Chemical bond. Determine the type of chemical bond: HCL, Na2S, NH3, I2, MnO2 Hcl bond
Task number 1
From the proposed list, select two compounds in which an ionic chemical bond is present.
- 1. Ca (ClO 2) 2
- 2. HClO 3
- 3. NH 4 Cl
- 4. HClO 4
- 5. Cl 2 O 7
Answer: 13
In the overwhelming majority of cases, it is possible to determine the presence of an ionic type of bond in a compound by the fact that atoms of a typical metal and atoms of a non-metal are simultaneously included in its structural units.
On this basis, we establish that there is an ionic bond in the compound under number 1 - Ca (ClO 2) 2, since in its formula you can see the atoms of a typical metal calcium and atoms of non-metals - oxygen and chlorine.
However, there are no more compounds containing both metal and non-metal atoms in this list.
Among the compounds specified in the task there is ammonium chloride, in which the ionic bond is realized between the ammonium cation NH 4 + and the chloride ion Cl -.
Task number 2
From the list provided, select two compounds in which the type of chemical bond is the same as in the fluorine molecule.
1) oxygen
2) nitric oxide (II)
3) hydrogen bromide
4) sodium iodide
Write down the numbers of the selected connections in the answer field.
Answer: 15
A fluorine molecule (F 2) consists of two atoms of one chemical element of a non-metal, therefore the chemical bond in this molecule is covalent non-polar.
A covalent non-polar bond can be realized only between atoms of the same chemical element of a non-metal.
Of the proposed options, only oxygen and diamond have a covalent non-polar bond. The oxygen molecule is diatomic, it consists of atoms of one chemical element of a non-metal. Diamond has an atomic structure and in its structure, each carbon atom, which is a non-metal, is bonded to 4 other carbon atoms.
Nitric oxide (II) is a substance consisting of molecules formed by atoms of two different non-metals. Since the electronegativities of different atoms are always different, the total electron pair in a molecule is shifted towards a more electronegative element, in this case oxygen. Thus, the bond in the NO molecule is covalent polar.
Hydrogen bromide also consists of diatomic molecules composed of hydrogen and bromine atoms. The common electron pair forming the H-Br bond is shifted towards the more electronegative bromine atom. Chemical bond in the HBr molecule is also covalent polar.
Sodium iodide is an ionic substance formed by a metal cation and an iodide anion. The bond in the NaI molecule is formed due to the transition of an electron from 3 s-orbital of the sodium atom (the sodium atom turns into a cation) to the underfilled 5 p-orbital of the iodine atom (the iodine atom turns into an anion). This chemical bond is called ionic.
Task number 3
From the proposed list, select two substances between the molecules of which hydrogen bonds are formed.
- 1.C 2 H 6
- 2.C 2 H 5 OH
- 3. H 2 O
- 4. CH 3 OCH 3
- 5.CH 3 COCH 3
Write down the numbers of the selected connections in the answer field.
Answer: 23
Explanation:
Hydrogen bonds take place in substances of molecular structure in which covalent communication H-O, H-N, H-F. Those. covalent bonds of a hydrogen atom with atoms of three chemical elements with the highest electronegativity.
Thus, obviously, there are hydrogen bonds between molecules:
2) alcohols
3) phenols
4) carboxylic acids
5) ammonia
6) primary and secondary amines
7) hydrofluoric acid
Task number 4
Select two compounds with ionic chemical bonds from the list.
- 1.PCl 3
- 2.CO 2
- 3. NaCl
- 4.H 2 S
- 5. MgO
Write down the numbers of the selected connections in the answer field.
Answer: 35
Explanation:
In the overwhelming majority of cases, it is possible to draw a conclusion about the presence of an ionic type of bond in a compound by the fact that the structural units of a substance simultaneously include atoms of a typical metal and atoms of a non-metal.
On this basis, we establish that there is an ionic bond in the compound numbered 3 (NaCl) and 5 (MgO).
Note*
In addition to the above sign, the presence of an ionic bond in a compound can be said if its structural unit contains an ammonium cation (NH 4 +) or its organic analogs - alkylammonium cations RNH 3 +, dialkylammonium R 2 NH 2 +, trialkylammonium R 3 NH + or tetraalkylammonium R 4 N +, where R is some hydrocarbon radical. For example, the ionic type of bond occurs in the compound (CH 3) 4 NCl between the cation (CH 3) 4 + and the chloride ion Cl -.
