Video tutorial: Classes of inorganic compounds
Lecture: Classification of inorganic substances. Nomenclature of inorganic substances (trivial and international)
Let's start with a simple division of inorganic substances into simple and complex ones. Simple molecules consist of atoms of one element, and complex ones from atoms of several elements. Simple ones are divided into metals and non-metals. Complex, in turn, are subdivided into oxides, hydroxides, salts.
Oxides
Oxidesare complex substances consisting of two elements, one of which is oxygen with an oxidation state of -2.
Oxides are subdivided into salt-forming (basic, acidic, amphoteric), non-salt-forming, and salt-like (double).
Basic oxides possess basic properties and are able to form typical metals with oxidation states +1, +2, (Li 2 O, MgO, CaO, CuO).
Acidic oxides possess acidic properties and are capable of forming non-metals with an oxidation state of more than +2. Metals with degrees from +5 to +7 (SO 2, SeO 2, P 2 O 5, As 2 O 3, CO 2, SiO 2, CrO 3, and Mn 2 O 7) are also formed. Exception: oxides NO 2 and ClO 2 do not have corresponding acidic hydroxides. Despite this, they are considered acidic.
Amphoretic oxides possess both basic and acidic properties. They are formed by amphoteric metals having an oxidation state of +2, +3, +4 (Cr 2 O 3, Al 2 O 3, GeO 2, SnO 2. In this group of oxides with an oxidation state of +2, there are only 4: ZnO, PbO, SnO , BeO.
Non-salt-forming oxides they have neither basic nor acidic properties. These include oxides of non-metals with oxidation states +1, +2. There are 4 of them: CO, NO, N 2 O, SiO.
Salt oxides formed by two elements with different oxidation states. For example, magnetic iron ore FeO Fe 2 O 3, which, when interacting with acids, forms two salts: FeO Fe 2 O 3 + 4H 2 SO 4 → FeSO 4 + Fe 2 (SO 4) 3 + 4H 2 O
Hydroxides
Hydroxides are complex substances consisting of oxides and water, which have a hydroxyl group (OH -).
They are classified into bases, oxygenated acids, and amphoteric hydroxides.
- Foundations- metal hydroxides with oxidation states +1, +2, showing basic properties and consisting of metal ions and hydroxide - OH - ions.
For example:
- sodium hydroxide - Na + OH,
- calcium hydroxide - Ca +2 (OH) 2,
- iron hydroxide - Fe +3 (OH) 3.
- Acidic hydroxides (oxygenated acids) - hydroxides of non-metals and metals with oxidation states of +5, +6, exhibiting acidic properties, consisting of hydroxonium - H 3 O + cations and an acid residue.
For example:
- Nitric acid - HNO 3,
- Sulfuric acid - H 2 SO 4.
- Amphoteric hydroxides - metal hydroxides with an oxidation state of +2, +3, +4, exhibiting both acidic and basic properties. In this group of hydroxides with an oxidation state of +2, there are only 4: Zn (OH) 2, Pb (OH) 2, Sn (OH) 2, Be (OH) 2.
Salt
Salt- complex chemicals formed by metal atoms associated with acidic residues.
For example:
- Sodium chloride - NaCl,
- Sodium sulfate - Na 2 SO 4,
- Calcium chloride - CaCl 2,
- Calcium sulfate - CaSO 4.
There are the following types of salts:
Medium salts- salts containing metal atoms and acid residue. For example: calcium nitrate Ca (NO 3) 2, lead sulfate PbSO 4, sodium carbonate Na 2 CO 3, etc.
Acidic salts- salts containing metal atoms, acid residue and hydrogen. Metal atoms are formed by neutralizing a base with an excess of acid. To form the name of any acidic salt, it is necessary to add the prefix hydro - or dihydro - to the name of the salt. The prefix depends on the number of hydrogen atoms that make up the acid salt. Example: KHCO 3 - potassium bicarbonate, KH 2 PO 4 - potassium dihydrogen phosphate. It is also necessary to remember that acidic salts are capable of forming two or more basic acids. They can be both oxygen-containing and anoxic acids.
Basic salts- salts containing metal atoms, acid residue and hydroxyl group (OH−). To determine the name of the basic salt, it is necessary to add the prefix hydroxo or dihydroxo to the name of the common salt. The prefix will depend on the number of OH - groups that make up the salt. For example, (CuOH) 2 CO 3 is copper (II) hydroxycarbonate. You should also know that basic salts form bases containing two or more hydroxyl groups.
