In the series of elements, o s se te increases. Chemistry of chalcogens

Chemistry is a must! how do the oxidizing properties change in the series of elements S---Se---Te---Po? explain the answer. and got the best answer

Answer from Pna Aleksandrovna Tkachenko[active]
In the oxygen subgroup, with increasing atomic number, the radius of atoms increases, and the ionization energy, which characterizes the metallic properties of elements, decreases. Therefore, in the 0--S-Se-Te-Po series, the properties of the elements change from non-metallic to metallic. Under normal conditions, oxygen is a typical non-metal (gas), while polonium is a metal similar to lead.
With an increase in the atomic number of the elements, the value of the electronegativity of the elements in the subgroup decreases. The negative oxidation state is becoming less and less characteristic. The oxidative oxidation state becomes less and less characteristic. The oxidizing activity of simple substances in the series 02--S-Se-Te decreases. So, if sulfur is much weaker, selenium directly interacts with hydrogen, then tellurium does not react with it.
In terms of electronegativity, oxygen is second only to fluorine, therefore, in reactions with all other elements, it exhibits exclusively oxidizing properties. Sulfur, selenium and tellurium in their properties. belong to the group of oxidizing-reducing agents. In reactions with strong reducing agents, they exhibit oxidizing properties, and under the action of strong oxidizing agents. they are oxidized, that is, they exhibit reducing properties.
Possible valencies and oxidation states of the elements of the sixth group of the main subgroup in terms of the structure of the atom.
Oxygen, sulfur, selenium, tellurium and polonium make up the main subgroup of group VI. The outer energy level of the atoms of the elements of this subgroup contains 6 electrons each, which have the s2p4 configuration and are distributed over the cells as follows:

Answer from 2 answers[guru]

Hello! Here is a selection of topics with answers to your question: chemistry, it is very necessary! how do the oxidizing properties change in the series of elements S---Se---Te---Po? explain the answer.

in a series of elements O-S-Se with an increase in the ordinal number of a chemical element, electronegativity 1) increases. 2) smart.
O-S-Se - decreases
C-N-O-F - increases
Fluorine is the most electronegative element.

Dmitry Ivanovich Mendeleev discovered the periodic law, according to which the properties of the elements and the elements they form change periodically. This discovery was graphically displayed in the periodic table. The table shows very well and clearly how the properties of the elements change over the period, after which they are repeated in the next period.

To solve task No. 2 of the Unified State Exam in chemistry, we just need to understand and remember which properties of the elements change in which directions and how.

All this is shown in the figure below.

From left to right, electronegativity, non-metallic properties, higher oxidation states, etc. increase. And the metallic properties and radii decrease.

From top to bottom, vice versa: the metallic properties and radii of atoms increase, while the electronegativity decreases. The highest oxidation state, corresponding to the number of electrons in the outer energy level, does not change in this direction.

Let's look at examples.

Example 1 In the series of elements Na→Mg→Al→Si
A) the radii of atoms decrease;
B) the number of protons in the nuclei of atoms decreases;
C) the number of electron layers in atoms increases;
D) the highest degree of oxidation of atoms decreases;

If we look at the periodic table, we will see that all the elements of this series are in the same period and are listed in the order in which they appear in the table from left to right. To answer this kind of question, you just need to know a few patterns of changes in properties in the periodic table. So from left to right along the period, metallic properties decrease, non-metallic ones increase, electronegativity increases, ionization energy increases, and the radius of atoms decreases. From top to bottom, metallic and reducing properties increase in a group, electronegativity decreases, ionization energy decreases, and the radius of atoms increases.

If you were attentive, you already understood that in this case the atomic radii decrease. Answer A.

Example 2 In order of increasing oxidizing properties, the elements are arranged in the following order:
A. F→O→N
B. I→Br→Cl
B. Cl→S→P
D. F→Cl→Br

As you know, in Mendeleev's periodic table, oxidizing properties increase from left to right in a period and from bottom to top in a group. Option B just shows the elements of one group in order from bottom to top. So B fits.