Task number 5
From the proposed list, select two substances with the same type of structure.
4) table salt
Write down the numbers of the selected connections in the answer field.
Answer: 23
Task number 8
Select two substances of non-molecular structure from the proposed list.
2) oxygen
3) white phosphorus
5) silicon
Write down the numbers of the selected connections in the answer field.
Answer: 45
Task number 11
From the proposed list, select two substances in the molecules of which there is a double bond between carbon and oxygen atoms.
3) formaldehyde
4) acetic acid
5) glycerin
Write down the numbers of the selected connections in the answer field.
Answer: 34
Task number 14
From the proposed list, select two substances with an ionic bond.
1) oxygen
3) carbon monoxide (IV)
4) sodium chloride
5) calcium oxide
Write down the numbers of the selected connections in the answer field.
Answer: 45
Task number 15
From the list provided, select two substances with the same type of crystal lattice as diamond.
1) silica SiO 2
2) sodium oxide Na 2 O
3) carbon monoxide CO
4) white phosphorus P 4
5) silicon Si
Write down the numbers of the selected connections in the answer field.
Answer: 15
Task number 20
From the proposed list, select two substances in the molecules of which there is one triple bond.
- 1. HCOOH
- 2. HCOH
- 3.C 2 H 4
- 4.N 2
- 5.C 2 H 2
Write down the numbers of the selected connections in the answer field.
Answer: 45
Explanation:
In order to find the correct answer, let's draw the structural formulas of the compounds from the presented list:
Thus, we see that there is a triple bond in the nitrogen and acetylene molecules. Those. correct answers 45
Task number 21
From the proposed list, select two substances in the molecules of which there is a covalent non-polar bond.
1.Alkaline earth metals are5) to s– elements
6) to p - elements
7) to d - elements
8) to f - elements
2. How many electrons do the atoms of alkaline earth metals contain at the external energy level?
1) One 2) two 3) three 4) four
3. In chemical reactions aluminum atoms exhibit
3) Oxidizing properties 2) acidic properties
4) 3) reducing properties 4) basic properties
4. The interaction of calcium with chlorine refers to reactions
1) Decompositions 2) compounds 3) substitutions 4) exchange
5. The molecular weight of sodium bicarbonate is:
1) 84 2) 87 3) 85 4) 86
3. Which atom is heavier - iron or silicon - and how many times?4. Determine the relative molecular weights of simple substances: hydrogen, oxygen, chlorine, copper, diamond (carbon). Remember which of them are made up of diatomic molecules and which are made up of atoms.
5.Calculate the relative molecular weights of the following compounds of carbon dioxide CO2 sulfuric acid H2SO4 sugar C12H22O11 ethyl alcohol C2H6O marble CaCPO3
6. In hydrogen peroxide, there is one hydrogen atom for one oxygen atom. Determine the formula for hydrogen peroxide, if it is known that its relative molecular weight is 34. What is the mass ratio of hydrogen and oxygen in this compound?
7. How many times is a carbon dioxide molecule heavier than an oxygen molecule?
Help pozhzhzhzhzhaluysta, grade 8 assignment.
"Chemical bond" - the energy of destruction of the lattice into ions _Ekul = Ures. The main provisions of the MO method. Overlapping types of atomic AOs. bonding and antibonding MOs with a combination of atomic orbitals s and s pz and pz px and px. H? C? C? H. ? - Coefficient of repulsion. Qeff =. Ao. Basic theories of chemical bonding.
"Types of chemical bonds" - Substances with ionic bonds, form an ionic crystal lattice. Atoms. Electronegativity. MOU Lyceum No. 18, chemistry teacher L.A. Kalinina Jonah. For example: Na1 + and Cl1-, Li1 + and F1- Na1 + + Cl1- = Na (: Cl :). If e - attach - the ion is charged negatively. The atomic framework is highly durable.
"Life of Mendeleev" - July 18, DI Mendeleev graduated from the Tobolsk gymnasium. August 9, 1850 - June 20, 1855 time of study at the Main Pedagogical Institute... “If you don’t know the names, the knowledge of things will also die” K. Liney. The life and work of D.I. Mendeleev. Ivan Pavlovich Mendeleev (1783 - 1847), the father of a scientist. Opening periodic law.
