What character do oxides exhibit? Coordination numbers of metals in oxide crystals

Instructions

You need to have a good understanding of how properties change chemical elements depending on their location in the D.I. table. Mendeleev. So repeat, electronic structure atoms (the oxidation state of elements depends on it) and so on.

Without resorting to practical actions, you will be able to establish the nature of the oxide using only periodic table. After all, it is known that in periods, in the direction from left to right alkaline properties oxides are replaced by amphoteric ones, and then by acidic ones. For example, in III period sodium oxide (Na2O) has the main properties, the compound of aluminum with oxygen (Al2O3) has the character, and chlorine oxide (ClO2) has the character.

Keep in mind that in the main subgroups the alkaline properties of the oxides increase from top to bottom, and the acidity, on the contrary, weakens. Thus, in group I, cesium oxide (CsO) has a stronger basicity than lithium oxide (LiO). In group V, nitrogen oxide (III) is acidic, and oxide (Bi2O5) is already basic.

First, take two clean test tubes. From the bottles, using a chemical spatula, pour a little CaO into one and P2O5 into the other. Then pour 5-10 ml of distilled water into both reagents. Stir with a glass rod until the powder is completely dissolved. Dip pieces of litmus paper into both test tubes. There, the indicator will become blue, which is evidence of the basic nature of the compound under study. In a test tube with phosphorus (V) oxide, the paper will turn red, therefore P2O5 – .

Since zinc oxide is insoluble in water, react with an acid and a hydroxide to prove that it is amphoteric. In both cases, ZnO crystals will enter chemical reaction. For example:
ZnO + 2KOH = K2ZnO2 + H2O
3ZnO + 2H3PO4→ Zn3(PO4)2↓ + 3H2O

Please note

Remember, the nature of the properties of the oxide directly depends on the valency of the element included in its composition.

Useful advice

Do not forget that there are also so-called indifferent (non-salt-forming) oxides that do not react under normal conditions with either hydroxides or acids. These include non-metal oxides with valence I and II, for example: SiO, CO, NO, N2O, etc., but there are also “metallic” ones: MnO2 and some others.

Sources:

• basic character oxides

Oxide calcium- This is ordinary quicklime. But, despite such a simple nature, this substance is very widely used in economic activity. From construction, as a base for lime cement, to cooking, as food additives E-529, oxide calcium finds application. Both in industrial and at home conditions you can obtain oxide calcium from carbonate calcium reaction thermal decomposition.

You will need

• Calcium carbonate in the form of limestone or chalk. Ceramic crucible for annealing. Propane or acetylene torch.

Instructions

Prepare the crucible for annealing the carbonate. Mount it firmly on fireproof stands or special fixtures. The crucible must be firmly installed and, if possible, secured.

Grind the carbonate calcium. Grinding must be done for better heat transfer inside. It is not necessary to grind limestone or chalk into dust. It is enough to produce coarse, heterogeneous grinding.

Fill the annealing crucible with ground carbonate calcium. Do not fill the crucible completely, since when carbon dioxide is released, some of the substance may be thrown out. Fill the crucible about a third full or less.

Start heating the crucible. Install and secure it well. Carry out smooth heating of the crucible with different sides to avoid its destruction due to uneven thermal expansion. Continue heating the crucible on the gas burner. After some time, the thermal decomposition of carbonate will begin calcium.

Wait complete passage thermal decomposition. During the reaction, the upper layers of the substance in the crucible may not warm up well. They can be mixed several times with a steel spatula.

Video on the topic

Please note

Be careful when working with a gas burner and a heated crucible. During the reaction, the crucible will be heated to temperatures above 1200 degrees Celsius.

Useful advice

Instead of trying to make it yourself large quantities calcium oxide (for example, for the subsequent production of lime cement), it is better to buy the finished product on specialized trading platforms.

Sources:

• Write down the reaction equations that can be used to

According to generally accepted views, acids are complex substances, consisting of one or more hydrogen atoms that can be replaced by metal atoms and acid residues. They are divided into oxygen-free and oxygen-containing, monobasic and polybasic, strong, weak, etc. How to determine whether a particular substance has acid properties?

You will need

• - indicator paper or litmus solution;
• - hydrochloric acid (preferably diluted);
• - sodium carbonate powder (soda ash);
• - a little silver nitrate in solution;
• - flat-bottomed flasks or beakers.

Instructions

The first and simplest test is a test using indicator litmus paper or litmus solution. If the paper strip or solution has pink tint, which means that the substance under study contains hydrogen ions, and this sure sign acids. You can easily understand that the more intense the color (up to red-burgundy), the more acidic.

There are many other ways to check. For example, you are given the task of determining whether a clear liquid is hydrochloric acid. How to do this? You know the reaction to chloride ion. It is detected by adding even the smallest amounts of lapis solution - AgNO3.

Pour some of the test liquid into a separate container and drop in a little lapis solution. In this case, a “curdy” white precipitate of insoluble silver chloride will instantly form. That is, there is definitely a chloride ion in the molecule of the substance. But maybe it’s not, after all, but a solution of some kind of chlorine-containing salt? For example, sodium chloride?

