How to read lithium in the periodic table. Designation, pronunciation, names and symbols of chemical elements. What have we learned

Classification inorganic substances and their nomenclature are based on the simplest and most constant characteristic over time - chemical composition , which shows the atoms of the elements that form a given substance, in their numerical ratio. If a substance is made up of atoms of one chemical element, i.e. is a form of existence of this element in a free form, then it is called a simple substance; if the substance is made up of atoms of two or more elements, then it is called complex substance. All simple substances (except monatomic) and all complex substances are called chemical compounds , since in them the atoms of one or different elements are interconnected by chemical bonds.

The nomenclature of inorganic substances consists of formulas and names. Chemical formula - depiction of the composition of a substance using symbols chemical elements, numerical indices and some other signs. chemical name - a representation of the composition of a substance using a word or group of words. The construction of chemical formulas and names is determined by the system nomenclature rules.

Symbols and names of chemical elements are given in the Periodic system of elements of D.I. Mendeleev. Elements are conditionally divided into metals and nonmetals . Non-metals include all elements of the VIIIA group (noble gases) and VIIA group (halogens), elements of the VIA group (except polonium), elements nitrogen, phosphorus, arsenic (VA group); carbon, silicon (IVA-group); boron (IIIA-group), as well as hydrogen. The remaining elements are classified as metals.

When compiling the names of substances, Russian names of elements are usually used, for example, dioxygen, xenon difluoride, potassium selenate. By tradition, for some elements, the roots of their Latin names are introduced into derivative terms:

For example: carbonate, manganate, oxide, sulfide, silicate.

Titles simple substances consist of one word - the name of a chemical element with a numerical prefix, for example:

The following numerical prefixes:

An indefinite number is indicated by a numerical prefix n- poly.

For some simple substances also use special names such as O 3 - ozone, P 4 - white phosphorus.

Chemical formulas complex substances are made up of the designation electropositive(conditional and real cations) and electronegative(conditional and real anions) components, for example, CuSO 4 (here Cu 2+ is a real cation, SO 4 2 is a real anion) and PCl 3 (here P + III is a conditional cation, Cl -I is a conditional anion).

Titles complex substances make up the chemical formulas from right to left. They consist of two words - the names of the electronegative components (in the nominative case) and the electropositive components (in genitive case), for example:

CuSO 4 - copper(II) sulfate
PCl 3 - phosphorus trichloride
LaCl 3 - lanthanum(III) chloride
CO - carbon monoxide

The number of electropositive and electronegative components in the names is indicated by the numerical prefixes given above (universal method), or by the oxidation states (if they can be determined by the formula) using Roman numerals in parentheses (the plus sign is omitted). In some cases, the ion charge is given (for complex cations and anions), using Arabic numerals with the corresponding sign.

The following special names are used for common multielement cations and anions:

H 2 F + - fluoronium	C 2 2 - - acetylenide
H 3 O + - oxonium	CN - - cyanide
H 3 S + - sulfonium	CNO - - fulminate
NH 4 + - ammonium	HF 2 - - hydrodifluoride
N 2 H 5 + - hydrazinium (1+)	HO 2 - - hydroperoxide
N 2 H 6 + - hydrazinium (2+)	HS - - hydrosulfide
NH 3 OH + - hydroxylaminium	N 3 - - azide
NO + - nitrosyl	NCS - - thiocyanate
NO 2 + - nitroyl	O 2 2 - - peroxide
O 2 + - dioxygenyl	O 2 - - superoxide
PH 4 + - phosphonium	O 3 - - ozonide
VO 2 + - vanadyl	OCN - - cyanate
UO 2 + - uranyl	OH - - hydroxide

For a small number of well-known substances also use special titles:

1. Acid and basic hydroxides. salt

Hydroxides - a type of complex substances, which include atoms of a certain element E (except for fluorine and oxygen) and the hydroxo group OH; general formula of hydroxides E (OH) n, where n= 1÷6. Hydroxide form E(OH) n called ortho-form; at n> 2 hydroxide can also be found in meta-form, including, in addition to E atoms and OH groups, oxygen atoms O, for example, E (OH) 3 and EO (OH), E (OH) 4 and E (OH) 6 and EO 2 (OH) 2.

Hydroxides are divided into two chemically opposite groups: acidic and basic hydroxides.

Acid hydroxides contain hydrogen atoms, which can be replaced by metal atoms, subject to the rule of stoichiometric valence. Most acid hydroxides are found in meta-form, and hydrogen atoms in the formulas of acid hydroxides are put in the first place, for example, H 2 SO 4, HNO 3 and H 2 CO 3, and not SO 2 (OH) 2, NO 2 (OH) and CO (OH) 2. The general formula of acid hydroxides is H X EO at, where the electronegative component EO y x - called an acid residue. If not all hydrogen atoms are replaced by a metal, then they remain in the composition of the acid residue.

