In the ground state it has three unpaired electrons. Unpaired electron

Paired electrons

If there is one electron in an orbital, it is called unpaired, and if there are two, then this paired electrons.

Four quantum numbers n, l, m, m s completely characterize the energy state of an electron in an atom.

When considering the structure of the electron shell of multielectron atoms of various elements, it is necessary to take into account three main provisions:

· Pauli principle,

· principle of least energy,

Hund's rule.

According to Pauli principle An atom cannot have two electrons with the same values of all four quantum numbers.

The Pauli principle determines the maximum number of electrons in one orbital, level and sublevel. Since AO is characterized by three quantum numbers n, l, m, then the electrons of a given orbital can differ only in the spin quantum number m s. But the spin quantum number m s can only have two values + 1/2 and – 1/2. Consequently, one orbital can contain no more than two electrons with different values of spin quantum numbers.

Rice. 4.6. The maximum capacity of one orbital is 2 electrons.

The maximum number of electrons at an energy level is defined as 2 n 2 , and at the sublevel – like 2(2 l+ 1). The maximum number of electrons located at different levels and sublevels is given in Table. 4.1.

Table 4.1.

Maximum number of electrons at quantum levels and sublevels

Energy level	Energy sublevel	Possible values of the magnetic quantum number m	Number of orbitals per	Maximum number of electrons per
sublevel	level	sublevel	level
K (n=1)	s (l=0)
L (n=2)	s (l=0) p (l=1)	–1, 0, 1
M (n=3)	s (l=0) p (l=1) d (l=2)	–1, 0, 1 –2, –1, 0, 1, 2
N (n=4)	s (l=0) p (l=1) d (l=2) f (l=3)	–1, 0, 1 –2, –1, 0, 1, 2 –3, –2, –1, 0, 1, 2, 3

The sequence of filling orbitals with electrons is carried out in accordance with principle of least energy .

According to the principle of least energy, electrons fill orbitals in order of increasing energy.

The order of filling the orbitals is determined Klechkovsky's rule: the increase in energy and, accordingly, the filling of orbitals occurs in increasing order of the sum of the principal and orbital quantum numbers (n + l), and if the sum is equal (n + l) - in increasing order of the principal quantum number n.

For example, the energy of an electron at the 4s sublevel is less than at the 3 sublevel d, since in the first case the amount n+ l = 4 + 0 = 4 (recall that for s-sublevel value of orbital quantum number l= = 0), and in the second n+ l = 3 + 2= 5 ( d- sublevel, l= 2). Therefore, sublevel 4 is filled first s, and then 3 d(see Fig. 4.8).

On 3 sublevels d (n = 3, l = 2) , 4R (n = 4, l= 1) and 5 s (n = 5, l= 0) sum of values P And l are identical and equal to 5. In case of equal values of the sums n And l the sublevel with the minimum value is filled first n, i.e. sublevel 3 d.

In accordance with the Klechkovsky rule, the energy of atomic orbitals increases in the series:

1s < 2s < 2R < 3s < 3R < 4s < 3d < 4R < 5s < 4d < 5p < 6s < 5d »

"4 f < 6p < 7s….

Depending on which sublevel in the atom is filled last, all chemical elements are divided into 4 electronic family : s-, p-, d-, f-elements.

4 4d

3 4s

1 2s

Levels Sublevels

Rice. 4.8. Energy of atomic orbitals.

Elements whose atoms are the last to fill the s-sublevel of the outer level are called s-elements . U s-valence elements are the s-electrons of the outer energy level.

U p-elements The p-sublayer of the outer layer is filled last. Their valence electrons are located on p- And s-sub-levels of the external level. U d-elements are filled in last d-sublevel of the preexternal level and valence are s-electrons of the external and d-electrons of the pre-external energy levels.

U f-elements last to be filled f-sublevel of the third outer energy level.

