element symbol. If an ion contains more electrons, it has a negative charge, indicated by a minus sign.
      • The plus and minus signs are not used if the atom is not an ion.

Chemical reactions involve the transformation of one substance into another. To understand how this happens, you need to remember from the course of natural history and physics that substances consist of atoms. There are a limited number of types of atoms. Atoms can connect to each other in different ways. Just as hundreds of thousands of different words are formed when adding the letters of the alphabet, molecules or crystals of different substances are formed from the same atoms.

Atoms can form molecules- the smallest particles of a substance that retain its properties. For example, several substances are known that are formed from only two types of atoms - oxygen atoms and hydrogen atoms, but from different types of molecules. These substances include water, hydrogen and oxygen. A water molecule consists of three particles bound to each other. These are atoms.

An oxygen atom (oxygen atoms are designated in chemistry by the letter O) is attached to two hydrogen atoms (they are designated by the letter H).

The oxygen molecule consists of two oxygen atoms; A hydrogen molecule is made up of two hydrogen atoms. Molecules can be formed during chemical transformations, or they can disintegrate. Thus, each water molecule breaks down into two hydrogen atoms and one oxygen atom. Two water molecules form twice as many hydrogen and oxygen atoms.

Identical atoms bond in pairs to form molecules of new substances– hydrogen and oxygen. The molecules are thus destroyed, but the atoms are preserved. This is where the word “atom” comes from, which means in translation from ancient Greek "indivisible".

Atoms are the smallest chemically indivisible particles of matter

In chemical transformations, other substances are formed from the same atoms that made up the original substances. Just as microbes became accessible to observation with the invention of the microscope, so atoms and molecules became accessible to observation with the invention of instruments that provided even greater magnification and even made it possible to photograph atoms and molecules. In such photographs, atoms appear as blurry spots, and molecules appear as a combination of such spots. However, there are also phenomena in which atoms divide, atoms of one type turn into atoms of other types. At the same time, atoms that are not found in nature are also obtained artificially. But these phenomena are studied not by chemistry, but by another science - nuclear physics. As already mentioned, there are other substances that contain hydrogen and oxygen atoms. But, regardless of whether these atoms are part of water molecules or part of other substances, these are atoms of the same chemical element.

A chemical element is a specific type of atom How many types of atoms are there? Today, people reliably know about the existence of 118 types of atoms, that is, 118 chemical elements. Of these, 90 types of atoms are found in nature, the rest are obtained artificially in laboratories.

Chemical element symbols

In chemistry, chemical symbols are used to designate chemical elements. This is the language of chemistry. To understand speech in any language, you need to know the letters, and it’s the same in chemistry. To understand and describe the properties of substances and the changes that occur with them, first of all, you need to know the symbols of chemical elements. In the era of alchemy, much less chemical elements were known than now. Alchemists identified them with planets, various animals, and ancient deities. Currently, the notation system introduced by the Swedish chemist Jöns Jakob Berzelius is used all over the world. In his system, chemical elements are designated by the initial or one of the subsequent letters of the Latin name of a given element. For example, the element silver is represented by the symbol – Ag (lat. Argentum). Below are the symbols, symbol pronunciations, and names of the most common chemical elements. They need to be memorized!

The Russian chemist Dmitry Ivanovich Mendeleev was the first to organize the diversity of chemical elements, and based on the Periodic Law he discovered, he compiled the Periodic System of chemical elements. How is the Periodic Table of chemical elements organized? Figure 58 shows a short-period version of the Periodic Table. The Periodic Table consists of vertical columns and horizontal rows. Horizontal lines are called periods. To date, all known elements are placed in seven periods.

The periods are designated by Arabic numerals from 1 to 7. Periods 1–3 consist of one row of elements - they are called small.

Periods 4–7 consist of two rows of elements; they are called major. The vertical columns of the Periodic Table are called groups of elements.

There are eight groups in total, and Roman numerals from I to VIII are used to designate them.

There are main and secondary subgroups. Periodic Table– a universal reference book for a chemist, with its help you can get information about chemical elements. There is another type of Periodic System - long-period. In the long-period form of the Periodic Table, the elements are grouped differently, and are divided into 18 groups.