The names of common acid hydroxides consist of two words: their own name with the ending "aya" and the group word "acid". We give formulas and own names common acid hydroxides and their acid residues (dash means that the hydroxide is not known in free form or in acidic aqueous solution):

acid hydroxide	acid residue
HAsO 2 - metaarsenic	AsO 2 - - metaarsenite
H 3 AsO 3 - orthoarsenic	AsO 3 3 - - orthoarsenite
H 3 AsO 4 - arsenic	AsO 4 3 - - arsenate
	B 4 O 7 2 - - tetraborate
	ВiО 3 - - bismuthate
HBrO - bromine	BrO - - hypobromite
HBrO 3 - bromine	BrO 3 - - bromate
H 2 CO 3 - coal	CO 3 2 - - carbonate
HClO - hypochlorous	ClO- - hypochlorite
HClO 2 - chloride	ClO 2 - - chlorite
HClO 3 - chlorine	ClO 3 - - chlorate
HClO 4 - chlorine	ClO 4 - - perchlorate
H 2 CrO 4 - chrome	CrO 4 2 - - chromate
	НCrO 4 - - hydrochromate
H 2 Cr 2 O 7 - dichromic	Cr 2 O 7 2 - - dichromate
	FeO 4 2 - - ferrate
HIO 3 - iodine	IO3- - iodate
HIO 4 - metaiodine	IO 4 - - metaperiodate
H 5 IO 6 - orthoiodic	IO 6 5 - - orthoperiodate
HMnO 4 - manganese	MnO4- - permanganate
	MnO 4 2 - - manganate
	MoO 4 2 - - molybdate
HNO 2 - nitrogenous	NO 2 - - nitrite
HNO 3 - nitrogen	NO 3 - - nitrate
HPO 3 - metaphosphoric	PO 3 - - metaphosphate
H 3 PO 4 - orthophosphoric	PO 4 3 - - orthophosphate
	HPO 4 2 - - hydrogen orthophosphate
	H 2 PO 4 - - dihydrootophosphate
H 4 P 2 O 7 - diphosphoric	P 2 O 7 4 - - diphosphate
	ReO 4 - - perrhenate
	SO 3 2 - - sulfite
	HSO 3 - - hydrosulfite
H 2 SO 4 - sulfuric	SO 4 2 - - sulfate
	HSO 4 - - hydrosulphate
H 2 S 2 O 7 - dispersed	S 2 O 7 2 - - disulfate
H 2 S 2 O 6 (O 2) - peroxodisulfur	S 2 O 6 (O 2) 2 - - peroxodisulfate
H 2 SO 3 S - thiosulfuric	SO 3 S 2 - - thiosulfate
H 2 SeO 3 - selenium	SeO 3 2 - - selenite
H 2 SeO 4 - selenium	SeO 4 2 - - selenate
H 2 SiO 3 - metasilicon	SiO 3 2 - - metasilicate
H 4 SiO 4 - orthosilicon	SiO 4 4 - - orthosilicate
H 2 TeO 3 - telluric	TeO 3 2 - - tellurite
H 2 TeO 4 - metatellurium	TeO 4 2 - - metatellurate
H 6 TeO 6 - orthotelluric	TeO 6 6 - - orthotellurate
	VO3- - metavanadate
	VO 4 3 - - orthovanadate
	WO 4 3 - - tungstate

Less common acid hydroxides are named according to the nomenclature rules for complex compounds, for example:

The names of acid residues are used in the construction of the names of salts.

Basic hydroxides contain hydroxide ions, which can be replaced by acidic residues, subject to the rule of stoichiometric valency. All basic hydroxides are found in ortho-form; their general formula is M(OH) n, where n= 1.2 (rarely 3.4) and M n+ - metal cation. Examples of formulas and names of basic hydroxides:

The most important chemical property of basic and acid hydroxides is their interaction with each other with the formation of salts ( salt formation reaction), for example:

Ca (OH) 2 + H 2 SO 4 \u003d CaSO 4 + 2H 2 O

Ca (OH) 2 + 2H 2 SO 4 \u003d Ca (HSO 4) 2 + 2H 2 O

2Ca(OH) 2 + H 2 SO 4 = Ca 2 SO 4 (OH) 2 + 2H 2 O

Salts - a type of complex substances, which include cations M n+ and acid residues*.