The order of electron placement within one sublevel is determined Hund's rule:

within a sublevel, electrons are placed in such a way that the sum of their spin quantum numbers has a maximum absolute value.

In other words, the orbitals of a given sublevel are filled first by one electron with the same value of the spin quantum number, and then by a second electron with the opposite value.

For example, if it is necessary to distribute 3 electrons in three quantum cells, then each of them will be located in a separate cell, i.e. occupy a separate orbital:

∑m s= ½ – ½ + ½ = ½.

The order of electron distribution among energy levels and sublevels in the shell of an atom is called its electronic configuration, or electronic formula. Composing electronic configuration number energy level (main quantum number) is designated by numbers 1, 2, 3, 4..., sublevel (orbital quantum number) – by letters s, p, d, f. The number of electrons in a sublevel is indicated by a number, which is written at the top of the sublevel symbol.

The electronic configuration of an atom can be depicted as the so-called electron graphic formula. This is a diagram of the arrangement of electrons in quantum cells, which are a graphical representation of an atomic orbital. Each quantum cell can contain no more than two electrons with different spin quantum numbers.

To create an electronic or electronic-graphic formula for any element, you should know:

1. Serial number of the element, i.e. the charge of its nucleus and the corresponding number of electrons in the atom.

2. The period number, which determines the number of energy levels of the atom.

3. Quantum numbers and the connection between them.

For example, a hydrogen atom with atomic number 1 has 1 electron. Hydrogen is an element of the first period, so the only electron occupies the one located in the first energy level s-orbital having the lowest energy. The electronic formula of the hydrogen atom will be:

1 N 1 s 1 .

The electronic graphic formula of hydrogen will look like:

Electronic and electron-graphic formulas of the helium atom:

2 Not 1 s 2

2 Not 1 s

reflect the completeness of the electronic shell, which determines its stability. Helium is a noble gas characterized by high chemical stability (inertness).

The lithium atom 3 Li has 3 electrons, it is an element of period II, which means that the electrons are located at 2 energy levels. Two electrons fill s- sublevel of the first energy level and the 3rd electron is located on s- sublevel of the second energy level:

3 Li 1 s 2 2s 1

Valence I

The lithium atom has an electron located at 2 s-sublevel, is less tightly bound to the nucleus than electrons of the first energy level, therefore, in chemical reactions, a lithium atom can easily give up this electron, turning into the Li + ion ( and he -electrically charged particle ). In this case, the lithium ion acquires a stable complete shell of the noble gas helium:

3 Li + 1 s 2 .

It should be noted that, the number of unpaired (single) electrons determines element valency , i.e. its ability to form chemical bonds with other elements.

Thus, a lithium atom has one unpaired electron, which determines its valency equal to one.

Electronic formula of the beryllium atom:

4 Be 1s 2 2s 2 .

Electron graphic formula of the beryllium atom:

2 Valence mainly

State is 0

Beryllium has sublevel 2 electrons that come off easier than others. s 2, forming the Be +2 ion:

It can be noted that the helium atom and the ions of lithium 3 Li + and beryllium 4 Be +2 have the same electronic structure, i.e. are characterized isoelectronic structure.

For the correct answer to each of tasks 1-8, 12-16, 20, 21, 27-29, 1 point is given.

Tasks 9–11, 17–19, 22–26 are considered completed correctly if the sequence of numbers is indicated correctly. For a complete correct answer in tasks 9–11, 17–19, 22–26, 2 points are given; if one mistake is made - 1 point; for an incorrect answer (more than one error) or lack thereof – 0 points.

Theory on assignment:

1) F 2) S 3) I 4) Na 5) Mg

Determine which atoms of the indicated elements in the ground state are missing one electron before the outer electron layer is completed.

The eight-electron shell corresponds to the shell of an inert gas. For each of the substances in the period in which they are found there corresponds an inert gas, for fluorine neon, for sulfur argon, for iodine xenon, for sodium and magnesium argon, but of the listed elements, only fluorine and iodine lack one electron to reach the eight-electron shell, since they are in the seventh group.