"Types of chemical bonds" - H3N. Al2O3. The structure of matter ". H2S. MgO. H2. Cu. Mg S. CS2. I. Write down the formulas of substances: 1.with K.N.S. 2.with K.P.S. 3.with I.S. K.N.S. NaF. C. K.P.S. Determine the type of chemical bond. Which of the molecules corresponds to the scheme: A A?
"Mendeleev" - Dobereiner's Triads of Elements. Gases. Work. Life and scientific feat. Periodic table of elements (long form). Newlands' Law of Octaves. Scientific activity... Solutions. A new stage in life. The second version of Mendeleev's system of elements. Part of the table of elements L. Meyer. Discovery of the Periodic Law (1869).
"The life and work of Mendeleev" - Ivan Pavlovich Mendeleev (1783 - 1847), the scientist's father. 1834, January 27 (February 6) - D.I. Mendeleev was born in the city of Tobolsk, in Siberia. 1907, January 20 (February 2) D.I. Mendeleev died of heart paralysis. DI. Meneleev (South Kazakhstan region, Shymkent city). Industry. On July 18, 1849 D.I. Mendeleev graduated from the Tobolsk gymnasium.
There is no unified theory of chemical bonding, conditionally a chemical bond is divided into covalent (universal type of bond), ionic (a special case of a covalent bond), metallic and hydrogen.
Covalent bond
The formation of a covalent bond is possible by three mechanisms: exchange, donor-acceptor and dative (Lewis).
According to exchange mechanism the formation of a covalent bond occurs due to the socialization of common electronic pairs. In this case, each atom seeks to acquire a shell of an inert gas, i.e. get a completed external energy level. The formation of a chemical bond according to the exchange type is depicted using the Lewis formulas, in which each valence electron of an atom is represented by dots (Fig. 1).
Rice. 1 Formation of a covalent bond in the HCl molecule by the exchange mechanism
With the development of the theory of atomic structure and quantum mechanics, the formation of a covalent bond is presented as an overlap of electron orbitals (Fig. 2).
Rice. 2. Formation of a covalent bond due to the overlapping of electron clouds
The greater the overlap of atomic orbitals, the stronger the bond, the shorter the bond length and the greater its energy. A covalent bond can be formed by overlapping different orbitals. As a result of the overlap of s-s, s-p orbitals, as well as d-d, p-p, d-p orbitals by the lateral blades, the formation of bonds occurs. A bond is formed perpendicular to the line connecting the nuclei of 2 atoms. One - and one - bond can form a multiple (double) covalent bond, characteristic of organic substances of the class of alkenes, alkadienes, etc. One - and two - bonds form a multiple (triple) covalent bond, characteristic of organic substances of the class of alkynes (acetylenes).
Formation of a covalent bond along donor-acceptor mechanism consider the example of the ammonium cation:
NH 3 + H + = NH 4 +
7 N 1s 2 2s 2 2p 3
The nitrogen atom has a free lone pair of electrons (electrons are not involved in the formation of chemical bonds inside the molecule), and the hydrogen cation has a free orbital, therefore they are an electron donor and acceptor, respectively.
Let us consider the dative mechanism of the formation of a covalent bond using a chlorine molecule as an example.
17 Cl 1s 2 2s 2 2p 6 3s 2 3p 5
The chlorine atom has both a free lone pair of electrons and vacant orbitals, therefore, it can exhibit the properties of both a donor and an acceptor. Therefore, when a chlorine molecule is formed, one chlorine atom acts as a donor, and the other as an acceptor.
The main characteristics of the covalent bond are: saturation (saturated bonds are formed when an atom attaches to itself as many electrons as its valence capabilities allow; unsaturated bonds are formed when the number of attached electrons is less than the valence capabilities of the atom); directionality (this value is associated with the geometry of the molecule and the concept of "bond angle" - the angle between bonds).
Ionic bond
There are no compounds with a pure ionic bond, although this is understood chemically bound state atoms, in which a stable electronic environment of the atom is created with a complete transition of the total electron density to an atom of a more electronegative element. Ionic bond is possible only between the atoms of electronegative and electropositive elements in the state of oppositely charged ions - cations and anions.