Double salts- salts containing cations of two metals and an acidic residue. For example, aluminum sulfate - potassium KAl (SO 4) 2 12H 2 O
Mixed salts- salts containing anions of two metals and an acidic residue. For example, copper (II) dihydroxocarbonate Cu 2 (OH) 2 CO 3.
Hydrated salts- salts containing crystallization water molecules. For example, sodium sulfate decahydrate Na 2 SO 4 10H 2 O
The construction of formulas and names is determined by chemical trivial and international nomenclature. Trivial names are historical traditional names.
Formula | Trivial names | International titles |
Salt | Sodium chloride |
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Sodium hydroxide | Sodium hydroxide |
|
Soda, soda ash | Sodium carbonate |
|
Baking soda | Sodium bicarbonate |
|
Liquid glass | Sodium silicate |
|
Quicklime | Calcium oxide |
|
Slaked lime | Calcium hydroxide |
|
Limestone, chalk, marble | Calcium carbonate |
|
Calcium fluoride |
||
Graphite, diamond | ||
Carbon monoxide | Carbon monoxide |
|
Carbon dioxide | Carbon dioxide |
|
Caustic potassium | Potassium hydroxide |
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Potassium carbonate |
||
Potassium nitrate | Potassium nitrate |
|
Bertoleth's salt | Potassium chlorate |
|
Yellow blood salt | Potassium hexacyanoferrate (II) |
|
Red blood salt | Potassium hexacyanoferrate (III) |
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Burnt Magnesia Magnesium Oxide | Magnesium oxide |
|
Magnesite Magnesium Carbonate | Magnesium carbonate |
|
Iron (III) oxide |
||
Iron pyrite, pyrite | Iron disulfide |
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Fe 4 3 | Prussian blue | Iron (III) hexacyanoferrate (II) |
inkstone | Iron (II) sulfate heptahydrate |
|
Copper luster | Copper (I) sulphide |
|
Cu 2 (OH) 2 CO 3 | Hydroxomed (II) carbonate |
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Copper sulfate | Copper (II) Sulfate Pentahydrate |
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Currently, more than 500 thousand inorganic compounds are known, it is almost impossible to know their formulas, names, and even more so properties. In order to make it easier to navigate in a huge variety of chemicals, all substances are divided into separate classes, including compounds that are similar in structure and properties.
Initially, all chemicals are divided into simple and complex.
Simple substances are classified into metals and non-metals.
In addition to typical metals and non-metals, there is a large group of substances with intermediate properties, they are called metalloids. .
Complex substances are classified into four classes of chemical compounds: oxides, bases, acids and salts. . This classification was developed by outstanding chemists of the 18th-19th centuries Antoine Laurent Lavoisier, Mikhail Vasilyevich Lomonosov, Jones Jacob Berzelius, John Dalton.
In fig. 8 shows the most important classes of inorganic compounds.
Figure 8 - The most important classes of inorganic compounds
Hydroxides are a type of complex substance that contains atoms of some element E (except for fluorine and oxygen) and OH hydroxyl groups; general formula of hydroxides E (OH) n, where n= 1 ÷ 6. Form of hydroxides E (OH) n called ortho-form; at n> 2 the hydroxide can also be found in meta-form, which includes, in addition to the 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 groups with opposite chemical properties: acidic and basic hydroxides.
Acidic hydroxides contain hydrogen atoms that can be replaced by metal atoms if the rule of stoichiometric valence is observed. Most acidic hydroxides are found in meta-form, and hydrogen atoms in the formulas of acidic 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 acidic hydroxides is H NS EO at, where the electronegative component EO y x - called acid residue. If not all hydrogen atoms are replaced by a metal, then they remain in the acid residue.
The names of common acidic hydroxides consist of two words: their own name with the ending "ah" and the group word "acid".
The names of acids and acid residue are presented in table. Appendix A.
The names of acid residues are used to construct the names of salts.
Basic hydroxides contain hydroxide ions, which can be replaced by acidic residues if the rule of stoichiometric valence is observed. All major hydroxides are found in ortho-form; their general formula is M (OH) n, where n= 1.2 (less often 3.4) and M n+ - metal cation.