To complete the task, use the following series of chemical elements. The answer in the task is a sequence of three numbers, under which the chemical elements in this row are indicated.

1) Be 2) H 3) N 4) K 5) C

Determine which atoms of the indicated elements in the ground state contain the same number of unpaired electrons.

4 Be Beryllium: 1s 2 2s 2

7 N Nitrogen: 1s 2 2s 2 2p 3

Number of unpaired electrons - 1

6 C Carbon: 1s 2 2s 2 2p 2

1s 2	2s 2	2p 3
↓	↓

Number of unpaired electrons - 2

From this it is obvious that for hydrogen and potassium the number of unpaired electrons is the same.

To complete the task, use the following series of chemical elements. The answer in the task is a sequence of three numbers, under which the chemical elements in this row are indicated.

1) Ge 2) Fe 3) Sn 4) Pb 5) Mn

Determine which atoms of the elements indicated in the series have valence electrons in both the s- and d-sublevels.

To solve this task, it is necessary to describe the upper electronic level of the elements:

32 Ge Germanium: 3d 10 4s 2 4p 2
26 Fe Iron: 3d 6 4s 2
50 Sn Tin: 4d 10 5s 2 5p 2
82 Pb Lead: 4f 14 5d 10 6s 2 6p 2
25 Mn Manganese: 3d 5 4s 2

In iron and manganese, valence electrons are located in the s- and d-sublevels.

To complete the task, use the following series of chemical elements. The answer in the task is a sequence of three numbers, under which the chemical elements in this row are indicated.

1) Br 2) Si 3) Mg 4) C 5) Al

Determine which atoms of the elements indicated in the series in the excited state have the electronic formula of the external energy level ns 1 np 3

For a non-excited state, the electronic formula is ns 1 np 3 will represent ns 2 np 2, it is precisely the elements of this configuration that we need. Let's write down the upper electronic level of the elements (or simply find the elements of the fourth group):

35 Br Bromine: 3d 10 4s 2 4p 5
14 Si Silicon: 3s 2 3p 2
12 Mg Magnesium: 3s 2
6 C Carbon: 1s 2 2s 2 2p 2
13 Al Aluminum: 3s 2 3p 1

For silicon and carbon, the upper energy level coincides with the desired one

To complete the task, use the following series of chemical elements. The answer in the task is a sequence of three numbers, under which the chemical elements in this row are indicated.

1) Si 2) F 3) Al 4) S 5) Li

how to determine the number of unpaired electrons in an atom and got the best answer

Answer from Rafael ahmetov[guru]
Using Klechkovsky's rule, write the electronic formula. This can be easily determined using the electronic formula. For example, the electronic formula of carbon is 1s2 2s2 2p2, we see that there are 2 electrons in the s-orbitals, i.e. they are paired. There are 2 electrons in p-orbitals, but there are three 2-p orbitals. This means that according to Hund’s rule, 2 electrons will occupy 2 different p-orbitals, and carbon has 2 unpaired electrons. Reasoning similarly, we see that the nitrogen atom has 1s2 2s2 2p3 - 3 unpaired electrons. Oxygen has 1s2 2s2 2p4 - there are 4 electrons in p-orbitals. 3 electrons are located one at a time in different p-orbitals, and there is no separate place for the fourth. Therefore, it pairs with one of the three, while two remain unpaired. Similarly, fluorine 1s2 2s2 2p5 has one unpaired electron, and neon 1s2 2s2 2p6 has no unpaired electrons.
In exactly the same way, we need to consider both the d- and f-orbitals (if they are involved in the electronic formula, and do not forget that there are five d-orbitals and seven f-orbitals.