Salts with the general formula M X(EO at)n called average salts, and salts with unsubstituted hydrogen atoms - sour salts. Sometimes salts also contain hydroxide and/or oxide ions; such salts are called main salts. Here are examples and names of salts:

	calcium orthophosphate
	Calcium dihydroorthophosphate
	Calcium hydrogen phosphate
	Copper(II) carbonate
Cu 2 CO 3 (OH) 2	Dicopper dihydroxide carbonate
	Lanthanum(III) nitrate
	Titanium oxide dinitrate

Acid and basic salts can be converted to medium salts by reaction with the corresponding basic and acidic hydroxide, for example:

Ca (HSO 4) 2 + Ca (OH) \u003d CaSO 4 + 2H 2 O

Ca 2 SO 4 (OH) 2 + H 2 SO 4 \u003d Ca 2 SO 4 + 2H 2 O

There are also salts containing two different cations: they are often called double salts, for example:

2. Acid and basic oxides

Oxides E X O at- products of complete dehydration of hydroxides:

Acid hydroxides (H 2 SO 4, H 2 CO 3) meet acidic oxides(SO 3, CO 2), and basic hydroxides (NaOH, Ca (OH) 2) - mainoxides(Na 2 O, CaO), and the oxidation state of the element E does not change when moving from hydroxide to oxide. An example of formulas and names of oxides:

Acid and basic oxides retain the salt-forming properties of the corresponding hydroxides when interacting with hydroxides of opposite properties or with each other:

N 2 O 5 + 2NaOH \u003d 2NaNO 3 + H 2 O

3CaO + 2H 3 PO 4 = Ca 3 (PO 4) 2 + 3H 2 O

La 2 O 3 + 3SO 3 \u003d La 2 (SO 4) 3

3. Amphoteric oxides and hydroxides

Amphoteric hydroxides and oxides - a chemical property consisting in the formation of two rows of salts by them, for example, for hydroxide and aluminum oxide:

(a) 2Al(OH) 3 + 3SO 3 = Al 2 (SO 4) 3 + 3H 2 O

Al 2 O 3 + 3H 2 SO 4 \u003d Al 2 (SO 4) 3 + 3H 2 O

(b) 2Al(OH) 3 + Na 2 O = 2NaAlO 2 + 3H 2 O

Al 2 O 3 + 2NaOH \u003d 2NaAlO 2 + H 2 O

Thus, hydroxide and aluminum oxide in reactions (a) exhibit the properties major hydroxides and oxides, i.e. react with acid hydroxides and oxide, forming the corresponding salt - aluminum sulfate Al 2 (SO 4) 3, while in reactions (b) they also exhibit properties acidic hydroxides and oxides, i.e. react with basic hydroxide and oxide, forming a salt - sodium dioxoaluminate (III) NaAlO 2 . In the first case, the aluminum element exhibits the property of a metal and is part of the electropositive component (Al 3+), in the second - the property of a non-metal and is part of the electronegative component of the salt formula (AlO 2 -).

If these reactions proceed in an aqueous solution, then the composition of the resulting salts changes, but the presence of aluminum in the cation and anion remains:

2Al(OH) 3 + 3H 2 SO 4 = 2 (SO 4) 3

Al(OH) 3 + NaOH = Na

Here square brackets denote complex ions 3+ - hexaaquaaluminum(III) cation, - - tetrahydroxoaluminate(III)-ion.

Elements that exhibit metallic and non-metallic properties in compounds are called amphoteric, these include elements of the A-groups of the Periodic system - Be, Al, Ga, Ge, Sn, Pb, Sb, Bi, Po, etc., as well as most elements of B- groups - Cr, Mn, Fe, Zn, Cd, Au, etc. Amphoteric oxides are called the same as the main ones, for example:

Amphoteric hydroxides (if the oxidation state of the element exceeds + II) can be in ortho- or (and) meta- form. Here are examples of amphoteric hydroxides:

Amphoteric oxides do not always correspond to amphoteric hydroxides, since when trying to obtain the latter, hydrated oxides are formed, for example:

If several oxidation states correspond to an amphoteric element in compounds, then the amphotericity of the corresponding oxides and hydroxides (and, consequently, the amphotericity of the element itself) will be expressed differently. For low oxidation states, hydroxides and oxides have a predominance of basic properties, and the element itself has metallic properties, so it is almost always a part of cations. For high degrees oxidation, on the contrary, hydroxides and oxides have a predominance of acidic properties, and the element itself has non-metallic properties, so it is almost always included in the composition of anions. Thus, manganese(II) oxide and hydroxide are dominated by basic properties, and manganese itself is part of the 2+ type cations, while acidic properties are dominant in manganese(VII) oxide and hydroxide, and manganese itself is part of the anion of the MnO 4 - . Amphoteric hydroxides with a large predominance of acidic properties are assigned formulas and names based on the model of acid hydroxides, for example HMn VII O 4 - manganese acid.

Thus, the division of elements into metals and non-metals is conditional; between elements (Na, K, Ca, Ba, etc.) with purely metallic properties and elements (F, O, N, Cl, S, C, etc.) with purely non-metallic properties, there is a large group of elements with amphoteric properties.

4. Binary connections

An extensive type of inorganic complex substances is binary compounds. These include, first of all, all two-element compounds (except basic, acidic and amphoteric oxides), for example H 2 O, KBr, H 2 S, Cs 2 (S 2), N 2 O, NH 3, HN 3, CaC 2 , SiH 4 . The electropositive and electronegative components of the formulas of these compounds include single atoms or bonded groups of atoms of the same element.