Remember another property of acids. Strong acids(and salt, of course, is one of them) can displace weak acids from them. Place a little soda powder - Na2CO3 - in a flask or beaker and slowly add the liquid to be tested. If there is a hissing sound immediately and the powder literally “boils”, there will be no doubt left - it is hydrochloric acid.

Why? Because this reaction is: 2HCl + Na2CO3 = 2NaCl + H2CO3. Carbonic acid is formed, which is so weak that it instantly decomposes into water and carbon dioxide. It was his bubbles that caused this “boiling and hissing.”

Video on the topic

Please note

Hydrochloric acid, even diluted, is a caustic substance! Remember safety precautions.

Useful advice

Under no circumstances should you resort to taste tests (if your tongue tastes sour, it means there is acid). At the very least, it can be very dangerous! After all, many acids are extremely caustic.

Sources:

• how acid properties change in 2019

Phosphorus is a chemical element with the 15th serial number in the Periodic Table. It is located in its V group. A classic non-metal discovered by the alchemist Brand in 1669. There are three main modifications of phosphorus: red (part of the mixture for lighting matches), white and black. At very high pressures(about 8.3 * 10^10 Pa), black phosphorus transforms into another allotropic state (“metallic phosphorus”) and begins to conduct current. phosphorus in various substances?

Instructions

Remember, degree . This is a value corresponding to the charge of an ion in a molecule, provided that the electron pairs that carry out the bond are shifted towards a more electronegative element (located to the right and higher in the Periodic Table).

You also need to know the main condition: the amount electric charges of all ions that make up the molecule, taking into account the coefficients, must always be equal to zero.

The oxidation state does not always quantitatively coincide with the valence. Best example– carbon, which in organics always has a value of 4, and the oxidation state can be equal to -4, and 0, and +2, and +4.

What is the oxidation state in the phosphine molecule PH3, for example? All things considered, this question is very easy to answer. Since hydrogen is the very first element in the Periodic Table, by definition it cannot be located there “to the right and higher” than . Therefore, it is phosphorus that will attract hydrogen electrons.

Each hydrogen atom, having lost an electron, will turn into a positively charged oxidation ion +1. Therefore, the total positive charge is +3. This means, taking into account the rule stating that the total charge of the molecule equal to zero, the oxidation state of phosphorus in a phosphine molecule is -3.

Well, what is the oxidation state of phosphorus in the oxide P2O5? Take the Periodic Table. Oxygen is located in group VI, to the right of phosphorus, and also higher, therefore, it is definitely more electronegative. That is, the oxidation state of oxygen in this compound will have a minus sign, and phosphorus will have a plus sign. What are these degrees so that the molecule as a whole is neutral? You can easily see that the least common multiple of the numbers 2 and 5 is 10. Therefore, the oxidation state of oxygen is -2, and phosphorus is +5.