Example 3 The valence of elements in the higher oxide increases in the series:
A. Cl→Br→I
B. Cs→K→Li
B. Cl→S→P
D. Al→C→N

In higher oxides, the elements show their highest oxidation state, which will coincide with the valency. And the highest degree of oxidation grows from left to right in the table. We look: in the first and second versions, we are given elements that are in the same groups, where the highest degree of oxidation and, accordingly, the valence in oxides does not change. Cl → S → P - are located from right to left, that is, on the contrary, their valence in the higher oxide will fall. But in the row Al→C→N, the elements are located from left to right, the valence in the higher oxide increases in them. Answer: G

Example 4 In the series of elements S→Se→Te
A) the acidity of hydrogen compounds increases;
B) the highest degree of oxidation of elements increases;
C) the valence of elements in hydrogen compounds increases;
D) the number of electrons in the outer level decreases;

Immediately look at the location of these elements in the periodic table. Sulfur, selenium and tellurium are in the same group, one subgroup. Listed in order from top to bottom. Look again at the diagram above. From top to bottom in the periodic table, metallic properties increase, radii increase, electronegativity, ionization energy and non-metallic properties decrease, the number of electrons at the outer level does not change. Option D is ruled out immediately. If the number of external electrons does not change, then the valence possibilities and the highest oxidation state also do not change, B and C are excluded.

Option A remains. We check for order. According to the Kossel scheme, the strength of oxygen-free acids increases with a decrease in the oxidation state of an element and an increase in the radius of its ion. The oxidation state of all three elements is the same in hydrogen compounds, but the radius grows from top to bottom, which means that the strength of acids also grows.
The answer is A.

Example 5 In order of weakening of the main properties, the oxides are arranged in the following order:
A. Na 2 O → K 2 O → Rb 2 O
B. Na 2 O → MgO → Al 2 O 3
B. BeO→BaO→CaO
G. SO 3 → P 2 O 5 → SiO 2

The main properties of oxides weaken synchronously with the weakening of the metallic properties of the elements forming them. And Me-properties weaken from left to right or from bottom to top. Na, Mg and Al are just arranged from left to right. Answer B.

Problem 773.
What explains the difference in the properties of the elements of the 2nd period from the properties of their electronic counterparts in subsequent periods?
Solution:
The difference between the properties of the elements of the 2nd period and the properties of their electronic counterparts in subsequent periods is explained
the fact that the atoms of the elements of the 2nd period in the outer electron layer do not contain a d-sublevel. For example, the elements of the main subgroup of group VI: O, S, Se, Te, Po are electronic analogues, since their atoms contain six electrons on the outer electronic layer, two on the s- and four on the p-sublevel. The electronic configuration of their valence layer is: ns2np4. The oxygen atom differs from the atoms of other elements of the subgroup by the absence of a d-sublevel in the outer electron layer:

Such an electronic structure of the oxygen atom does not allow the atom to unpair electrons, therefore covalence oxygen is usually equal to 2 (the number of unpaired valence electrons). Here, an increase in the number of unpaired electrons is possible only by transferring the electron to the next energy level, which, of course, is associated with a large expenditure of energy. Atoms of elements of subsequent periods +16S, +34Se, +52Te and +84Po on the valence electron layer have free d-orbitals:

Such an electronic structure of atoms allows the atoms of these elements to pair electrons, therefore, in an excited state, the number of unpaired electrons increases due to the transfer of s- and p-electrons to free d-orbitals. As a result, these elements are covalence equal not only to 2, but also to 4 and 6:

A) ( covalence – 4)

b) ( covalence – 4)

Therefore, unlike the oxygen atom, the atoms of sulfur, selenium and tellurium can participate in the formation of not only two, but also four or six covalent bonds. Atoms of other periods, which also have unoccupied d-orbitals, behave similarly, can go into an excited state and form an additional number of unpaired electrons.

Diagonal similarity of elements

Problem 774.
What is manifested diagonal element similarity? What reasons cause it? Compare the properties of beryllium, magnesium and aluminum.
Solution:
Diagonal similarity - the similarity between the elements located in the Periodic system of elements diagonally from each other, as well as their corresponding simple substances and compounds. The diagonal from the upper left corner to the lower right corner unites somewhat similar elements. This is due to approximately the same increase in non-metallic properties in periods and metallic properties in groups. Diagonal analogy can manifest itself in two forms: the similarity of the general chemical nature of the elements, which is manifested in all compounds of the same type. Diagonal analogy in a broad sense is due to the proximity of the energy and dimensional characteristics of analog elements. In turn, this is determined by a nonmonotonic change, for example, in the electronegativity and orbital radii of the elements horizontally (in a period) and vertically (in a group). Due to this nonmonotonicity, it turns out that the situation is possible when the difference between the characteristics of elements along the diagonal turns out to be smaller than along the horizontal and vertical lines, which leads to a greater chemical similarity of the diagonally located elements in neighboring groups compared to the group analogy. The moeno similarity can be explained by the close charge/radius ratios of the ion.

diagonal similarity observed in pairs of elements Li and Mg, Be and Al, B and Si, etc. This pattern is due to the tendency to change properties vertically (in groups) and their change horizontally (in periods).