Multi-element substances, in the formulas of which one of the components contains atoms of several elements that are not interconnected, as well as single-element or multi-element groups of atoms (except hydroxides and salts), are considered as binary compounds, for example CSO, IO 2 F 3, SBrO 2 F, CrO (O 2) 2 , PSI 3 , (CaTi)O 3 , (FeCu)S 2 , Hg(CN) 2 , (PF 3) 2 O, VCl 2 (NH 2). Thus, CSO can be represented as a CS 2 compound in which one sulfur atom is replaced by an oxygen atom.

The names of binary compounds are built according to the usual nomenclature rules, for example:

OF 2 - oxygen difluoride	K 2 O 2 - potassium peroxide
HgCl 2 - mercury(II) chloride	Na 2 S - sodium sulfide
Hg 2 Cl 2 - dirtuti dichloride	Mg 3 N 2 - magnesium nitride
SBr 2 O - sulfur oxide-dibromide	NH 4 Br - ammonium bromide
N 2 O - dinitrogen oxide	Pb (N 3) 2 - lead (II) azide
NO 2 - nitrogen dioxide	CaC 2 - calcium acetylenide

For some binary compounds, special names are used, the list of which was given earlier.

Chemical properties binary compounds are quite diverse, so they are often divided into groups according to the name of the anions, i.e. halides, chalcogenides, nitrides, carbides, hydrides, etc. are considered separately. Among binary compounds, there are also those that have some signs of other types of inorganic substances. So, the compounds CO, NO, NO 2, and (Fe II Fe 2 III) O 4, whose names are built using the word oxide, cannot be attributed to the type of oxides (acidic, basic, amphoteric). Carbon monoxide CO, nitrogen monoxide NO and nitrogen dioxide NO 2 do not have the corresponding acid hydroxides (although these oxides are formed by non-metals C and N), they do not form salts, the anions of which would include atoms C II, N II and N IV. Double oxide (Fe II Fe 2 III) O 4 - oxide of diiron (III) - iron (II), although it contains atoms of the amphoteric element - iron, in the composition of the electropositive component, but in two different oxidation states, as a result of which, when interacting with acid hydroxides, it forms not one, but two different salts.

Binary compounds such as AgF, KBr, Na 2 S, Ba (HS) 2 , NaCN, NH 4 Cl, and Pb (N 3) 2 are built, like salts, from real cations and anions, therefore they are called saline binary compounds (or just salts). They can be considered as products of substitution of hydrogen atoms in the compounds HF, HCl, HBr, H 2 S, HCN, and HN 3 . The latter in an aqueous solution have an acidic function, and therefore their solutions are called acids, for example HF (aqua) - hydrofluoric acid, H 2 S (aqua) - hydrosulfide acid. However, they do not belong to the type of acid hydroxides, and their derivatives do not belong to the salts within the classification of inorganic substances.

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Anyone who went to school remembers that one of the required subjects to study was chemistry. She could like it, or she could not like it - it does not matter. And it is likely that much knowledge in this discipline has already been forgotten and is not applied in life. However, everyone probably remembers the table of chemical elements of D. I. Mendeleev. For many, it has remained a multi-colored table, where certain letters are inscribed in each square, denoting the names of chemical elements. But here we will not talk about chemistry as such, and describe hundreds of chemical reactions and processes, but we will talk about how the periodic table appeared in general - this story will be of interest to any person, and indeed to all those who want interesting and useful information .

A little background

Back in 1668, the outstanding Irish chemist, physicist and theologian Robert Boyle published a book in which many myths about alchemy were debunked, and in which he talked about the need to search for indecomposable chemical elements. The scientist also gave a list of them, consisting of only 15 elements, but allowed the idea that there may be more elements. This became the starting point not only in the search for new elements, but also in their systematization.

A hundred years later, the French chemist Antoine Lavoisier compiled a new list, which already included 35 elements. 23 of them were later found to be indecomposable. But the search for new elements continued by scientists around the world. And leading role the famous Russian chemist Dmitry Ivanovich Mendeleev played in this process - he was the first to put forward the hypothesis that there could be a relationship between the atomic mass of elements and their location in the system.

Thanks to painstaking work and comparison of chemical elements, Mendeleev was able to discover a relationship between elements in which they can be one whole, and their properties are not something taken for granted, but are a periodically repeating phenomenon. As a result, in February 1869, Mendeleev formulated the first periodic law, and already in March, his report “The relationship of properties with the atomic weight of elements” was submitted to the Russian Chemical Society by the historian of chemistry N. A. Menshutkin. Then, in the same year, Mendeleev's publication was published in the journal Zeitschrift fur Chemie in Germany, and in 1871 a new extensive publication of the scientist dedicated to his discovery was published by another German journal, Annalen der Chemie.