Answer from Vadim Belenetsky[guru]
You don’t have to describe any element and then it will be clear whether there are unpaired electrons or not. For example, aluminum has a charge of +13. and the distribution by levels is 2.8.3. It is already clear that the p-electron in the last layer is unpaired. And check all elements in the same way.

Answer from Eenat Lezgintsev[newbie]
Vadim, can you give us more details?

Answer from Egor Ershov[newbie]
The number of unpaired electrons is equal to the number of the group in which the element is located

Answer from 3 answers[guru]

Hello! Here is a selection of topics with answers to your question: how to determine the number of unpaired electrons in an atom

Indicate the quantum numbers (n, l, m(l), m(s)) of the electron that is the last in the filling order, and determine the number
what is there to think? the last one will be the 5p electron.
n = 5 (principal number = level number)

CHECK PAPER No. 1 Option-1

Exercise 1.

1. The ion has an eight-electron outer shell: 1) P 3+ 2) S 2- 3) C 4+ 4) Fe 2+
2. Number of electrons in the iron ion Fe 2+ equals: 1) 54 2) 28 3) 58 4) 24
3. In the ground state, an atom has three unpaired electrons
1) silicon 2) phosphorus 3) sulfur 4) chlorine
4. Electronic configuration Is 2 2s 2 2p 6 3s 2 3p 6 corresponds to the ion: 1) Cl - 2) N3 - 3) Br - 4) O 2-
5. Ca have the same electronic configuration of the outer level 2+ And
1) K + 2) Ar 3) Ba 4) F -
6. Element to which the highest oxide of composition R corresponds 2 O 7 has an external level electronic configuration: 1) ns 2 np 3 2) ns 2 np 5 3) ns 2 np 1 4) ns 2 np 2

7. An atom has the largest radius: 1) tin 2) silicon 3) lead 4) carbon
8. An atom has the smallest radius: 1) bromine 2) arsenic 3) barium 4) tin
9. In a sulfur atom, the number of electrons in the outer energy level and the charge of the nucleus are equal, respectively 1)4 and + 16 2)6 and + 32 3)6 and + 16 4)4 and + 32
10. Particles have the same electronic structure
1) Na 0 and Na + 2) Na 0 and K 0 3) Na + and F - 4) Cr 2+ and Cr 3+
Task 2.

1. In ammonia and barium chloride, the chemical bond is respectively

1) ionic and covalent polar

2) covalent polar and ionic

3) covalent nonpolar and metallic

4) covalent nonpolar and ionic

2. Substances with only ionic bonds are listed in the following series:

1) F 2, CCl 4, KS1

2) NaBr, Na 2 O, KI

3) SO 2, P 4, CaF 2

4) H 2 S, Br 2, K 2 S

3. In which series do all substances have a polar covalent bond?

1) HCl, NaCl, Cl 2

2) O 2 , H 2 O, CO 2

3) H 2 O, NH 3, CH 4

4. Covalent nonpolar bond is characteristic of

1) C1 2 2) SO3 3) CO 4) SiO 2

5. A substance with a polar covalent bond is

1) C1 2 2) NaBr 3) H 2 S 4) MgCl 2

6. A substance with a covalent nonpolar bond has the formula

1) NH 3 2) Cu 3) H 2 S 4) I 2

7. Substances with non-polar covalent bonds are

1) water and diamond

2) hydrogen and chlorine

3) copper and nitrogen

4) bromine and methane

8. A chemical bond is formed between atoms with the same relative electronegativity

1) ionic

2) covalent polar

3) covalent nonpolar

4) hydrogen

9. A chemical element in the atom of which the electrons are distributed among the layers as follows: 2, 8, 8, 2 forms a chemical bond with hydrogen

1) covalent polar

2) covalent nonpolar

3) ionic

4) metal

10. Three shared electron pairs form a covalent bond in a molecule

2) hydrogen sulfide

3) methane

4) chlorine

11.The compound has a molecular crystal lattice: 1) hydrogen sulfide; 2) sodium chloride; 3) quartz; 4) copper.