It is associated with an increase in non-metallic properties in periods from left to right and in groups from bottom to top. Therefore, lithium is similar to magnesium, beryllium to aluminum, boron to silicon, carbon to phosphorus. Thus, lithium and magnesium form many alkyl and aryl compounds, which are often used in organic chemistry. Beryllium and aluminum have similar redox potentials. Boron and silicon form volatile, highly reactive molecular hydrides.

The chemical properties of beryllium are in many ways similar to those of magnesium (Mg) and, especially, aluminum (Al). The closeness of the properties of beryllium and aluminum is explained by the almost identical ratio of the cation charge to its radius for the Be 2+ and Al 3+ ions. Ve - exhibits, like aluminum, amphoteric properties.

For beryllium and aluminum, the ratio of ion radius to charge, 1/nm, respectively, is 45.4 and 41.7, much higher than for magnesium - 24.4. Magnesium hydroxide has a medium base, while beryllium and aluminum have amphoteric bases. In magnesium, the crystal lattice of chloride is ionic, while in beryllium and aluminum it is molecular (anhydrous); ionic (crystalline hydrate). Magnesium hydride is an ionic compound, and beryllium and aluminum hydrides are polymers.

Physical and chemical properties of simple substances of elements of the main subgroups

Problem 775.
What are the general patterns of change in the physical and chemical properties of simple substances formed by elements of the main subgroups of the periodic system of elements: a) in a period; b) in a group?
Solution:
a) in a period.
In periods (from left to right) - the nuclear charge increases, the number of electronic levels does not change and is equal to the period number, the number of electrons in the outer layer increases, the radius of the atom decreases, the reducing properties decrease, the oxidizing properties increase, the highest oxidation state increases from +1 to +7 , the lowest oxidation state increases from -4 to +1, the metallic properties of substances weaken, non-metallic properties increase. This is due to an increase in the number of electrons in the last layer. In periods from left to right, for higher oxides and their hydrates, the basic properties decrease, while the acid ones increase.

b) in a group.
In the main subgroups (from top to bottom) - the nuclear charge increases, the number of electronic levels increases, the number of electrons on the outer layer does not change and is equal to the group number, the radius of the atom increases, the reducing properties increase, the oxidizing properties decrease, the highest oxidation state is constant and equal to the number groups, the lowest oxidation state does not change and is equal to (- No. of the group), the metallic properties of substances are enhanced, non-metallic properties are weakened .. The formulas of higher oxides (and their hydrates) are common to the elements of the main and secondary subgroups. In higher oxides and their hydrates of elements of groups I - III (except boron), basic properties predominate, from IV to VIII - acidic. In each main subgroup (except VIII), the basic character of oxides and hydroxides increases from top to bottom, while the acidic properties weaken.

This is due to an increase in the number of electron layers and, consequently, to a decrease in the forces of attraction of the electrons of the last layer to the nucleus.

Acid-base properties of oxides and hydroxides of elements

Problem 776.
How do the acid-base and redox properties of higher oxides and hydroxides of elements change with an increase in the charge of their nuclei: a) within a period; b) within the group?
Solution:
a) Within a period, with an increase in the charge of the nuclei of atoms of elements, the acid-base properties of their higher oxides change as follows, the ability to form acids decreases. The change in acid-base properties over the period can be well seen on the example of the following compounds of elements of the third period:

The redox properties over periods with an increase in the charges of the atoms of the elements change as follows, the reducing properties weaken and the oxidizing properties of the elements increase. For example, in the third period, the reducing ability decreases in the sequence: Na 2 O, MgO, Al 2 O 3, SiO 2, P 2 O 5, and the oxidizing ability increases in the sequence: NaOH, Mg (OH) 2, Al (OH ) 3 , H 3 PO 4 , H 2 SO 4 , HClO 4 . The acid-reducing properties of elements depend on the number of oxidation states they exhibit. According to the period, the number of oxidation states shown by the elements naturally increases: Na shows two degrees of oxidation (0 and +1), Cl - seven (0, -1, +1, +3, +4, +5, +6, +7).