Creating a Periodic Table

By 1869, the main idea had already been formed by Mendeleev, and in a fairly short time, but he could not formalize it into any sort of ordered system that clearly displays what was what, for a long time he could not. In one of the conversations with his colleague A. A. Inostrantsev, he even said that everything had already worked out in his head, but he could not bring everything to the table. After that, according to Mendeleev's biographers, he began painstaking work on his table, which lasted three days without a break for sleep. All sorts of ways of organizing elements into a table were sorted out, and the work was complicated by the fact that at that time science did not yet know about all the chemical elements. But, despite this, the table was still created, and the elements were systematized.

Legend of Mendeleev's dream

Many have heard the story that D. I. Mendeleev dreamed of his table. This version was actively distributed by the aforementioned colleague of Mendeleev A. A. Inostrantsev as funny story with which he entertained his students. He said that Dmitry Ivanovich went to bed and in a dream he clearly saw his table, in which all the chemical elements were arranged in the right order. After that, the students even joked that 40° vodka was discovered in the same way. But there were still real prerequisites for the sleep story: as already mentioned, Mendeleev worked on the table without sleep and rest, and Inostrantsev once found him tired and exhausted. In the afternoon, Mendeleev decided to take a break, and some time later, he woke up abruptly, immediately took a piece of paper and depicted a ready-made table on it. But the scientist himself refuted this whole story with a dream, saying: “I’ve been thinking about it for maybe twenty years, and you think: I was sitting and suddenly ... it’s ready.” So the legend of the dream may be very attractive, but the creation of the table was only possible through hard work.

Further work

In the period from 1869 to 1871, Mendeleev developed the ideas of periodicity, to which the scientific community was inclined. And one of the important stages of this process was the understanding that any element in the system should be located based on the totality of its properties in comparison with the properties of other elements. Based on this, and also relying on the results of research in the change of glass-forming oxides, the chemist managed to amend the values ​​of the atomic masses of some elements, among which were uranium, indium, beryllium and others.

Of course, Mendeleev wanted to fill the empty cells that remained in the table as soon as possible, and in 1870 he predicted that chemical elements unknown to science would soon be discovered, atomic masses and whose properties he was able to calculate. The first of these were gallium (discovered in 1875), scandium (discovered in 1879) and germanium (discovered in 1885). Then the forecasts continued to be realized, and eight more new elements were discovered, among them: polonium (1898), rhenium (1925), technetium (1937), francium (1939) and astatine (1942-1943). By the way, in 1900, D. I. Mendeleev and the Scottish chemist William Ramsay came to the conclusion that the elements of the zero group should also be included in the table - until 1962 they were called inert, and after - noble gases.

Organization of the periodic system

The chemical elements in the table of D. I. Mendeleev are arranged in rows, in accordance with the increase in their mass, and the length of the rows is chosen so that the elements in them have similar properties. For example, noble gases such as radon, xenon, krypton, argon, neon, and helium do not easily react with other elements, and also have low chemical activity, which is why they are located in the far right column. And the elements of the left column (potassium, sodium, lithium, etc.) react perfectly with other elements, and the reactions themselves are explosive. To put it simply, within each column, the elements have similar properties, varying from one column to the next. All elements up to No. 92 are found in nature, and with No. 93 artificial elements begin, which can only be created in the laboratory.

In its original version, the periodic system was understood only as a reflection of the order existing in nature, and there were no explanations why everything should be that way. And only when quantum mechanics appeared, the true meaning of the order of elements in the table became clear.

Creative Process Lessons

Talking about what lessons creative process can be drawn from the entire history of the creation of the periodic table of D. I. Mendeleev, we can cite as an example the ideas of the English researcher in the field of creative thinking Graham Wallace and the French scientist Henri Poincaré. Let's take them briefly.

According to Poincaré (1908) and Graham Wallace (1926), there are four main stages in creative thinking:

• Training- the stage of formulating the main task and the first attempts to solve it;
• Incubation- the stage during which there is a temporary distraction from the process, but work on finding a solution to the problem is carried out at a subconscious level;
• insight- the stage at which the intuitive solution is found. Moreover, this solution can be found in a situation that is absolutely not relevant to the task;
• Examination- the stage of testing and implementation of the solution, at which the verification of this solution and its possible further development takes place.

As we can see, in the process of creating his table, Mendeleev intuitively followed these four stages. How effective this is can be judged by the results, i.e. because the table was created. And given that its creation was a huge step forward not only for chemical science, but for the whole of humanity, the above four stages can be applied both to the implementation of small projects and to the implementation of global plans. The main thing to remember is that not a single discovery, not a single solution to a problem can be found on its own, no matter how much we want to see them in a dream and no matter how much we sleep. In order to succeed, whether it is the creation of a table of chemical elements or the development of a new marketing plan, you need to have certain knowledge and skills, as well as skillfully use your potential and work hard.

We wish you success in your endeavors and successful implementation of your plans!