Examples of formulas and names of basic hydroxides:
The most important chemical property of basic and acidic hydroxides is their interaction with each other with the formation of salts ( salt formation reaction), for example:
Ca (OH) 2 + H 2 SO 4 = CaSO 4 + 2H 2 O
Ca (OH) 2 + 2H 2 SO 4 = Ca (HSO 4) 2 + 2H 2 O
2Ca (OH) 2 + H 2 SO 4 = Ca 2 SO 4 (OH) 2 + 2H 2 O
Salt- the type of complex substances, which include M cations n+ and acidic residues.
Salts with general formula M NS(EO at)n are called average salts, and salts with unsubstituted hydrogen atoms, - sour salts. Sometimes salts also contain hydroxide - and / or oxide - ions; such salts are called the main salts.
Here are examples and names of salts:
Acidic and basic salts can be converted to medium salts by interaction with the corresponding basic and acidic hydroxide, for example:
Ca (HSO 4) 2 + Ca (OH) = CaSO 4 + 2H 2 O
Ca 2 SO 4 (OH) 2 + H 2 SO 4 = 2CaSO 4 + 2H 2 O
There are also salts containing two different cations: they are often called double salts , for example:
Acid and basic oxides
E oxides NS O at- products of complete dehydration of hydroxides:
Acid hydroxides (H 2 SO 4, H 2 CO 3) are answered acid oxides (SO 3, CO 2), and basic hydroxides (NaOH, Ca (OH) 2) - basic oxides (Na 2 O, CaO), and the oxidation state of the element E does not change when going from hydroxide to oxide.
An example of formulas and names of oxides:
Acidic 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 = 2NaNO 3 + H 2 O
3CaO + 2H 3 PO 4 = Ca 3 (PO 4) 2 + 3H 2 O
La 2 O 3 + 3SO 3 = La 2 (SO 4) 3
Amphoteric oxides and hydroxides
Amphotericity hydroxides and oxides - a chemical property consisting in the formation of two series 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 = 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 = 2NaAlO 2 + H 2 O
So, hydroxide and aluminum oxide in reactions (a) exhibit the properties major hydroxides and oxides, i.e. react with acidic hydroxides and oxide, forming the corresponding salt - aluminum sulfate Al 2 (SO 4) 3, while in reactions (b) they also exhibit the 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 element aluminum 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 included in the electronegative component of the salt formula (AlO 2 -).
If these reactions take place in an aqueous solution, then the composition of the formed 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, the complex ions 3+ are highlighted in square brackets - the cation of hexaaquaaluminium (III), - - 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 table - Be, Al, Ga, Ge, Sn, Pb, Sb, Bi, Po, etc., as well as most of the elements 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 found in ortho- or (and) meta- form.
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 the amphoteric element in the compounds corresponds to several oxidation states, then the amphotericity of the corresponding oxides and hydroxides (and, consequently, the amphotericity of the element itself) will be expressed in different ways. 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 included in the composition of cations. For high oxidation states, on the contrary, acidic properties predominate in hydroxides and oxides, and non-metallic properties in the element itself, therefore it is almost always included in the composition of anions.
Oxides- compounds of elements with oxygen, the oxidation state of oxygen in oxides is always -2.
Basic oxides form typical metals with S.O. + 1, + 2 (Li 2 O, MgO, CaO, CuO, etc.).
Acidic oxides form non-metals with S.O. more +2 and metals with S.O. from +5 to +7 (SO 2, SeO 2, P 2 O 5, As 2 O 3, CO 2, SiO 2, CrO 3 and Mn 2 O 7). Exception: oxides NO 2 and ClO 2 do not have corresponding acidic hydroxides, but they are considered acidic.
Amphoteric oxides formed by amphoteric metals with S.O. + 2, + 3, + 4 (BeO, Cr 2 O 3, ZnO, Al 2 O 3, GeO 2, SnO 2 and PbO).
Non-salt-forming oxides- oxides of non-metals with CO + 1, + 2 (CO, NO, N 2 O, SiO).
Foundations (basic hydroxides ) - complex substances that consist of a metal ion (or ammonium ion) and a hydroxyl group (-OH).
Acid hydroxides (acids)- complex substances that consist of hydrogen atoms and an acidic residue.
Amphoteric hydroxides formed by elements with amphoteric properties.
Salt- complex substances formed by metal atoms combined with acidic residues.