Video on the topic

Oxides are complex substances consisting of two elements, one of which is oxygen (K - O - K; Ca « O; 0 « Sb0, etc.). All oxides are divided into non-salt and salt-forming. The few non-salt-forming oxides do not react with either acids or bases. These include nitric oxide (I) N20, nitric oxide (I) N0, etc. Salt-forming oxides are divided into basic, acidic and amphoteric. Basic are oxides that form salts when reacting with acids or acidic oxides. So, for example: CuO + H2S04 - CuS04 + H20, MgO + CO2 = MgC03. Only metal oxides can be basic. However, not all metal oxides are basic - many of them are amphoteric or acidic (for example, Cr2O3 is amphoteric, and CrO3 is acid oxide). Some of the basic oxides dissolve in water, forming the corresponding bases: Na20 + H20 - 2NaOH. Acidic oxides are those that form salts when reacting with bases or basic oxides. So, for example: S02 + 2K0H - K2S03 + H20, P4O10 + bCaO = 2Ca3(P04)2. Oxides of typical nonmetals, as well as oxides of a number of metals in higher degrees oxidation (B203; N205; Mn207). Many acid oxides (also called anhydrides) combine with water to form acids: N203 + H20 - 2HN02. Amphoteric oxides are those that form salts when reacting with both acids and bases. Amphoteric oxides include: ZnO; A1203; Sg203; Mn02; Fe2O3, etc. For example, the amphoteric nature of zinc oxide manifests itself when it interacts with both hydrochloric acid and potassium hydroxide: ZnO + 2HC1 = ZnCl2 + H20, ZnO + 2 KOH = K2Zn02 + H20, ZnO + 2KOH + H20 - K2. The amphoteric nature of oxides, insoluble in acid solutions, and hydroxides is proven using more complex reactions. Thus, calcined oxides of aluminum and chromium (III) are practically insoluble in acid solutions and alkalis. In the reaction of their fusion with potassium disulfate, the main properties of the oxides appear: A1203 + 3K2S207 « 3K2S04 + A12(S04)3. When fused with hydroxides, the acidic properties of the oxides are revealed: A1203 + 2KOH - 2KA102 4-H20. Thus, amphoteric oxides have the properties of both basic and acidic oxides. Note that for different amphoteric oxides the duality of properties can be expressed to varying degrees. For example, zinc oxide dissolves equally easily in both acids and alkalis, i.e., in this oxide the basic and acidic functions are expressed to approximately the same extent. Iron (III) oxide - Fe203 - has predominantly basic properties; It exhibits acidic properties only when interacting with alkalis at high temperatures: Fe2O3 + 2NaOH « 2NaFe02 + H20. Methods for obtaining oxides [T] Preparation from simple substances: 2Ca + 02 = 2CaO. \2\ Decomposition of complex substances: a) decomposition of oxides 4Cr03 = 2Cr203 + 302!; b) decomposition of hydroxides Ca(OH)2 = CaO + H20; c) decomposition of acids H2CO3 = H2O + CO2T; d) decomposition of salts Interaction of acids - oxidizers with metals and non-metals: Cu + 4HN03(Koim, = Cu(N03)2 + 2N02t + 2H20, C + 2H2S04 (koid, - CO2| + 2S02t + 2H20. Displacement of a volatile oxide by a less volatile one at high temperature: Na2CO„ + Si02 = Na2Si03 + C02 f. fusion Questions and tasks for independent solution L Indicate which ones are not organic matter are called oxides. What underlies the separation of oxides into salt- and non-salt-forming ones; According to what chemical properties salt-forming oxides are divided into basic, acidic and amphoteric. 2. Determine what type the following oxides are: CaO, SiO, BaO, SiO2, S03, P4O10, FeO, CO, ZnO, Cr2O3, NO. 3. Indicate which bases correspond to the following oxides: Na20, CaO, A1203, CuO, FeO, Fe203. 4. Indicate which acid anhydrides the following oxides are: C02, S02, S03, N203, N205, Cr03, P4O10. 5. Indicate which of the following oxides are soluble in water: CaO, CuO, Cr203, Si02, FeO, K20, CO, N02, Cr03, ZnO, A1203. 6. Indicate which of the following substances carbon monoxide (IV) will react with: S02, KOH, H20, Ca(OH)2, CaO. 7. Write reaction equations reflecting the properties of the following main oxides: FeO, Cs20, HgO, Bi203. Write reaction equations proving the acidic nature of the following oxides: S03, Mn207, P4O10, Cr03, Si02. 9. Show how you can prove the amphoteric nature of the following oxides: ZnO, Al2O3, Cr2O3. 10. Using the example of reactions for the production of sulfur (IV) oxide, indicate the main methods for producing oxides. 11. Complete the equations of the following chemical reactions, reflecting the methods for producing oxides: 1) Li + 02 -> 2) Si2H6 + 02 - 3) PbS + 02 4) Ca3P2 + 02 5) Al(OH)3 - 6) Pb(N03) 2 U 7) HgCl2 + Ba(OH)2 8) MgC03 + HN03 - 9) Ca3(P04)2 + Si02 - 10) C02 + C £ 11) Cu + HNO3(30o/o) £ 12) C + H2S04 ( conc) 12. Determine the formula of the oxide, formed by the element with an oxidation state of +2, if it is known that 3.73 g of hydrochloric acid was required to dissolve 4.05 g of it. Answer: C&O. 13. When carbon monoxide (IV) reacted with sodium hydroxide, 21 g of sodium bicarbonate was formed. Determine the volume of carbon monoxide (IV) and the mass of sodium hydroxide consumed to produce the salt. Answer: 5.6 l C02; 10 g NaOH. 14. During the electrolysis of 40 mol of water, 620 g of oxygen were released. Determine the oxygen yield. Answer: 96.9%. Determine the mass of acidic and intermediate salts that can be obtained by reacting 5.6 liters of SO2 with potassium hydroxide. What is the mass of alkali in each individual case? Answer: 30 g KHS03; 39.5 g K2S03; 14 g KOH; 28 g CON. 16. Define the simplest formula a compound containing 68.4% chromium and 31.6% oxygen. Answer: SG203. 17. Determine the oxidation degree of manganese in the oxide if it is known that 1 g of manganese contains 1.02 g of oxygen. Answer: +7. 18. In the oxide of a monovalent element, the mass fraction of oxygen is 53.3%. Name the element. Answer: lithium. 19. Determine the mass of water required to dissolve 188 g of potassium oxide if you received a solution with mass fraction KOH 5.6%. Answer: 3812 g. 20. When 32 g of iron (III) oxide is reduced with carbon, 20.81 g of iron are formed. Determine the iron yield. Answer: 90%.

Oxides (oxides) are chemical compounds consisting of two elements, one of which is .

Non-salt-forming are so called because during chemical reactions with other substances they do not form salts. These include H 2 O, carbon monoxide CO, nitrogen oxide NO. Among salt-forming oxides, basic, acidic and amphoteric oxides are distinguished (Table 2).
Main are called, which correspond to those belonging to the class of bases. Basic ones react with acids to form salt and water.
Basic oxides are metal oxides. They are characterized by an ionic type of chemical bond. For metals that make up basic oxides, the value is no higher than 3. Typical examples of basic oxides are calcium oxide CaO, barium oxide BaO, copper oxide CuO, iron oxide Fe 2 O 8, etc.

The names of the main oxides are relatively simple. If a metal that is part of a basic oxide has a constant , its oxide is called oxide, for example, sodium oxide Na 2 O, potassium oxide K 2 O, magnesium oxide MgO, etc. If the metal has a variable, the oxide in which it exhibits the highest valence is called an oxide, and the oxide in which it exhibits the lowest valency is called an oxide. called nitrous oxide, for example Fe 2 O 3 - iron oxide, FeO - ferrous oxide, CuO - copper oxide, Cu 2 O - copper oxide.