2.1. Chemical language and its parts

Mankind uses many different languages. Except natural languages(Japanese, English, Russian - more than 2.5 thousand in total), there are also artificial languages e.g. Esperanto. Among the artificial languages ​​are languages various Sciences. So, in chemistry, one uses its own, chemical language.
chemical language- a system of symbols and concepts designed for concise, concise and visual recording and transmission of chemical information.
A message written in most natural languages ​​is divided into sentences, sentences into words, and words into letters. If we call sentences, words and letters parts of the language, then we can distinguish similar parts in the chemical language (Table 2).

Table 2.Parts of the chemical language

It is impossible to master any language at once, this also applies to the chemical language. Therefore, for now, you will only get acquainted with the basics of this language: learn some "letters", learn to understand the meaning of "words" and "sentences". At the end of this chapter, you will be introduced to titles chemicals are an integral part of the chemical language. As you study chemistry, your knowledge of the chemical language will expand and deepen.

CHEMICAL LANGUAGE.
1. What artificial languages ​​do you know (except those named in the text of the textbook)?
2. How do natural languages ​​differ from artificial ones?
3. Do you think it is possible to do without the use of chemical language when describing chemical phenomena? If not, why not? If so, what would be the advantages and disadvantages of such a description?

2.2. Symbols of chemical elements

The symbol for a chemical element denotes the element itself or one atom of that element.
Each such symbol is an abbreviated Latin name of a chemical element, consisting of one or two letters of the Latin alphabet (see Appendix 1 for the Latin alphabet). The symbol is capitalized. Symbols, as well as Russian and Latin names of some elements, are given in Table 3. Information about the origin of Latin names is also given there. general rule pronunciation of symbols does not exist, therefore, table 3 also shows the "reading" of a symbol, that is, how this symbol is read in a chemical formula.

It is impossible to replace the name of an element with a symbol in oral speech, and in handwritten or printed texts this is allowed, but not recommended. Currently, 110 chemical elements are known, 109 of them have names and symbols approved by the International Union of Theoretical and Applied Chemistry (IUPAC).
Table 3 provides information on only 33 elements. These are the elements that you will encounter first when studying chemistry. Russian names (in alphabetical order) and symbols of all elements are given in Appendix 2.

Table 3Names and symbols of some chemical elements

Name
	latin		Writing
-	Writing	Origin	-	-
Nitrogen	N itrogenium	From the Greek "giving birth to saltpeter"		"en"
Aluminum	Al uminium	From lat. "alum"		"aluminum"
Argon	Ar gon	From the Greek "inactive"		"argon"
Barium	Ba rium	From the Greek " heavy"		"barium"
Bor	B orum	From Arabic. "white mineral"		"bor"
Bromine	Br omum	From Greek. "malodorous"		"bromine"
Hydrogen	H hydrogenium	From Greek. "giving birth to water"		"ash"
Helium	He lium	From the Greek " Sun"		"helium"
Iron	Fe rrum	From lat. "sword"		"ferrum"
Gold	Au rum	From lat. "burning"		"aurum"
Iodine	I odum	From Greek. " violet"		" iodine"
Potassium	K alium	From Arabic. "lye"		"potassium"
Calcium	Ca lcium	From lat. "limestone"		"calcium"
Oxygen	O xygenium	From the Greek "producer of acids"		" about"
Silicon	Si licium	From lat. "flint"		"silicium"
Krypton	kr ypton	From the Greek "hidden"		"krypton"
Magnesium	M a g nesium	From the name peninsulas of Magnesia		"magnesium"
Manganese	M a n ganum	From Greek. "purifying"		"manganese"
Copper	Cu prum	From the Greek name about. Cyprus		"cuprum"
Sodium	Na trium	From Arabic, "detergent"		"sodium"
Neon	Ne on	From the Greek " new"		"neon"
Nickel	Ni colum	From him. "copper of St. Nicholas"		"nickel"
Mercury	H ydrar g yrum	Lat. "liquid silver"		"hydrargyrum"
Lead	P lum b um	From lat. the name of the alloy of lead and tin.		"plumbum"
Sulfur	S sulfur	From Sanskrit "flammable powder"		"es"
Silver	A r g entum	From the Greek " light coloured"		"argentum"
Carbon	C arboneum	From lat. " coal"		"ce"
Phosphorus	P hosphorus	From Greek. "carrying light"		"pe"
Fluorine	F luorum	From lat. verb "to flow"		"fluorine"
Chlorine	Cl orum	From Greek. "greenish"		"chlorine"
Chromium	C h r omium	From Greek. " dye"		"chrome"
Cesium	C ae s ium	From lat. "sky blue"		"cesium"
Zinc	Z i n cum	From him. "tin"		"zinc"

2.3. Chemical formulas

Used to refer to chemicals chemical formulas.