Medium (normal) salts- all hydrogen atoms in acid molecules are replaced by metal atoms.
Acidic salts- hydrogen atoms in acid are partially replaced by metal atoms. They are obtained by neutralizing the base with an excess of acid. To correctly name sour salt it is necessary to add the prefix hydro or dihydro to the name of the normal salt, depending on the number of hydrogen atoms that make up the acid salt.
For example, KHCO 3 - potassium bicarbonate, KH 2 PO 4 - potassium dihydrogen phosphate
It must be remembered that acidic salts can form only two or more basic acids.
Basic salts- the hydroxyl groups of the base (OH -) are partially substituted by acidic residues. To call basic salt, it is necessary to add the prefix hydroxo or dihydroxo to the name of the normal salt, depending on the number of OH - groups that make up the salt.
For example, (CuOH) 2 CO 3 is copper (II) hydroxycarbonate.
It must be remembered that basic salts can form only bases containing two or more hydroxyl groups.
Double salts- they contain two different cations, obtained by crystallization from a mixed solution of salts with different cations, but the same anions. For example, KAl (SO 4) 2, KNaSO 4.
Mixed salts- they contain two different anions. For example, Ca (OCl) Cl.
Hydrate salts (crystal hydrates) - they include molecules of crystallization water. Example: Na 2 SO 4 10H 2 O.
Trivial names for commonly used inorganic substances:
| Formula | Trivial name |
| NaCl | halite, rock salt, table salt |
| Na 2 SO 4 * 10H 2 O | Glauber's salt |
| NaNO 3 | Sodium, Chilean nitrate |
| NaOH | caustic soda, caustic soda, caustic soda |
| Na 2 CO 3 * 10H 2 O | crystalline soda |
| Na 2 CO 3 | Soda ash |
| NaHCO 3 | baking soda |
| K 2 CO 3 | potash |
| KOH | caustic potassium |
| KCl | potassium salt, sylvin |
| KClO 3 | berthollet's salt |
| KNO 3 | Potash, Indian saltpeter |
| K 3 | red blood salt |
| K 4 | yellow blood salt |
| KFe 3+ | Prussian blue |
| KFe 2+ | turnboolean blue |
| NH 4 Cl | Ammonia |
| NH 3 * H 2 O | ammonia, ammonia water |
| (NH 4) 2 Fe (SO 4) 2 | Mohr's salt |
| CaO | quicklime (burnt) lime |
| Ca (OH) 2 | slaked lime, lime water, milk of lime, lime paste |
| CaSO 4 * 2H 2 O | Gypsum |
| CaCO 3 | marble, limestone, chalk, calcite |
| CaHRO 4 × 2H 2 O | Precipitate |
| Ca (H 2 RO 4) 2 | double superphosphate |
| Ca (H 2 PO 4) 2 + 2CaSO 4 | simple superphosphate |
| CaOCl 2 (Ca (OCl) 2 + CaCl 2) | bleaching powder |
| MgO | magnesia |
| MgSO 4 * 7H 2 O | English (bitter) salt |
| Al 2 O 3 | corundum, bauxite, alumina, ruby, sapphire |
| C | diamond, graphite, soot, coal, coke |
| AgNO 3 | lapis |
| (CuOH) 2 CO 3 | malachite |
| Cu 2 S | copper luster, chalcocite |
| CuSO 4 * 5H 2 O | copper sulfate |
| FeSO 4 * 7H 2 O | inkstone |
| FeS 2 | pyrite, iron pyrite, sulfur pyrite |
| FeCO 3 | siderite |
| Fe 2 O 3 | red iron ore, hematite |
| Fe 3 О 4 | magnetic iron ore, magnetite |
| FeO × nH 2 O | brown iron ore, limonite |
| H 2 SO 4 × nSO 3 | oleum SO 3 solution in H 2 SO 4 |
| N 2 O | laughing gas |
| NO 2 | brown gas, fox tail |
| SO 3 | sulfuric gas, sulfuric anhydride |
| SO 2 | sulfur dioxide, sulfur dioxide |
| CO | carbon monoxide |
| CO 2 | carbon dioxide, dry ice, carbon dioxide |
| SiO 2 | silica, quartz, river sand |
| CO + H 2 | water gas, synthesis gas |
| Pb (CH 3 COO) 2 | lead sugar |
| PbS | lead luster, galena |
| ZnS | zinc blende, sphalerite |
| HgCl 2 | corrosive sublimate |
| HgS | cinnabar |
The classification of inorganic substances is based on their degradability. Simple substances consisting of atoms of only one chemical element (O 2, H 2, Mg) do not decay. Complex substances consisting of atoms of two or more elements (CO 2, H 2 SO 4, NaOH, KCl) are easily decomposed.