12. Hydrogen bonding is not typical for the substance

1) H 2 O 2) CH 4 3) NH 3 4) CH3OH

In substances: methane, fluorine. Determine the type of bond and type of crystal lattice.

Task 3.

1. Select substances that have an atomic crystal lattice.

1.Graphite 3.Diamond

2.Copper sulfate 4.Silicon oxide

2. Select substances that have an ionic crystal lattice:

1. silicon oxide 2. sodium chloride 3. potassium hydroxide 4. aluminum sulfate

3.The atomic crystal lattice is characteristic of:

1. aluminum and graphite 2. sulfur and iodine

3. silicon oxide and sodium chloride 4. diamond and boron

4. Isotopes are:

1. ethane and ethene 2. O 16 and O 17

3. sodium and potassium 4. graphite and nitrogen

5. Substances having a metal crystal lattice, as a rule:

2. fusible and volatile
3. Solid and electrically conductive
4. Thermally conductive and plastic

6.Install

NAME OF SUBSTANCE:	TYPE OF CHEMICAL BOND:
nitric oxide (II);	covalent nonpolar;
B) sodium sulfide;	covalent polar;
	3) metal;
D) diamond
	5) hydrogen

CHECK PAPER No. 1 Option-2

Exercise 1.

1. The ion has a two-electron outer shell: 1) S 6+ 2) S 2- 3) Br 5+ 4) Sn 4+
2. Electronic configuration Is 2 2s 2 2p 6 3s 2 3p 6 corresponds to an ion
1) Sn 2+ 2) S 2- 3) Cr 3+ 4) Fe 2
3. Element with external level electronic configuration... 3s 2 3p 3 forms a hydrogen compound of the composition: 1) EN 4 2) EN 3) EN 3 4) EN 2
2 2s 2 2p 6 corresponds to an ion
1) A 3+ 2) Fe 3+ 3) Zn 2+ 4) Cr 3+
5. Metal atom, the highest oxide of which is Me 2 ABOUT 3 , has the electronic formula for the outer energy level: 1) ns 2 pr 1 2) ns 2 pr 2 3) ns 2 np 3 4) ns 2 np
6. Higher oxide composition R 2 O 7 forms a chemical element in the atom of which the filling of energy levels with electrons corresponds to a series of numbers:
1) 2, 8, 1 2) 2, 8, 7 3) 2, 8, 8, 1 4) 2, 5
7. In the series of chemical elements Na --> Mg --> Al --> Si
1) the number of valence electrons in atoms increases
2) the number of electronic layers in atoms decreases
3) the number of protons in the nuclei of atoms decreases
4) atomic radii increase
8.Electronic configuration 1s 2 2s 2 2p 6 3.s 2 Zr 6 3d 1 has an ion
1) Ca 2+ 2) A 3+ 3) K + 4) Sc 2+
9. The number of valence electrons in manganese is equal to: 1) 1 2) 3 3) 5 4) 7

10. What electronic configuration does the atom of the most active metal have?

Task 2.

1) dimethyl ether

2) methanol

3) ethylene

4) ethyl acetate

2. 1) HI 2) HC1 3) HF 4) NVg

3. A covalent polar bond is characteristic of each of the two substances whose formulas are

1) KI and H 2 O

2) CO 2 and K 2 O

3) H 2 S and Na 2 S

4) CS 2 and PC1 5

1) C 4 H 10, NO 2, NaCl

2) CO, CuO, CH 3 Cl

3) BaS,C 6 H 6, H 2

4) C 6 H 5 NO 2, F 2, CC1 4

5. Each of the substances indicated in the series has a covalent bond:

1) CaO, C 3 H 6, S 8

2) Fe.NaNO 3 , CO

3) N 2, CuCO 3, K 2 S

4) C 6 H 5 N0 2, SO 2, CHC1 3

6. Each of the substances indicated in the series has a covalent bond:

1) C 3 H 4, NO, Na 2 O

2) CO, CH 3 C1, PBr 3

3) P 2 Oz, NaHSO 4, Cu

4) C 6 H 5 NO 2, NaF, CC1 4

7. Substances of molecular structure are characterized

1) high melting point 2) low melting point 3) hardness

4) electrical conductivity.