b) In groups, with an increase in the charges of the nuclei of the atoms of the elements, the acid-base properties of the oxides and hydroxides of the elements change as follows, the basic properties increase and the acid ones weaken. For example, in groups of electropositive elements, the base strength increases: Be (OH) 2 is an amphoteric compound, and Ba (OH) 2 is a strong base. In groups, with an increase in the charges of atoms of elements, the reducing ability of higher oxides and hydroxides of elements increases, and the oxidizing ability decreases, for example, in the elements of the VIIth group (HClO 4, HBrO 4, HIO 4), the strongest reducing agent is HClO 4, and the weakest is HIO 4 . In group II (BeO, MgO, CaO, SrO, BaO), the strongest reducing agent is BaO, and the weakest is BeO.

Introduction

The textbook on the chemistry of chalcogens is the second in a series devoted to the chemistry of the elements of the main subgroups of the periodic system of D.I. Mendeleev. It was written on the basis of a course of lectures on inorganic chemistry delivered at Moscow State University over the past 10 years by Academician Yu.D. Tretyakov and Professor V.P. Zlomanov.

In contrast to previously published methodological developments, the manual presents new factual material (catenation, a variety of chalcogen oxoacids (VI), etc.), a modern explanation of the patterns of changes in the structure and properties of chalcogen compounds using the concepts of quantum chemistry, including the molecular orbital method, relativistic effect, etc. The material of the manual was selected for the purpose of illustrative illustration of the relationship between the theoretical course and practical training in inorganic chemistry.

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§ 1. General characteristics of chalcogens (E).

The elements of the VI main subgroup (or the 16th group according to the new IUPAC nomenclature) of the periodic system of elements of D.I. Mendeleev include oxygen (O), sulfur (S), selenium (Se), tellurium (Te) and polonium (Po). The group name of these elements is chalcogens(term "chalcogen" comes from the Greek words "chalkos" - copper and "genos" - born), that is, "giving birth to copper ores", due to the fact that in nature they occur most often in the form of copper compounds (sulfides, oxides, selenides, etc. ).

In the ground state, chalcogen atoms have the electronic configuration ns 2 np 4 with two unpaired p-electrons. They belong to even elements. Some properties of chalcogen atoms are presented in Table 1.

When moving from oxygen to polonium, the size of atoms and their possible coordination numbers increase, while the ionization energy (E ion) and electronegativity (EO) decrease. By electronegativity (EO), oxygen is second only to the fluorine atom, and the sulfur and selenium atoms are also inferior to nitrogen, chlorine, bromine; oxygen, sulfur and selenium are typical non-metals.

In compounds of sulfur, selenium, tellurium with oxygen and halogens, oxidation states +6, +4 and +2 are realized. With most other elements, they form chalcogenides, where they are in the -2 oxidation state.

Table 1. Properties of atoms of elements of group VI.

Properties
atomic number
Number of stable isotopes
Electronic configuration			3d 10 4s 2 4p 4	4d 10 5s 2 5p 4	4f 14 5d 10 6s 2 6p 4
Covalent radius, E
First ionization energy, E ion, kJ/mol
Electronegativity (Pauling)
Affinity of an atom to an electron, kJ/mol

The stability of compounds with the highest oxidation state decreases from tellurium to polonium, for which compounds with oxidation states of 4+ and 2+ are known (for example, PoCl 4 , PoCl 2 , PoO 2). This may be due to an increase in the bond strength of 6s 2 electrons with the nucleus due to relativistic effect. Its essence is to increase the speed of movement and, accordingly, the mass of electrons in elements with a large nuclear charge (Z> 60). The "weighting" of electrons leads to a decrease in the radius and an increase in the binding energy of 6s electrons with the nucleus. This effect is more clearly manifested in compounds of bismuth, an element of group V, and is discussed in more detail in the corresponding manual.

The properties of oxygen, as well as other elements of the 2nd period, differ from the properties of their heavier counterparts. Owing to the high electron density and strong interelectron repulsion, the electron affinity and E-E bond strength of oxygen is less than that of sulfur. Metal-oxygen (M-O) bonds are more ionic than M-S, M-Se, etc. bonds. Due to the smaller radius, the oxygen atom, unlike sulfur, is able to form strong -bonds (p - p) with other atoms - for example, oxygen in the ozone molecule, carbon, nitrogen, phosphorus. When moving from oxygen to sulfur, the strength of a single bond increases due to a decrease in interelectronic repulsion, and the strength of a bond decreases, which is associated with an increase in radius and a decrease in the interaction (overlap) of p-atomic orbitals. Thus, if oxygen is characterized by the formation of multiple (+) bonds, then sulfur and its analogues are characterized by the formation of single chain bonds - E-E-E (see § 2.1).