DEFINITION
Ion are called electrically charged particles formed by the detachment or attachment of an electron to an atom.
When an electron is transferred, the atoms of metals and non-metals tend to form a stable configuration of the electron shell around their nucleus. The non-metal atom creates around its core a shell of the next inert gas, and the metal atom - the previous inert gas (Fig. 3).
Rice. 3. Formation of an ionic bond by the example of a sodium chloride molecule
Molecules in which an ionic bond exists in its pure form are found in the vapor state of a substance. The ionic bond is very strong; therefore, substances with this bond have a high melting point. In contrast to the covalent bond, the directionality and saturation are not characteristic of the ionic bond, since electric field created by ions acts equally on all ions due to spherical symmetry.
Metallic bond
The metallic bond is realized only in metals - this is an interaction that holds metal atoms in a single lattice. Only the valence electrons of the metal atoms, belonging to its entire volume, participate in the formation of a bond. In metals, electrons are constantly torn away from atoms, which move throughout the entire mass of the metal. Metal atoms, deprived of electrons, turn into positively charged ions, which tend to receive moving electrons. This continuous process forms the so-called "electron gas" inside the metal, which firmly binds together all the atoms of the metal (Fig. 4).
The metal bond is strong, therefore, metals are characterized by a high melting point, and the presence of "electron gas" gives the metals ductility and ductility.
Hydrogen bond
Hydrogen bond is a specific intermolecular interaction, because its appearance and strength depend on the chemical nature of the substance. It forms between molecules in which a hydrogen atom is bonded to a highly electronegative atom (O, N, S). The appearance of a hydrogen bond depends on two reasons, firstly, the hydrogen atom associated with an electronegative atom does not have electrons and can easily be incorporated into the electron clouds of other atoms, and, secondly, having a valence s-orbital, a hydrogen atom is able to accept a lone pair electrons of an electronegative atom and form a bond with it by the donor-acceptor mechanism.
Chemical bond.
Exercises.
1. Determine the type of chemical bond in the following substances:
Substance | Phosphorus chloride | Sulphuric acid | |||
Communication type | |||||
Substance | Barium oxide | ||||
Communication type |
2. Underline substances in which BETWEEN molecules exists hydrogen bond:
sulphur dioxide; ice; ozone; ethanol; ethylene; acetic acid; hydrogen fluoride.
3. How do they affect bond length, strength and polarity- the radii of the atoms, their electronegativity, the multiplicity of the bond?
a) The larger the radii the atoms that formed the bond, the link length _______
b) The greater the multiplicity (single, double or triple) bonds, so it strength ____________________
v) The greater the difference of electronegativities between two atoms, the polarity of the bond ____________
4. Compare length, strength and polarity of bonds in molecules:
a) bond length: HCl ___HBr
b) bond strength PH3_______NH3
c) communication polarity CCl4 ______CH4
d) bond strength: N2 _______O2
e) the length of the bond between carbon atoms in ethylene and in acetylene: __________
f) the polarity of bonds in NH3 _________ H2O
Tests. A4.Chemical connection.
1. The valence of an atom is
1) the number of chemical bonds formed by a given atom in a compound
2) the oxidation state of the atom
3) the number of electrons donated or received
4) the number of electrons missing to obtain the electronic configuration of the nearest inert gas