8. In which series are the formulas of substances with only covalent polar
connection? 1) C1 2, NO 2, HC1 2) HBr,NO,Br 2 3) H 2 S,H 2 O,Se 4) HI,H 2 O,PH 3

9. A substance with an ionic bond is: 1) Ca 2) MgS 3) H 2 S 4) NH 3

10. Each of two substances has an atomic crystal lattice:

2) diamond and silicon

3) chlorine and iodine

11. Compounds with a covalent polar and covalent nonpolar bond are respectively:

1) water and hydrogen sulfide

2)potassium bromide and nitrogen

3) ammonia and hydrogen

4) oxygen and methane

12. A chemical element in the atom of which the electrons are distributed among the layers as follows: 2, 8, 1 forms a chemical bond with hydrogen

13. Make connections diagrams in substances: sodium nitride, oxygen. Determine the type of bond and type of crystal lattice.

Task 3.

2 .At the nodes of different crystal lattices there may be

1. atoms 2. electrons 3. protons 4. ions 5. molecules

3. Allotropy is called:

1. the existence of several stable isotopes for atoms of the same element

2. the ability of atoms of an element to form several complex substances with atoms of another element

3. the existence of several complex substances, the molecules of which have the same composition, but different chemical structures

4. the existence of several simple substances formed by atoms of the same element

1. molecular 2. atomic

3. ionic 4. metal

1. refractory and highly soluble in water

6.Installcorrespondence between the name of a substance and the type of chemical bond in it.

NAME OF SUBSTANCE:	TYPE OF CHEMICAL BOND:
A) ammonium sulfate;	covalent nonpolar;
B) aluminum;	covalent polar;
B) ammonia;	3) metal;
D) graphite.
	5) hydrogen

7. Are the following judgments about the structure and properties of substances in the solid state true?

A. Both ammonium chloride and carbon(II) monoxide have an ionic crystal lattice.

B. Substances with molecular crystal lattices are characterized by high hardness.

Only A is correct; 3) both judgments are correct;

Only B is true; 4) both judgments are incorrect.

CHECK PAPER No. 1 Option-3

Exercise 1.

1. The number of energy layers and the number of electrons in the outer energy layer of arsenic atoms are equal, respectively: 1) 4, 6 2) 2, 5 3) 3, 7 4) 4, 5
2. What electronic configuration does the atom of the most active metal have?
1) 1s 2 2s 2 2p 1 2) 1s 2 2s 2 2p 6 3s 1 3) 1s 2 2s 2 4) 1s 2 2s 2 2p 6 3s 2 3p 1
3. The number of electrons in an atom is determined
1) the number of protons 2) the number of neutrons 3) the number of energy levels 4) the value of the relative atomic mass
4. Atomic nucleus 81 Br contains: 1)81p and 35n 2) 35p and 46n 3)46p and 81n 4) 46p and 35n
5. An ion containing 16 protons and 18 electrons has a charge
1) +4 2) -2 3) +2 4) -4
6. External energy level of an atom of an element forming a higher oxide of composition EO h , has the formula 1) ns 2 np 1 2) ns 2 np 2 3) ns 2 np 3 4) ns 2 np 4
7. Configuration of the outer electron layer of the sulfur atom in an unexcited state
1) 4s 2 2) 3s 2 3р 6 3) 3s 2 3р 4 4) 4s 2 4р 4
8. Electronic configuration Is 2 2s 2 2p 6 3s 2 3p 6 4s 1 the atom has a ground state
1) lithium 2) sodium 3) potassium 4) calcium
9. The number of protons and neutrons contained in the nucleus of an isotope atom 40 K is equal to, respectively: 1) 19 and 40 2) 21 and 19 3) 20 and 40 4) 19 and 21
10. A chemical element, one of the isotopes of which has a mass number of 44 and contains 24 neutrons in the nucleus, is: 1) chromium 2) calcium 3) ruthenium 4) scandium

Task 2.