Simple
Classification of classes of inorganic substances includes:
- metals - elements with thermal and electrical conductivity, high ductility, malleability, metallic luster;
- non-metals - more fragile than metals, elements that do not have electrical conductivity and exhibit oxidizing properties.
Rice. 1. Scheme for the classification of inorganic substances.
Metals are located in the lower left corner of the periodic table, nonmetals in the upper right corner and include noble gases.
Rice. 2. The location of metals and non-metals in the periodic table.
Many simple chemical elements have allotropy - the property of forming several simple substances. For example, when one more atom is attached to oxygen, a simple substance ozone (O 3) is formed, carbon, depending on the number of atoms, forms graphite, coal or diamond.
Complex
Complex substances are classified into the following classes:
- oxides - consist of two elements, one of which is oxygen;
- acid - consist of hydrogen atoms and an acid residue;
- foundations - consist of a metal and one or more hydroxyl groups;
- salt - consist of a metal and an acidic residue.
Separately, amphoteric hydroxides are isolated, which exhibit the properties of acids and bases. These are solids that are weak electrolytes. These include metal hydroxides with oxidation states +3 and +4. Exceptions are Be (OH) 2, Zn (OH) 2, Sn (OH) 2, Pb (OH) 2.
A more detailed classification of complex substances is presented in the table with examples.
|
View |
Nomenclature |
Chemical properties |
Example |
|
Oxides - E x O y |
Element oxide (oxidation state) |
Basic oxides are distinguished, which form salts when interacting with acids, and acid oxides, which form acids when interacting with bases. Separately isolated amphoteric oxides interacting with acids and bases (salt is formed) |
Na 2 O - sodium oxide, Fe 2 O 3 - iron (III) oxide, N 2 O 5 - nitric oxide (V) |
|
Bases - Me (OH) x |
Metal hydroxide (oxidation state) |
In accordance with the solubility, alkalis and bases insoluble in water are isolated. Alkalis interact with non-metals and acidic oxides. Insoluble bases interact with acids and can decompose at high temperatures |
Fe (OH) 2 - iron (II) hydroxide, Cu (OH) 2 - copper (II) hydroxide, NaOH - sodium hydroxide |
|
Acids - H n Ac |
It is read depending on the acid residue |
They interact with metals located to the left of hydrogen in a number of activities, with oxides, salts. Capable of decomposition at high temperatures |
H 2 SO 4 - sulfuric acid, HCl - hydrochloric acid, HNO 3 - nitric acid |
|
Salts - Me x (Ac) y |
Acidic metal residue (oxidation state) |
Reacts with acids, alkalis, metals and salts |
Na 2 SO 4 - sodium sulfate, CaCO 3 - calcium carbonate, KCl - potassium chloride |
Rice. 3. List of names of acids.
Genetic relationships between classes are based on the mutual transformation of substances. During chemical reactions, atoms move from one substance to another, forming genetic series (series of transformations). Metal, upon addition of oxygen, forms an oxide, which, upon interaction with water, turns into a base. An acidic oxide is formed from a non-metal, which, interacting with water, forms an acid. Any genetic line ends in salt.
What have we learned?
Inorganic substances include simple and complex compounds. Simple substances are made up of atoms of the same element. These include metals and non-metals. Complex compounds include substances composed of several elements. These include oxides, acids, bases, salts, and amphoteric hydroxides. All substances are genetically related. A more complex substance can be obtained from a simple substance. The most complex substances are salts.
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On this moment more than five hundred thousand inorganic compounds have been identified. The classification and nomenclature of inorganic substances is an important issue that allows you to understand the variety of compounds.
Historical reference
In the 18th-19th centuries, Antoine Lavoisier, Mikhail Lomonosov, John Dalton proposed the first classification and nomenclature of inorganic substances. Simple ones were distinguished and the First group was divided into metals and non-metals. A group of compounds was also isolated that had intermediate properties called metalloids. This division formed the basis of the modern classification.
At the moment, there are four classes. Let's take a closer look at each of these classes.