A. When a chemical bond is formed, energy is always released
B. The energy of a double bond is less than the energy of a single bond.
1) only A is true 2) only B is true 3) both statements are true 4) both statements are false
3.In substances formed by combining the same atoms, chemical bond
1) ionic 2) covalent polar 3) hydrogen 4) covalent non-polar
4. Compounds with a covalent polar and covalent non-polar bond are, respectively
1) water and hydrogen sulfide 2) potassium bromide and nitrogen
5. Due to the common electron pair, a chemical bond is formed in the compound
1) KI 2) HBr 3) Li2O 4) NaBr
6.Choose a pair of substances, all bonds in which are covalent:
1) NaСl, НСl 2) СО2, ВаО 3) СН3Сl, СН3Nа 4) SO2, NO2
7. A substance with a covalent polar bond has the formula
1) KCl 2) HBr 3) P4 4) CaCl2
8. Compound with ionic nature of the chemical bond
1) phosphorus chloride 2) potassium bromide 3) nitric oxide (II) 4) barium
9. In ammonia and barium chloride, the chemical bond, respectively
1) ionic and covalent polar 2) covalent non-polar and ionic 3) covalent polar and ionic 4) covalent non-polar and metallic
10. Substances with a covalent polar bond are
1) sulfur (IV) oxide 2) oxygen 3) calcium hydride 4) diamond
11. In which row are substances with only a covalent polar bond listed:
1) СН4 Н2 Сl2 2) NH3 HBr CO2 3) PCl3 KCl CCl4 4) H2S SO2 LiF
12. In which row are the substances listed only with ionic type communication:
1) F2O LiF SF4 2) PCl3 NaCl CO2 3) KF Li2O BaCl2 4) CaF2 CH4 CCl4
13. A compound with an ionic bond is formed when interacting
1) CH4 and O2 2) NH3 and HCl 3) C2H6 and HNO3 4) SO3 and H2O
14. In what substance are all chemical bonds - covalent non-polar?
1) Diamond 2) Carbon (IV) oxide 3) Gold 4) Methane
15. The relationship formed between elements with serial numbers 15 and 53
1) ionic 2) metal
3) covalent non-polar 4) covalent polar
16. Hydrogen bond formed between molecules
1) ethane 2) benzene 3) hydrogen 4) ethanol
17. In what substance is hydrogen bonds?
1) Hydrogen sulfide 2) Ice 3) Hydrogen bromide 4) Benzene
18. In what substance are ionic and covalent chemical bonds at the same time?
1) Sodium chloride 2) Hydrogen chloride 3) Sodium sulfate 4) Phosphoric acid
19. A more pronounced ionic character has a chemical bond in the molecule
1) lithium bromide 2) copper chloride 3) calcium carbide 4) potassium fluoride
20. Three common electron pairs form a covalent bond in a molecule of 1) nitrogen 2) hydrogen sulfide 3) methane 4) chlorine
21. How many electrons are involved in the formation of chemical bonds in a water molecule? 4) 18
22. Four covalent bonds are contained in a molecule: 1) CO2 2) C2H4 3) P4 4) C3H4
23. The number of bonds in molecules increases in the series
1) CHCl3, CH4 2) CH4, SO3 3) CO2, CH4 4) SO2, NH3
24. In what compound is the covalent bond between atoms formed by donor-acceptor mechanism? 1) KCl 2) CCl4 3) NH4Cl 4) CaCl2
25. Which of the listed molecules requires the least energy consumption for decomposition into atoms? 1) HI 2) H2 3) O2 4) CO
26. Indicate the molecule in which the binding energy is the highest:
1) N≡N 2) H-H 3) O = O 4) H-F
27. Indicate the molecule in which the chemical bond is the strongest:
1) HF 2) HCl 3) HBr 4) HI
28. Indicate a series characterized by an increase in the length of the chemical bond
1) O2, N2, F2, Cl2 2) N2, O2, F2, Cl2 3) F2, N2, O2, Cl2 4) N2, O2, Cl2, F2
29. The length of the E-O bond increases in the series
1) silicon oxide (IV), carbon monoxide (IV)
2) sulfur (IV) oxide, tellurium (IV) oxide
3) strontium oxide, beryllium oxide
4) sulfur oxide (IV), carbon monoxide (IV)
30. In the series СН4 - SiH4 occurs increase
1) bond strength 2) oxidizing properties
3) bond lengths 4) bond polarities
31. In which row are the molecules arranged in the order of increasing bond polarity?
1) НF, НСl, НВr 2) Н2Sе, Н2S, Н2О 3) NH3, РН3, АsН3 4) СO2, СS2, СSе2
32. The most polar covalent bond in the molecule:
1) CH4 2) CF4 3) CCl4 4) CBr4
33. Indicate the row in which the polarity increases:
1) AgF, F2, HF 2) Cl2, HCl, NaCl 3) CuO, CO, O2 4) KBr, NaCl, KF
Covalent chemical bond, its varieties and mechanisms of formation. Covalent bond characteristics (polarity and bond energy). Ionic bond. Metallic bond. Hydrogen bond.