1. In ammonia and barium chloride, the chemical bond is respectively

2. The polarity of the bond is most pronounced in the molecule: 1) HI 2) HC1 3) HF 4) NVg

3. Substances with only ionic bonds are listed in the series:

1) F 2, CCl 4, KS1

2) NaBr, Na 2 O, KI

3) SO 2, P 4, CaF 2

4) H 2 S, Br 2, K 2 S

4. Each of the substances indicated in the series has covalent bonds:

1) C 4 H 10, NO 2, NaCl

2) CO, CuO, CH 3 Cl

3) BaS,C 6 H 6, H 2

4) C 6 H 5 NO 2, F 2, CC1 4

5. In which series do all substances have a polar covalent bond?

1) HCl, NaCl, Cl 2

2) O 2 , H 2 O, CO 2

3) H 2 O, NH 3, CH 4

6. Covalent nonpolar bond is characteristic of: 1) C1 2 2) SO3 3) CO 4) SiO 2

7. A substance with a polar covalent bond is: 1) C1 2 2) NaBr 3) H 2 S 4) MgCl 2

8. A substance with a covalent nonpolar bond has the formula: 1) NH 3 2) Cu 3) H 2 S 4) I 2

9. Hydrogen bonds form between molecules

1) dimethyl ether

2) methanol

3) ethylene

4) ethyl acetate

10. Each of two substances has a molecular crystal lattice:

1) silicon oxide (IV) and carbon monoxide (IV)

2) ethanol and methane

3) chlorine and iodine

4) potassium chloride and iron (III) fluoride

11. Compounds with a covalent nonpolar and covalent polar bond are respectively:

1) water and hydrogen sulfide

2)potassium bromide and nitrogen

3) ammonia and hydrogen

4) oxygen and methane

12. A chemical element in the atom of which the electrons are distributed among the layers as follows:

2, 8,8,1 forms a chemical bond with hydrogen

1) covalent polar 2) covalent nonpolar 3) ionic 4) metal

13. Make connections diagrams in substances: sodium oxide, oxygen. Determine the type of bond and type of crystal lattice.

Task 3.

1.Crystal lattice of both sulfur (IV) oxide and sulfur (VI) oxide in the solid state:

ionic; 3) molecular;

metal; 4) atomic.

2. Formula of a substance having a molecular crystal lattice in the solid state:

1) Li; 2) NaCl; 3) Si; 4) CH 3 OH.

3. Each of two substances has an ionic crystal lattice, the formulas of which are:

H 2 S and HC1; 3) CO 2 and O 2;

KBr and NH 4 NO 3; 4) N 2 and NH 3.

4. The metal crystal lattice has:

graphite; 3) aluminum;

silicon; 4) iodine.

5.Installcorrespondence between the name of a substance and the type of chemical bond in it.

NAME OF SUBSTANCE:	TYPE OF CHEMICAL BOND:
A) potassium tetrohydroxyalluminate;	covalent nonpolar;
B) aluminum;	covalent polar;
	3) metal;
D) graphite.
	5) hydrogen

6. Are the following judgments about the structure and properties of substances in the solid state true?

A. Both bromine and magnesium are substances of non-molecular structure.

B. Substances with an atomic crystal lattice are characterized by high hardness.

Only A is correct; 3) both judgments are correct;

only true B; 4) both the judgments are incorrect.

7. Substance having a non-molecular structure:

hydrogen sulfide; 3) sulfur oxide (IV);

potassium bromide; 4) rhombic sulfur.