Oxides
They are polyatomic compounds, which consist of two elements, the second in them is always an oxygen ion in the oxidation state -2. The classification and nomenclature of inorganic substances involves the division of the class of oxides into three groups:
- basic;
- amphoteric;
- acidic
Classification
The first group consists of metal compounds (with minimum oxidation states) with oxygen. For example, MgO is magnesium oxide. Among the main chemical properties of this compound, one can note their interaction with acidic oxides, acids, and more active metals.
Oxygen compounds of non-metals, as well as metallic elements with oxidation states from +4 to +7. For example, this group includes MnO 2, CO 2. Among the typical ones, we single out the interaction with water (a weak carbonic acid is formed), basic oxides, and soluble bases (alkalis).
Amphoteric (transitional) oxides are called compounds of metals with an oxidation state of +3 (as well as beryllium oxide, zinc oxide), which are able to interact with both acids and alkalis.
Oxides are subdivided into salt-forming and non-salt-forming. The first group corresponds to acids or bases in which the basic element retains its oxidation state. The non-salt-forming group is small in number, its representatives are not able to form salts. For example, among the non-salt-forming oxides, there are: N 2 O, NO, SiO, CO.
Hydroxides
The classification and nomenclature of inorganic substances involves the allocation of a class of hydroxides. They are called complex substances, which contain atoms of some element, as well as OH hydroxyl groups. This class is subdivided into two large groups:
- grounds;
- acid
Acids contain several hydrogen atoms that can be replaced by metal atoms, subject to the rules of stoichiometric valence. Many are in meta-form, and the hydrogen atoms in them are located at the beginning of the formula. They have the general form HxEOy, where the second part is called the acid residue. Classification and their nomenclature is considered within the framework of the school chemistry course. Sulfuric acid - sulfates, nitric acid - nitrates, carbonic acid - carbonates.
Depending on the number of hydrogen atoms, the following groups are distinguished:
- monobasic;
- dibasic;
- tribasic acids
The bases in their composition contain metal cations and OH, which are capable of being replaced by acid residues in chemical reactions, subject to the rules of stoichiometric valence.
The bases are in the ortho form, have the general formula M (OH) n, with n = 1 or 2. When the compounds of this group are named, the corresponding metal is added to the hydroxide.
Among the main chemical properties possessed by representatives of this cash register of inorganic substances, it is necessary to note their reaction with acids, the reaction products are water and salt.
For example, in the reaction of sodium hydroxide with hydrochloric acid, the products are water and sodium chloride.
Depending on the solubility in water, soluble bases (alkalis) and insoluble hydroxides are isolated. The first group includes hydroxyl compounds of metals of the first and second groups of the main subgroups (alkali and alkaline earth metals).
For example, NaOH is alkali (sodium hydroxide); Fe (OH) 2 - iron II hydroxide (insoluble compound).
Salt
What else does the classification and nomenclature of inorganic substances include? Tasks for students in grades 8-9 involve dividing the proposed list of compounds into separate classes: oxides, bases, acids, salts.
Salts are complex substances in which metal cations and acid residue anions are present. Medium salts have the general formula Mx (EOy) n. An example of this group is Ca 3 (PO 4) 2 - calcium phosphate.
If hydrogen cations also appear in the composition, the salts are called acidic, and the presence of hydroxyl groups is characteristic of basic salts. For example, NaHCO 3 is sodium bicarbonate, and CaOHCl is calcium hydroxychloride.
Those salts, which contain cations of two different metals, are called double.
Complex salts are complex compounds that contain a complexing agent and ligands. In high school, the classification and nomenclature of inorganic substances is considered. Theory complex compounds studied as part of a specialized course in general chemistry. Questions regarding the nomenclature and chemical properties of complex salts are not included in the test questions of the unified state examination in chemistry for the course high school.
Conclusion
How is the classification and nomenclature of inorganic substances used in the school curriculum? Briefly, groups of substances are considered in the framework of the programs of the eighth and ninth grades, and they are studied in more detail in the course of general chemistry of grade 11. Tasks relating to the classification of inorganic compounds, comparison of the chemical properties of compounds with the proposed products are included in the tests of the final certification in chemistry (USE) for eleventh grade graduates. In order to successfully cope with them, students must have basic knowledge of the classification of inorganic compounds, the skills of comparing the proposed substances with the chemical properties of the entire class.