Write down the definition of oxides in your notebook.

Oxides are called acidic; they correspond to acids and react with bases to form salt and water.

Acidic oxides- These are mainly oxides of non-metals. Their molecules are built according to covalent type communications. The valency of nonmetals in oxides is usually equal to 3 or higher. Typical examples of acidic oxides are sulfur dioxide SO 2, carbon dioxide CO 2, sulfuric anhydride SO 3.
The name of an acidic oxide is often based on the number of oxygen atoms in its molecule, for example CO 2 - carbon dioxide, SO 3 - sulfur trioxide, etc. The name “anhydride” (devoid of water) is no less often used in relation to acidic oxides, for example CO 2 - carbonic anhydride, SO 3 - sulfuric anhydride, P 2 O 5 - phosphoric anhydride, etc. You will find an explanation for these names when studying the properties of oxides.

By modern system names, all oxides are called the single word “oxide”, and if an element can have different meanings valency, they are indicated by a Roman numeral next to each other in parentheses. For example, Fe 2 O 3 is iron (III) oxide, SO 3 is (VI).
Using the periodic table, it is convenient to determine the nature of the higher oxide of an element. It is safe to say, for example, that the higher oxides of the elements of the main subgroups of groups I and II are typical basic oxides, since these elements are typical. Higher oxides of elements of the main subgroups V, VI, VII of groups are typical acid oxides, since the elements that form them are non-metals:
It often happens that those located in group IV-VII form higher oxides of an acidic nature, for example, they form higher oxides Mn 2 O 7 and CrO 3, which are acidic and are respectively called manganese and chromic anhydride.

■ 46. Indicate among the substances listed below those that are oxides: CaO; FeCO3; NaNO3; SiO2; CO 2; Ba(OH) 2 ; R 2 O 5; H2CO3; PbO; HNO3; FeO; SO 3; MgCO 3 ; MnO; CuO; Na 2 O; V 2 O 6; Ti02. Which group of oxides do they belong to? Name the given oxides according to the modern system. ()

Chemical properties of oxides

Despite the fact that the molecules of many oxides are built of the ionic type, they are not electrolytes, since they do not dissolve in water in the sense in which we understand dissolution. Some of them can only interact with water, forming soluble products. But then it is not the oxides that dissociate, but the products of their interaction with water. Thus, electrolytic dissociation oxides are not affected. But when melting, they can undergo thermal dissociation - decomposition into ions in the melt.
It is most convenient to first consider the properties of basic and acidic oxides.
All basic oxides are solid, odorless, and can have different colors: magnesium oxide is white, iron oxide is rusty-brown, copper oxide is black.

By physical properties among acidic oxides there are solid (silicon dioxide SiO 2, phosphoric anhydride P 2 O 5, sulfuric anhydride SO 3), gaseous (sulfur dioxide SO 2, carbon dioxide CO 2). Sometimes anhydrides have color and odor.
The chemical properties of basic and acidic oxides are very different from each other. Considering them, we will always draw a parallel between basic and acidic oxides.

Amphoteric oxides are those oxides that have dual properties and behave as basic under some conditions and as acidic under others. Amphoteric oxides include oxides Al 2 O 3 , ZnO and many others.

Let us consider the properties of amphoteric oxides using the example of zinc oxide ZnO. Amphoteric oxides usually correspond to weak ones, which practically do not dissociate, therefore amphoteric oxides do not interact with water. However, due to their dual nature, they can react with both acids and alkalis:
ZnO + H 2 SO 4 = ZnSO 4 + H 2 O

ZnO + 2H + + SO 2 4 - = Zn 2+ + SO 2 4 - + H2O
ZnO + 2H + = Zn 2+ + H 2 O
In this reaction, zinc oxide behaves as a basic
oxide.
If zinc oxide enters an alkaline environment, then it behaves like an acidic oxide, which corresponds to the acid H 2 ZnO 2 (the formula is easy to find if you mentally add water H 2 O to the formula of zinc oxide). Therefore, the equation for the reaction of zinc oxide with alkali is written as follows:
ZnO + 2NaOH = Na 2 ZnO 2 + H 2 O
sodium zincate (soluble salt)
ZnO + 2Na + + 2OH - = 2Na + + ZnO 2 2 - + H 2 O
Abbreviated:
ZnO + 2OH - = ZnO 2 2 - + H 2 O

■ 47. What amount of carbon dioxide will be produced when 6 g of coal is burned? If you have forgotten how to solve chemical equation problems, refer to Appendix 1 and then solve this problem. ()
48. How many gram molecules of copper oxide are required to react with 49 g of sulfuric acid? (You can learn about what a gram molecule is and how to use this concept in calculations by reading Appendix 1 on page 374).
49. How much sulfuric acid can be obtained by reacting 4 gram molecules of sulfuric anhydride with water?
50. What volume of oxygen is consumed to burn 8 g of sulfur? (The problem is solved using the concept of “volume of a gram-molecule of a gas.”).
51. How to make transformations:

Write the reaction equations in molecular and total ionic form.