CHECK PAPER No. 1 Option-4

Exercise 1.

1. Substance formed by ionic bond:

1) ammonia; 3) nitrogen;

2) lithium nitride; 4) nitric oxide (IV).

2. Formula of a substance formed by a covalent nonpolar bond:

1) Br 2; 2) KS1; 3) SO 3; 4) Sa.

3. Formula of a substance formed by a polar covalent bond:

1) NaI; 2) SO 2; 3) Al; 4) R 4.

4. Formula of a substance formed by a metal bond:

1) O 3; 2) S 8; 3) C; 4) Sa.

5. A substance between the molecules of whichnot formed hydrogen bond:

ethanol;

acetic acid;

Compounds with a covalent nonpolar and covalent polar bond are, respectively:

1) methane and chloromethane; 3) methane and graphite;

2) nitrogen and ammonia; 4) diamond and graphite.

Compounds with ionic and covalent polar bonds are respectively:

calcium fluoride and barium oxide;
potassium bromide and hydrogen sulfide;
sodium iodide and iodine;
carbon(II) monoxide and sodium sulfide.

Each of the substances is formed by a covalent polar bond, the formulas of which are:

H 2, O 2, S 8; 3) NaCl, CaS, K 2 O;
CO 2, SiCl 4, HBr; 4) HCl, NaCl, PH 3.

Each of two substances is formed by an ionic bond:

hydrogen bromide and carbon monoxide (IV);
barium and cobalt;
magnesium nitride and barium sulfide;
sodium chloride and phosphine.

Hydrogen bonding is characteristic of each of the two substances, the formulas of which are:

CO 2 and H 2 S; 3) H 2 O and C 6 H 6;
C 2 H 6 and HCHO; 4) HF and CH 3 OH.

Chemical bond in the compound of bromine with an element whose outer electron layer has an electronic formula of 4 s 2 4 p 5 :

covalent nonpolar;
covalent polar;
metal.

Chemical bond in a compound of carbon with an element whose outer electron layer has an electronic formula of 3 s 2 3 p 5 :

metal;
covalent nonpolar;
covalent polar.

13. The most pronounced character of the ionic bond is:

in calcium chloride;

in calcium fluoride;

in calcium bromide;

in calcium iodide.

Task 3.

1. In ammonia and barium chloride, the chemical bond is respectively

1) ionic and covalent polar

2) covalent polar and ionic

3) covalent nonpolar and metallic

4) covalent nonpolar and ionic

2. The polarity of the bond is most pronounced in the molecule: 1) HI 2) HC1 3) HF 4) NVg

3. Substances with only ionic bonds are listed in the series:

1) F 2, CCl 4, KS1

2) NaBr, Na 2 O, KI

3) SO 2, P 4, CaF 2

4) H 2 S, Br 2, K 2 S

4. If a substance is highly soluble in water, has a high melting point, and is electrically conductive, then its crystal lattice is:

1. molecular 2. atomic

3. ionic 4. metal

5. Substances that have a molecular crystal lattice, as a rule:

1. refractory and highly soluble in water
2. fusible and volatile 3. Hard and electrically conductive

6.Installcorrespondence between the name of a substance and the type of chemical bond in it.

NAME OF SUBSTANCE:	TYPE OF CHEMICAL BOND:
A) ammonium sulfate;	covalent nonpolar;
B) aluminum;	covalent polar;
B) ammonia;	3) metal;
D) graphite.
	5) hydrogen

7. Are the following judgments about the composition, structure and properties of substances in the solid state correct?

A. Substances that have atomic crystal lattices can be either simple or complex.

B. Substances with an ionic crystal lattice are characterized by low melting points.

Only A is correct; 3) both judgments are correct;
Only B is true; 4) both judgments are incorrect.

The most famous models Young fashion models

Walsh code sequences, their formation

In the ground state it has three unpaired electrons. Unpaired electron

Theory on assignment:

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