1. In ammonia and barium chloride, the chemical bond, respectively
1) ionic and covalent polar
2) covalent polar and ionic
3) covalent non-polar and metallic
4) covalent non-polar and ionic
2. Substances with only ionic bonds are listed in the series:
1) F2, CCl4, KS1
2) NaBr, Na2O, KI
3. A compound with an ionic bond is formed by interaction
3) C2H6 and HNO3
4. In which row do all substances have a covalent polar bond?
1) HCl, NaCl. Cl2
4) NaBr. HBr. CO
5. In which row are the formulas of substances with only covalent polar
1) C12, NO2, HC1
6. A covalent non-polar bond is characteristic of
1) С12 2) SO3 3) СО 4) SiO2
7. A substance with a covalent polar bond is
1) С12 2) NaBr 3) H2S 4) MgCl2
8. A substance with a covalent bond is
1) CaC12 2) MgS 3) H2S 4) NaBr
9. A substance with a covalent non-polar bond has the formula
1) NH3 2) Cu 3) H2S 4) I2
10. Substances with a non-polar covalent bond are
1) water and diamond
2) hydrogen and chlorine
3) copper and nitrogen
4) bromine and methane
11.A chemical bond is formed between atoms with the same relative electronegativity
2) covalent polar
3) covalent non-polar
4) hydrogen
12. Covalent polar bond is characteristic for
1) KC1 2) HBr 3) P4 4) CaCl2
13. A chemical element in whose atom electrons are distributed over the layers as follows: 2, 8, 8, 2 forms a chemical bond with hydrogen
1) covalent polar
2) covalent non-polar
4) metal
14. In what substance is the longest bond between carbon atoms in a molecule?
1) acetylene 2) ethane 3) ethene 4) benzene
15. Three common electron pairs form a covalent bond in the molecule
2) hydrogen sulfide
16. Hydrogen bonds are formed between molecules
1) dimethyl ether
2) methanol
3) ethylene
4) ethyl acetate
17. The polarity of the bond is most pronounced in the molecule
1) HI 2) HC1 3) HF 4) HBr
18. Substances with a non-polar covalent bond are
1) water and diamond
2) hydrogen and chlorine
3) copper and nitrogen
4) bromine and methane
19. The hydrogen bond is not characteristic of the substance
1) Н2О 2) СН4 3) NH3 4) СНзОН
20. The covalent polar bond is characteristic for each of the two substances, the formulas of which
2) CO2 and K2O
4) CS2 and PC15
21. The least strong chemical bond in a molecule
1) fluorine 2) chlorine 3) bromine 4) iodine
22. In what substance is the longest chemical bond in the molecule?
1) fluorine 2) chlorine 3) bromine 4) iodine
23. Each of the substances indicated in the series has covalent bonds:
1) C4H10, NO2, NaCl
2) CO, CuO, CH3Cl
4) C6H5NO2, F2, CC14
24. Each of the substances indicated in the series has a covalent bond:
1) CaO, C3H6, S8
2) Fe. NaNO3, CO
3) N2, CuCO3, K2S
4) C6H5N02, SO2, CHC13
25. Each of the substances indicated in the series has a covalent bond:
1) С3Н4, NO, Na2O
2) CO, CH3C1, PBr3
3) P2Oz, NaHSO4, Cu
4) C6H5NO2, NaF, CC14
26. Each of the substances indicated in the series has covalent bonds:
1) C3Ha, NO2, NaF
2) KC1, CH3Cl, C6H12O6
3) P2O5, NaHSO4, Ba
4) C2H5NH2, P4, CH3OH
27. Bond polarity is most pronounced in molecules
1) hydrogen sulfide
3) phosphine
4) hydrogen chloride
28. In a molecule of which substance are the strongest chemical bonds?
29. Among the substances NH4Cl, CsCl, NaNO3, PH3, HNO3 - the number of compounds with an ionic bond is
30. Among the substances (NH4) 2SO4, Na2SO4, CaI2, I2, CO2 - the number of compounds with a covalent bond is
Answers: 1-2, 2-2, 3-4, 4-3, 5-4, 6-1, 7-3, 8-3, 9-4, 10-2, 11-3, 12-2, 13-3, 14-2, 15-1, 16-2, 17-3, 18-2, 19-2, 20-4, 21-4, 22-4, 23-4, 24-4, 25- 2, 26-4, 27-4, 28-1, 29-3, 30-4