For molecular substances, the chemical formula can also denote one molecule of this substance.
Information about a substance can be different, so there are different types of chemical formulas.
Depending on the completeness of information, chemical formulas are divided into four main types: protozoa, molecular, structural and spatial.

Subscripts in the simplest formula do not have a common divisor.
Index "1" is not put in formulas.
Examples of the simplest formulas: water - H 2 O, oxygen - O, sulfur - S, phosphorus oxide - P 2 O 5, butane - C 2 H 5, phosphoric acid - H 3 PO 4, sodium chloride (table salt) - NaCl.
The simplest formula of water (H 2 O) shows that the water contains the element hydrogen(H) and element oxygen(O), and in any portion (a portion is a part of something that can be divided without losing its properties.) of water, the number of hydrogen atoms is twice the number of oxygen atoms.
Number of particles, including number of atoms, denoted by the Latin letter N. Denoting the number of hydrogen atoms - N H , and the number of oxygen atoms is N O , we can write that

Or N H: N O=2:1.

The simplest formula of phosphoric acid (H 3 PO 4) shows that phosphoric acid contains atoms hydrogen, atoms phosphorus and atoms oxygen, and the ratio of the numbers of atoms of these elements in any portion of phosphoric acid is 3:1:4, that is

NH: N P: N O=3:1:4.

The simplest formula can be drawn up for any individual chemical substance, and for a molecular substance, in addition, molecular formula.

Examples of molecular formulas: water - H 2 O, oxygen - O 2, sulfur - S 8, phosphorus oxide - P 4 O 10, butane - C 4 H 10, phosphoric acid - H 3 PO 4.

Nonmolecular substances do not have molecular formulas.

The sequence of writing the symbols of elements in the simplest and molecular formulas is determined by the rules of the chemical language, which you will learn as you study chemistry. The sequence of characters does not affect the information conveyed by these formulas.

Of the signs reflecting the structure of substances, we will use so far only valence stroke("dash"). This sign shows the presence between the atoms of the so-called covalent bond(what kind of connection is this and what are its features, you will soon find out).

In the water molecule, the oxygen atom is connected by simple (single) bonds with two hydrogen atoms, and the hydrogen atoms are not connected to each other. This is clearly shown by the structural formula of water.

Another example: the sulfur molecule S 8 . In this molecule, 8 sulfur atoms form an eight-membered cycle in which each sulfur atom is connected to two other atoms by simple bonds. Compare the structural formula of sulfur with the three-dimensional model of its molecule shown in fig. 3. Please note that the structural formula of sulfur does not convey the shape of its molecule, but only shows the sequence of connecting atoms by covalent bonds.

The structural formula of phosphoric acid shows that in the molecule of this substance one of the four oxygen atoms is bonded only to the phosphorus atom double bond, and the phosphorus atom, in turn, is connected to three more oxygen atoms by simple bonds. Each of these three oxygen atoms, in addition, is connected by a simple bond with one of the three hydrogen atoms present in the molecule./p>

Compare the following three-dimensional model of the methane molecule with its spatial, structural and molecular formula:

In the spatial formula of methane, wedge-shaped valence strokes, as if in perspective, show which of the hydrogen atoms is "closer to us" and which is "farther from us".

Sometimes the spatial formula indicates the bond lengths and the values ​​of the angles between the bonds in the molecule, as shown in the example of the water molecule.

Nonmolecular substances do not contain molecules. For the convenience of carrying out chemical calculations in a nonmolecular substance, the so-called formula unit.

Examples of the composition of the formula units of some substances: 1) silicon dioxide (quartz sand, quartz) SiO 2 - the formula unit consists of one silicon atom and two oxygen atoms; 2) sodium chloride (common salt) NaCl - the formula unit consists of one sodium atom and one chlorine atom; 3) iron Fe - a formula unit consists of one iron atom. Like a molecule, a formula unit is the smallest portion of a substance that retains its chemical properties.

Table 4

Information Conveyed by Different Types of Formulas

Formula Type	The information passed by the formula.
Protozoa Molecular Structural Spatial		Atoms of which elements make up the substance. The ratios between the numbers of atoms of these elements. The number of atoms of each of the elements in the molecule. Types of chemical bonds. The sequence of connecting atoms by covalent bonds. Multiplicity of covalent bonds. Mutual arrangement atoms in space. Bond lengths and bond angles (if specified).

Let us now consider, with examples, what information formulas of different types give us.

1. Substance: acetic acid. The simplest formula is CH 2 O, the molecular formula is C 2 H 4 O 2, the structural formula

The simplest formula tells us that
1) in the composition acetic acid includes carbon, hydrogen and oxygen;
2) in this substance, the number of carbon atoms is related to the number of hydrogen atoms and to the number of oxygen atoms, as 1:2:1, that is N H: N C: N O = 1:2:1.
Molecular formula adds that
3) in the molecule of acetic acid - 2 carbon atoms, 4 hydrogen atoms and 2 oxygen atoms.
Structural formula adds that
4, 5) in the molecule, two carbon atoms are linked by a single bond; one of them, in addition, is associated with three hydrogen atoms, with each single bond, and the other with two oxygen atoms, with one double bond, and with the other a single bond; the last oxygen atom is also linked by a simple bond to the fourth hydrogen atom.