PeriodicSystems elements are grouped into “families”, that is, within each group of elements there are elements with similar, similar properties. In this version Periodic System, group numbers, as well as periods, are indicated in Arabic numerals. Periodic System of Chemical Elements D.I. Mendeleev

Prevalence of chemical elements in nature

The atoms of elements found in nature are distributed very unevenly. In space, the most common element is hydrogen - the first element of the Periodic Table. It accounts for about 93% of all atoms in the Universe. About 6.9% are helium atoms, the second element of the Periodic Table.

The remaining 0.1% comes from all other elements.

The abundance of chemical elements in the earth's crust differs significantly from their abundance in the Universe. The earth's crust contains the most atoms of oxygen and silicon. Together with aluminum and iron, they form the main compounds of the earth's crust. And iron and nickel- the main elements that make up the core of our planet.

Living organisms are also composed of atoms of various chemical elements. The human body contains the most atoms of carbon, hydrogen, oxygen and nitrogen.

Summary of the article about Chemical elements.

• Chemical element– a certain type of atom
• Today, people reliably know about the existence of 118 types of atoms, that is, 118 chemical elements. Of these, 90 types of atoms are found in nature, the rest are obtained artificially in laboratories
• There are two versions of the Periodic Table of Chemical Elements D.I. Mendeleev - short period and long period
• Modern chemical symbols are derived from the Latin names of chemical elements
• Periods– horizontal lines of the Periodic Table. Periods are divided into small and large
• Groups– vertical rows of the periodic table. Groups are divided into main and secondary

The periodic table of elements was the first natural classification of chemical elements, showing that they are interrelated with each other, and also served as a basis for further research.

When Mendeleev compiled his table based on the periodic law he discovered, many elements were still unknown. Like, for example, the three elements of the 4th period. Presumably the elements were called ekaboron (its properties should resemble boron), ekaaluminum, ecasilicium. Within 15 years, Mendeleev's predictions were confirmed. French chemist Lecoq de Boisbaudran discovered gallium, which has all the properties of eka-aluminium, L.F. Nilson discovered scandium, and K.A. Winkler discovered the element germanium, which has the properties of eca-silicon.

The discovery of Ga, Sc, Ge is proof of the existence of the periodic law. The periodic system was also of great importance in establishing the valency and atomic masses of some elements, correcting some of them. Transuranium elements have now been created based on the periodic law.

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Aluminum is located in the 3rd group of the main subgroup, in the 3rd period. Serial number 13. Atomic mass ~27. P-element. Electronic configuration: 1s22s22p63s23p1.On out

Aluminum oxide and hydroxide
Aluminum oxide – Al2O3. Physical properties: aluminum oxide is a white amorphous powder or very hard white crystals. Molecular weight = 101.96, density – 3.97

General characteristics of the chromium subgroup
The elements of the chromium subgroup occupy an intermediate position in the series of transition metals. They have high melting and boiling points, free spaces on electronic

Chromium oxides and hydroxides
Chromium forms three oxides: CrO, Cr2O3 and CrO3. Chromium II oxide (CrO) – basic oxide – black powder. Strong reducing agent. CrO dissolves in dilute hydrochloric acid

Chromates and dichromates
Chromates are salts of chromic acid H2Cr04, which exists only in aqueous solutions with a concentration of no more than 75%. The valence of chromium in chromates is 6. Chromates are

General characteristics of the iron family
The iron family is part of a secondary subgroup of the eighth group and is the first triad in it, including iron, cobalt, nickel

Iron compounds
Iron (II) oxide FeO is a black crystalline substance, insoluble in water and alkalis. FeO corresponds to the base Fe(OH)2.

Domain process
The blast furnace process is the smelting of pig iron in a blast furnace. The blast furnace is lined with refractory bricks with a height of 30 m and an internal diameter of 12 m. The upper half is w

Cast iron and steel
Iron alloys are metal systems whose main component is iron. Classification of iron alloys: 1) alloys of iron with carbon (n

Heavy water
Heavy water is deuterium oxide D2O with oxygen of natural isotopic composition, a colorless, odorless and tasteless liquid. Heavy water was open

Chemical and physical properties
Heavy water has a boiling point of 101.44 °C and a melting point of 3.823 °C. D2O crystals have the same structure as regular ice crystals, the difference is in size

Salts of hydrochloric acid
Salts of hydrochloric acid or chlorides are chlorine compounds with all elements having a lower electronegativity value. Metal chlorides

Learning new material .