52. What oxides are obtained from the decomposition of the following hydroxides: CuONH. Fe(OH)3, H2SiO3, Al(OH)3, H2SO3? Explain with reaction equations.
53. Which of the following substances will barium oxide react with: a) , b) , c) potassium oxide; d) copper oxide, e) calcium hydroxide; f) phosphoric acid; g) sulfur dioxide? Write the formulas of all the listed substances. Where possible, write the reaction equations in molecular, full ionic, and reduced ionic form.
54. Suggest a method for producing copper oxide CuO based on copper sulfate, water and sodium metal. ()

Determining the nature of the properties of higher oxides using the periodic table

elements of D. I. Mendeleev
Knowing that the most typical metals are located at the beginning of the period, we can predict that the higher oxides of elements of the main subgroups of groups I and II should have basic properties. Some exception is represented by , the oxide of which is amphoteric in nature. At the end of the period there are nonmetals, the higher oxides of which must have acidic properties. Depending on the position of the elements in the periodic table, the corresponding elements can also be basic, acidic or amphoteric in nature. Based on this, we can make well-founded assumptions about the composition and properties of the oxides and hydroxides of certain elements.

■ 55. Write the formulas of higher oxides of strontium and indium. Can they react with sulfuric acid and sodium hydroxide? Write the reaction equations. ()
56. Write the formulas of rubidium, barium, lanthanum hydroxides.
57. How do reactions occur between rubidium hydroxide and nitric acid, between barium hydroxide and hydrochloric acid? Write the reaction equations.
58. Knowing that the formula of the highest selenium oxide is SeO 3, write the equations for the reactions of selenium anhydride with calcium hydroxide and sodium oxide.
59. Write the equations for the reactions of selenic acid with rubidium hydroxide, potassium oxide, barium hydroxide, calcium oxide.
60. Using the periodic table of elements, find the formulas of telluric acid (No. 52), perchloric acid (No. 17), germanic acid (No. 32), chromic acid (No. 24).
61. Write the equation for the reaction between rubidium hydroxide and antimony acid (No. 37, No. 51). ()

In addition to oxides and hydroxides, many elements can form compounds with hydrogen under common name hydrides. The specific properties of hydrides depend on the relative electronegativity of hydrogen and the element with which it combines.
Hydrogen compounds with typical metals, such as (NaH), (KH), (CaH 2), etc., are formed according to the type of ionic bond, and this is negative ion, and the metal is positive. Metal hydrides are solid, resemble salts, and have an ionic crystal lattice.
Hydrogen compounds with non-metals have more or less polar molecules, for example HCl, H 2 O, NH 3, etc., and are gaseous substances.
During education covalent bonds elements with hydrogen number electron pairs equal to the number of electrons missing to complete the outer electron layer of these elements (octet). This number does not exceed 4, therefore, volatile hydrogen compounds can only be formed by elements of the main subgroups of groups IV-VII, which have a pronounced electronegativity compared to hydrogen. The valence of an element in a volatile hydrogen compound can be calculated by subtracting from the number 8 the number of the group in which the element is located.
Elements side subgroups IV-VII groups of volatile hydrides do not form, since these are elements belonging to d-family having 1 - 2 electrons on the outer layer, which indicates weak electronegativity.

■ 62. Determine the valency in volatile hydrogen compounds elements silicon, phosphorus, oxygen, sulfur, bromine, arsenic, chlorine. ()
63. Write the formulas of volatile hydrogen compounds of arsenic (No. 33), bromine (No. 35), carbon (No. 6), selenium (No. 34).
64. Will they form volatile compounds with hydrogen the elements listed below: a) (No. 41); b) (No. 83); c) iodine (No. 53); d) (No. 56); e) (No. 81); f) (No. 32); g) (No. 8); (No. 43); i) (No. 21); j) (No. N); l) (No. 51)? ()

If so, write the corresponding formulas.
The same principle underlies the compilation of formulas for binary compounds, i.e., compounds consisting of two elements, using the periodic system of elements. In this case, the element with the least metallic properties, i.e., more electronegative, will exhibit the same valence as in volatile hydrogen compounds, and the element with less electronegativity will exhibit the same valence as in the higher oxide. When writing the formula for a binary compound, the symbol of the less electronegative element is placed first, and the more negative element is placed second. So, when writing, for example, the formula of lithium sulfide, we determine that as a metal exhibits lower electronegativity, its valency is the same as in the oxide, i.e. 1, equal to the group number. exhibits greater electronegativity and, therefore, its valence is 8-6 = 2 (the group number is subtracted from 8). Hence the formula Li 2 S.

■ 65. Based on the position of the elements in the periodic table, write the formulas for the following compounds:
a) tin chloride (No. 50, No. 17);
b) indium bromide (No. 49, No. 35);
c) cadmium iodine (No. 48, iodine No. 53);
d) nitrogen or lithium nitride (No. 3, No. 7);
e) strontium fluoride (No. 38, No. 9);
f) sulphide, or cadmium sulfide (No. 48, No. 16).
g) aluminum bromide (No. 13, No. 35). ()

Using the periodic table of elements, you can write formulas for salts of oxygen acids and create chemical equations. For example, to write the formula of barium chromate, you need to find the formula of the higher chromium oxide CrO 3, then find chromic acid H 2 CrO 4, then find the valence of barium (it is equal to 2 - according to the group number) and compose the formula BaCrO 4.