2. Substance: sodium chloride. The simplest formula is NaCl.
1) Sodium chloride contains sodium and chlorine.
2) In this substance, the number of sodium atoms is equal to the number of chlorine atoms.

3. Substance: iron. The simplest formula is Fe.
1) The composition of this substance includes only iron, that is, it is a simple substance.

4. Substance: trimetaphosphoric acid . The simplest formula is HPO 3, the molecular formula is H 3 P 3 O 9, the structural formula

1) The composition of trimetaphosphoric acid includes hydrogen, phosphorus and oxygen.
2) N H: N P: N O = 1:1:3.
3) A molecule consists of three hydrogen atoms, three phosphorus atoms and nine oxygen atoms.
4, 5) Three phosphorus atoms and three oxygen atoms, alternating, form a six-membered cycle. All links in the cycle are simple. Each phosphorus atom, in addition, is associated with two more oxygen atoms, with one - a double bond, and the other - a simple one. Each of the three oxygen atoms linked by simple bonds to phosphorus atoms is also linked by a simple bond to a hydrogen atom.

Phosphoric acid - H 3 PO 4(another name is phosphoric acid) is a transparent colorless crystalline substance of a molecular structure, melting at 42 o C. This substance is very soluble in water and even absorbs water vapor from the air (hygroscopically). Phosphoric acid is produced in large quantities and are used primarily in the production of phosphate fertilizers, as well as in the chemical industry, in the production of matches and even in construction. In addition, phosphoric acid is used in the manufacture of cement in dental technology, is part of many medicines. This acid is cheap enough that in some countries, such as the United States, very pure phosphoric acid, highly diluted with water, is added to refreshments to replace expensive citric acid.

Methane - CH 4. If you have a gas stove at home, then you encounter this substance daily: natural gas, which burns in the burners of your stove, is 95% methane. Methane is a colorless and odorless gas with a boiling point of -161 o C. When mixed with air, it is explosive, which explains the explosions and fires that sometimes occur in coal mines (another name for methane is firedamp). The third name of methane - swamp gas - is due to the fact that bubbles of this particular gas rise from the bottom of swamps, where it is formed as a result of the activity of certain bacteria. In industry, methane is used as a fuel and raw material for the production of other substances. Methane is the simplest hydrocarbon. This class of substances also includes ethane (C 2 H 6), propane (C 3 H 8), ethylene (C 2 H 4), acetylene (C 2 H 2) and many other substances.

Table 5.Examples of formulas of different types for some substances-

"Chemical element - sulfur" - Natural intergrowth of crystals of native sulfur. Molecules with closed (S4, S6) chains and open chains are possible. Sulfur ores are mined different ways- depending on the conditions of occurrence. Natural sulfur minerals. We must not forget about the possibility of its spontaneous combustion. Open pit mining. Walking excavators remove layers of rocks under which ore lies.

"Questions on chemical elements" - Can be stable and radioactive, natural and artificial. Associated with a change in the number of energy levels in the main subgroups. 8. What element does not have a permanent "registration" in the Periodic system? They are in constant motion. Tellurium, 2) selenium, 3) osmium, 4) germanium. Where does arsenic accumulate?

"H2O and H2S" - Sulfate ion. Y=? K K2 \u003d 1.23 10? 13 mol / l. Preparation: Na2SO3 + S = Na2SO3S (+t, aq. solution). In aqueous solution: +Hcl (ether). Vitriols MSO4 5(7)H2O (M – Cu, Fe, Ni, Mg …). Sulphuric acid H2SO4. Structure of SO32– and HSO3– anions. = y. The SO3 molecule is non-polar and diamagnetic. ? . Hydrosulfite ion: tautomerism.

"Periodic Table of Chemical Elements" - 8. How many electrons can be in the third energy level? Arrange the elements in ascending order of metallic properties. Name of the country: "Chemical elementary". Poems by Stepan Shchipachev. A. 17 B. 35 C. 35.5 D. 52 6. How many electrons revolve around the nucleus in a fluorine atom?

"Calcium Ca" - Ca compounds. Chemical properties of Ca. Physical properties of Ca. Calcium is one of the common elements. Application. Obtaining calcium in industry. Calcium Ca. Describe physical properties Ca. Finding in nature. Task to repeat. Calcium Ca is a silvery white and rather hard metal, light.

"The element phosphorus" - Phosphorus is the 12th most abundant element in nature. Interaction with simple substances - non-metals. interaction with metals. To bind calcium compounds, quartz sand is added. When white phosphorus is heated in an alkali solution, it disproportionates. Phosphorus. black phosphorus.

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