Dmitri Ivanovich Mendeleev- a brilliant Russian scientist who managed to create a strictly scientific classification of chemicals. elements, which is the Periodic Table. It contains all the chemical elements known to science, the entire diversity of the surrounding world is built from elements, the elements in this table are usually designated by chemical signs or symbols. In order to use the table, you need to know the “chemical language” or “chemical alphabet”. There are 33 letters in the Russian alphabet, and 109 in the chemical alphabet.

In this message you will learn how to correctly designate chemical elements.

Signs of chemical elements.

So, in your opinion, it is easiest to write a chemical phenomenon with signs, but what kind?

The same problem faced the chemists of the Middle Ages.

At that time, scientists, they were called, as you remember, alchemists, knew 10 chemical elements - seven metals (gold, silver, copper, iron, tin, lead and mercury) and three non-metals (sulfur, carbon and antimony).

Alchemists believed that chemical elements were associated with the stars and planets, and assigned astrological symbols to them.

Gold was called the Sun, and was designated by a circle with a dot.Copper is Venus; the symbol of this metal was the “Venus mirror”. Alchemists did without chemical formulas for a very long time. Strange symbols were in use, with almost every chemist using his own system of notation for substances. It was very inconvenient. There was real confusion: the same chemical reactions were written with different signs. It was necessary to introduce a unified notation system.

In the 18th century, a system of designating elements (of which there were already three dozen known at that time) took root in the form of geometric shapes - circles, semicircles, triangles, squares.

The symbols for chemical elements currently used were introduced by the Swedish chemist Jens Jakob Berzelius.

Each element has its own symbol, understandable to scientists from any country. The first, uppercase, letter of a symbol is always the first letter of the full Latin name of the element. If the names of several elements begin with such a letter, then another letter is added to the first one.

For example: Oxygen – Oxуgenium – O

Carbon – Сarboneum – C

Calcium – Сalcium – Ca

The characters are pronounced according to the letter of the Latin alphabet.

For example: oxygen – O – “o”

nitrogen – N – “en”

Others are read in Russian.

For example: calcium – Ca – “calcium”

Sodium – Na – “sodium”

You don't need to memorize all the elements. But for our further work, a number of elements need to be learned.

All of them are written down in the textbook on page 35. All elements can be divided into metals and non-metals.

Etymology of the names of chemical elements:

Let's consider the etymology of the names of chemical elements, i.e. origin of their names.

The name reflects the most important property of a simple substance formed by this element: hydrogen – “giving birth to water”, phosphorus – “carrying light”

Myths of the ancient Greeks: promethium - prometheus, tantalum - tantalum

• geographical names

Geographical names: states – gallium, germanium, polonium, ruthenium; cities - lutetium (Paris), hafnium (Copenhagen).

• astronomical names

Astronomy: selenium - moon, tellurium - earth, uranium, neptunium

• names of scientists

Names of great scientists: fermium, curium, einsteinium, mendelevium

Structure of the Periodic Table of Chemical Elements by D.I. Mendeleev

Now we will look at perhaps the most important document, a “tip” for any chemist. Open the flyleaf of your textbook, and also use the tables that are on your desks. In front of you is the table “Periodic Table of Dmitry Ivanovich Mendeleev.” As you can see, they are slightly different, but not significantly. The periodic table is the Big House of Chemical Elements, which was built in 1869 by D.I. Mendeleev.

GROUPS, each of which consists of a main (elements on the left) and a secondary (elements on the right) subgroup. Each element has its own separate “apartment” with a serial number.

Some "entrances" are groups , have common names reflecting their general properties: alkali metals, halogens, noble or inert gases .

In addition, separately below, in the “basement,” there are lanthanides and actinides, which are very similar to lanthanum, and others to actinium.

The table also reflects the element’s belonging to a specific group: metal, non-metal or transition element.