■ 66. Write the formulas for calcium permanganate and rubidium arsenic acid.
67. Write following equations reactions:
a) cesium hydroxide + perchloric acid;
b) thallium hydroxide + phosphoric acid;
c) strontium hydroxide + ;
d) rubidium oxide + sulfuric anhydride;
e) barium oxide + carbonic anhydride;
e) strontium oxide + sulfuric anhydride;
g) cesium oxide + silicon anhydride;
h) lithium oxide + phosphoric acid;
i) beryllium oxide + arsenic acid;
j) rubidium oxide + chromic acid;
l) sodium oxide + periodic acid;
l) strontium hydroxide + aluminum sulfate;
m) rubidium hydroxide + gallium chloride;
o) strontium hydroxide + arsenic anhydride;
n) barium hydroxide + selenium anhydride. ()

The meaning of the periodic law and the periodic system of elements of D. I. Mendeleev in the development of chemistry

The periodic table is a system of elements, and all living and inanimate nature. Therefore, this is not only the main chemical law, but also a fundamental law of nature that has philosophical significance.
The discovery of the periodic law had a huge impact on the development of chemistry and has not lost its significance to this day. Using the periodic system of elements, D.I. Mendeleev was able to check and correct the atomic weights of a number of elements, for example, osmium, iridium, platinum, gold, etc. Based on the periodic system, D.I. Mendeleev, for the first time in the history of chemistry, successfully predicted the discovery of new elements.
In the 60s of the last century, some elements, such as (No. 21), (No. 31), (No. 32), etc., were not yet known. Nevertheless, D.I. Mendeleev left for them free seats in the periodic table, because he was convinced that these elements would be discovered, and predicted their properties with exceptional accuracy. For example, the properties of the element, the existence of which D.I. Mendeleev predicted in 1871 and which he named eca-silicon, coincide with the properties of germanium, discovered in 1885 by Winkler.
Currently, knowing about the structure of atoms and molecules, we can characterize in more detail the properties of elements based on their position in the periodic table according to the following plan.
1. The position of the element in the table of D.I. Mendeleev. 2. Charge of the nucleus of an atom and total number electrons.
3. Number energy levels and the distribution of electrons on them.
4. Electronic configuration atom. 5. Nature of properties (metallic, non-metallic, etc.).
6. Higher valence in oxide. The formula of the oxide, the nature of its properties, reaction equations confirming the assumed properties of the oxide.

7. Hydroxide. Properties of higher hydroxide. Reaction equations confirming the expected nature of the properties of the hydroxide.
8. Possibility of formation of volatile hydride. Hydride formula. Valency of the element in the hydride.
9. Possibility of chloride formation. Chloride formula. The type of chemical bond between the element and chlorine.
Mendeleev predicted 11 elements, and all of them were discovered: in 1875 by P. Lecoq de Boisbaudran, in 1879 by L. Nilsson and P. Kleve -, in 1898 by Marie Sklodowska-Curie and Pierre - (No. 84 ) and (No. 88), in 1899 by A. Debiern - (No. 89, predicted ecalantane). In 1917 O. Hahn and L. Meitner (Germany) discovered (No. 91), in 1925 V. Noddack, I. Noddack and O. Berg - (No. 75), in 1937 C. Perrier and E . Segre (Italy) -technetium (No. 43), in 1939 M. Perey (France) - (No. 87), and in 1940 D. Corson, K. McKenzie and E. Segre (USA) - (No. 85).

Some of these elements were discovered during the lifetime of D.I. Mendeleev. At the same time, using the periodic system, D.I. Mendeleev checked the atomic weights of many already known elements and made corrections to them. Experimental verification of these amendments confirmed the correctness of D.I. Mendeleev. The periodic system was logically completed by the discovery in 1894 by Ramsey of inert gases, which had not been in the periodic system until that year.
The discovery of the periodic law directed scientists to search for the causes of periodicity. It contributed to revealing the essence serial numbers groups and periods, i.e. the study internal structure an atom considered indivisible. explained a lot, but at the same time presented scientists with a number of problems, the solution of which led to the study internal structure atom, explaining differences in the behavior of elements in chemical reactions. The discovery of the periodic law created the prerequisites for the artificial production of elements.
The periodic table, whose centenary we celebrated in 1969, is still a subject of study.
The ideas of D.I. Mendeleev marked the beginning of a new period in the development of chemistry.

Biography of D. I. Mendeleev

D. I. Mendeleev was born on February 8, 1834 in Tobolsk, where his father was the director of the gymnasium. At the Tobolsk gymnasium, where he entered in 1841, D. I. Mendeleev showed great interest in natural sciences. In 1849 he entered the Faculty of Science and Mathematics of the St. Petersburg Pedagogical Institute. After the death of his parents and sister, D.I. Mendeleev was left alone. Nevertheless, he continued his education with great persistence. At the institute, professor of chemistry A. A. Voskresensky had a huge influence on him. Along with chemistry, D.I. Mendeleev was interested in mechanics, mineralogy, and botany.
In 1855, D.I. Mendeleev graduated from the institute with a gold medal and was sent as a natural science teacher to Simferopol, since intensive studies at the institute undermined his health and doctors recommended that he go south. Then he moved to Odessa. Here, as a teacher at the first Odessa gymnasium, he worked on the “hydrate” theory of solutions and on master's thesis“On specific volumes.” In 1856, D.I. Mendeleev brilliantly passed his master's exams and defended his dissertation. The originality and courage of thought in this work aroused admiring responses in the press and great interest in the scientific world.
Soon, 23-year-old D.I. Mendeleev became an associate professor and received the right to

give lectures at St. Petersburg University. In an extremely poorly equipped university laboratory, he continued his research, but work in such conditions could not satisfy the scientist, and in order to continue it more successfully, he was forced to leave for Germany. Having purchased the necessary reagents, glassware and instruments, he created a laboratory at his own expense and began to study the nature of gases and the issues of converting them into liquid state and intermolecular adhesion of liquids. D. I. Mendeleev was the first to talk about critical temperatures for gases and experimentally identified many of them, thereby proving that at a certain temperature all gases can be converted into liquids.
In Germany, D.I. Mendeleev became close to many remarkable Russian scientists, who were also forced to work abroad. Among them were N. N. Beketov, A. P. Borodin, I. M. Sechenov and others. In 1860, D. I. Mendeleev took part in the I international congress chemists in Karlsruhe.

In 1861 he returned to St. Petersburg and began teaching the course organic chemistry at the university. Here for the first time he created a textbook of organic chemistry, reflecting latest achievements this science. In this textbook, D.I. Mendeleev considered all processes from a purely materialistic point of view, criticizing the “vitalists”, adherents of the so-called vitality, thanks to which, as they believed, life exists and organic substances are formed.
DI. Mendeleev first drew attention to isomerism - a phenomenon in which organic substances, having the same composition, have different properties. Soon this phenomenon was explained by A.M. Butlerov.
After defense in 1864 doctoral dissertation on the topic “On the combination of alcohol with water” D. I. Mendeleev in 1865 became a professor at St. Petersburg Institute of Technology and university.

In 1867, he received an invitation to France to organize the Russian pavilion at the World Industrial Exhibition. He outlined his impressions of the trip in his work “About modern development some chemical production as applied to Russia regarding the World Exhibition of 1867.”
In this work, the author expressed many valuable thoughts, in particular, he touched upon the issue of poor use in Russia natural resources, mainly oil, and the need to build chemical plants producing locally the raw materials that Russia imports from abroad.

With his research in the field of hydration theory of solutions, D.I. Mendeleev, following Lomonosov, laid the foundation new area science - physical chemistry.
In 1867, D.I. Mendeleev was elected head of the department of inorganic chemistry at St. Petersburg University, which he headed for 28 years. His lectures were extremely popular among students of all faculties and all courses. At the same time, D.I. Mendeleev led a great community work aimed at strengthening and developing Russian science. On his initiative, the Russian Physico-Chemical Society was founded in 1868, to which D.I. Mendeleev first sent his report “An experiment on a system of elements based on their atomic weight and chemical similarity.” This was the famous one, on the basis of which D.I. Mendeleev wrote his famous work"Fundamentals of Chemistry".

The periodic law and the periodic system of elements allowed D.I. Mendeleev to predict the discovery of new elements and describe their properties with great accuracy. These elements were discovered during the life of D.I. Mendeleev and brought great fame to the periodic law and its discoverer.
But the glory of D. I. Mendeleev and his progressive ideas made a completely different impression on the reactionary circles of the St. Petersburg Academy of Sciences. Despite his enormous services to science, D.I. Mendeleev was not elected to the Academy. This attitude towards the great scientist caused a storm of protest throughout the country. The Russian Physics and Chemical Society elected D.I. Mendeleev as an honorary member. In 1890, D.I. Mendeleev had to leave his job at the university. Nevertheless, his scientific and practical activities didn't crumble. He was constantly occupied with issues of economic development of the country, participated in the preparation of customs tariffs, and worked in the Chamber of Weights and Measures. But in all his endeavors, he invariably encountered opposition from the tsarist government. D. I. Mendeleev died in 1907. In his person, the world lost a brilliant, versatile scientist who put forward a number of ideas that were destined to be realized only in our time.

D.I. Mendeleev was an ardent champion of the development of domestic industry. Especially great attention he devoted to the development of the oil industry. Even then he spoke about the construction of oil pipelines and chemical oil refining. But oil owners preferred to exploit oil fields predatorily.
For the first time, D.I. Mendeleev put forward the idea of ​​underground gasification, which was developed only in our time coal, which was highly appreciated back in 1913. V. I. Lenin, Necessities of creation chemical industry in Russia, D.I. Mendeleev devoted a number of his works, but its development became possible only in Soviet times: D.I. Mendeleev developed new methods of exploration iron ores, methods of mining coal from deep-lying seams, put forward a project for the development of the North, was interested in the problems of aeronautics and the study upper layers atmosphere. D.I. Mendeleev proposed a method for producing smokeless gunpowder, which the tsarist government ignored, but which was used by the American military department.

Checking the completion of tasks and answers to questions for Ch. I 1. 16; 61; 14; 42. 2. Difference in atomic weight...

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Chemical compounds consisting of oxygen and any other element of the periodic table are called oxides. Depending on their properties, they are classified into basic, amphoteric and acidic. The nature of the oxides can be determined theoretically and practically.

You will need

• - periodic system;
• - laboratory glassware;
• - chemical reagents.

Instructions

You need to have a good understanding of how the properties of chemical elements change depending on their location in the D.I. table. Mendeleev. So repeat periodic law, electronic structure of atoms (the degree of oxidation of elements depends on it) and so on.

Without any hands-on work, you can establish the nature of the oxide using only the periodic system. After all, it is known that in periods, in the direction from left to right, the alkaline properties of oxides change to amphoteric, and then to acidic. For example, in the III period, sodium oxide (Na2O) exhibits basic properties, the compound of aluminum with oxygen (Al2O3) is amphoteric in nature, and chlorine oxide (ClO2) is acidic.

Keep in mind that in the main subgroups the alkaline properties of the oxides increase from top to bottom, and the acidity, on the contrary, weakens. Thus, in group I, cesium oxide (CsO) has a stronger basicity than lithium oxide (LiO). In group V, nitrogen oxide (III) is acidic, and bismuth oxide (Bi2O5) is already basic.

Another way to determine the nature of the oxides. Let's say the task is given to experimentally prove the basic, amphoteric and acidic properties of calcium oxide (CaO), 5-valent phosphorus oxide (P2O5(V)) and zinc oxide (ZnO).

First, take two clean test tubes. From the bottles, using a chemical spatula, pour a little CaO into one and P2O5 into the other. Then pour 5-10 ml of distilled water into both reagents. Stir with a glass rod until the powder is completely dissolved. Dip pieces of litmus paper into both test tubes. Where calcium oxide is located, the indicator will turn blue, which is proof of the basic nature of the compound being tested. In a test tube with phosphorus (V) oxide, the paper will turn red, therefore P2O5 is an acidic oxide.

Since zinc oxide is insoluble in water, react with an acid and a hydroxide to prove that it is amphoteric. In both cases, ZnO crystals will enter into a chemical reaction. For example:
ZnO + 2KOH = K2ZnO2 + H2O
3ZnO + 2H3PO4 Zn3(PO4)2 + 3H2O

Please note

Remember, the nature of the properties of the oxide directly depends on the valency of the element included in its composition.

Useful advice

Do not forget that there are also so-called indifferent (non-salt-forming) oxides that do not react under normal conditions with either hydroxides or acids. These include non-metal oxides with valence I and II, for example: SiO, CO, NO, N2O, etc., but there are also “metallic” ones: MnO2 and some others.

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Chemical compounds consisting of oxygen and any other element of the periodic table are called oxides. Depending on their properties, they are classified into basic, amphoteric and acidic. The nature of the oxides can be determined theoretically and practically.

You will need

• - periodic system;
• - laboratory glassware;
• - chemical reagents.

Instructions

You need to have a good understanding of how the properties of chemical elements change depending on their location in the D.I. table. Mendeleev. Therefore, repeat the periodic law, the electronic structure of atoms (the oxidation state of elements depends on it), etc.

Without any hands-on work, you can establish the nature of the oxide using only the periodic system. After all, it is known that in periods, in the direction from left to right, the alkaline properties of oxides change to amphoteric, and then to acidic. For example, in the III period, sodium oxide (Na2O) exhibits basic properties, the compound of aluminum with oxygen (Al2O3) is amphoteric in nature, and chlorine oxide (ClO2) is acidic.

Keep in mind that in the main subgroups the alkaline properties of the oxides increase from top to bottom, and the acidity, on the contrary, weakens. Thus, in group I, cesium oxide (CsO) has a stronger basicity than lithium oxide (LiO). In group V, nitrogen oxide (III) is acidic, and bismuth oxide (Bi2O5) is already basic.

Another way to determine the nature of the oxides. Let's say the task is given to experimentally prove the basic, amphoteric and acidic properties of calcium oxide (CaO), 5-valent phosphorus oxide (P2O5(V)) and zinc oxide (ZnO).

First, take two clean test tubes. From the bottles, using a chemical spatula, pour a little CaO into one and P2O5 into the other. Then pour 5-10 ml of distilled water into both reagents. Stir with a glass rod until the powder is completely dissolved. Dip pieces of litmus paper into both test tubes. Where calcium oxide is located, the indicator will turn blue, which is proof of the basic nature of the compound being tested. In a test tube with phosphorus (V) oxide, the paper will turn red, therefore P2O5 is an acidic oxide.

Since zinc oxide is insoluble in water, react with an acid and a hydroxide to prove that it is amphoteric. In both cases, ZnO crystals will enter into a chemical reaction. For example:
ZnO + 2KOH = K2ZnO2 + H2O
3ZnO + 2H3PO4-> Zn3(PO4)2? + 3H2O

Please note

Remember, the nature of the properties of the oxide directly depends on the valency of the element included in its composition.

Useful advice

Do not forget that there are also so-called indifferent (non-salt-forming) oxides that do not react under normal conditions with either hydroxides or acids. These include non-metal oxides with valence I and II, for example: SiO, CO, NO, N2O, etc., but there are also “metallic” ones: MnO2 and some others.