There are more analogies in the properties of sulfur, selenium and tellurium than with oxygen and polonium. So, in compounds with negative oxidation states, reducing properties increase from sulfur to tellurium, and in compounds with positive oxidation states, oxidizing properties.

Polonium is a radioactive element. The most stable isotope is obtained by bombarding nuclei with neutrons and subsequent -decay:

( 1/2 = 138.4 days).

The decay of polonium is accompanied by the release of a large amount of energy. Therefore, polonium and its compounds decompose solvents and vessels in which they are stored, and the study of Po compounds presents considerable difficulties.

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§ 2. Physical properties of simple substances.
Table 2. Physical properties of simple substances.

		Density	Temperatures, o C		Heat of atomization, kJ/mol	Electrical Resistance (25 ° C), Ohm. cm
			melting
S
Se	hex.
						1.3. 10 5 (liquid, 400 o C)
Those hex.	hex.
Ro

With an increase in the covalent radius in the O-S-Se-Te-Po series, the interatomic interaction and the corresponding temperatures of phase transitions, as well as atomization energy, that is, the energy of the transition of solid simple substances into the state of a monatomic gas, increases. The change in the properties of chalcogens from typical non-metals to metals is associated with a decrease in the ionization energy (Table 1) and structural features. Oxygen and sulfur are typical dielectrics, that is, substances that do not conduct electricity. Selenium and tellurium - semiconductors[substances whose electrophysical properties are intermediate between the properties of metals and non-metals (dielectrics). The electrical conductivity of metals decreases, and that of semiconductors increases with increasing temperature, which is due to the peculiarities of their electronic structure)], and polonium is a metal.

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§ 2.1. Chalcogen catenation. Allotropy and polymorphism.

One of the characteristic properties of chalcogen atoms is their ability to bind to each other in rings or chains. This phenomenon is called catenation. The reason for this is related to the different strengths of single and double bonds. Consider this phenomenon on the example of sulfur (Table 3).

Table 3. Energies of single and double bonds (kJ/mol).

It follows from the given values ​​that the formation of two single -bonds for sulfur instead of one double (+) is associated with a gain in energy (530 - 421 = 109 J / mol). For oxygen, on the contrary, one double bond is energetically preferable (494-292=202 kJ/mol) than two single bonds. The decrease in the strength of the double bond upon the transition from O to S is associated with an increase in the size of the p-orbitals and a decrease in their overlap. Thus, for oxygen, catenation is limited to a small number of unstable compounds: O 3 ozone, O 4 F 2 .

cyclic polycations .

Allotropy and polymorphism of simple substances are associated with catenation. Allotropy is the ability of the same element to exist in different molecular forms. The phenomenon of allotropy is attributed to molecules containing a different number of atoms of the same element, for example, O 2 and O 3, S 2 and S 8, P 2 and P 4, etc. The concept of polymorphism applies only to solids. Polymorphism- the ability of a solid substance with the same composition to have a different spatial structure. Examples of polymorphic modifications are monoclinic sulfur and rhombic sulfur, consisting of the same S 8 cycles, but placed differently in space (see § 2.3). Let us first consider the properties of oxygen and its allotropic form - ozone, and then the polymorphism of sulfur, selenium and tellurium.

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AKHMETOV M. A. LESSON 3. ANSWERS TO TASKS.

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Periodic law and the periodic system of chemical elements. Radii of atoms, their periodic changes in the system of chemical elements. Patterns of changes in the chemical properties of elements and their compounds by periods and groups.

1. Arrange the following chemical elements N, Al, Si, C in order of increasing their atomic radii.

ANSWER:

NAndClocated in the same period. To the right is locatedN. So nitrogen is less than carbon.

C andSilocated in the same group. But C is higher. So C is less thanSi.

SiAndAllocated in one third period, but to the right isSi, MeansSiless thanAl

The order of increasing the size of atoms will be as follows:N, C, Si, Al

2. Which of the chemical elements phosphorus or oxygen exhibits more pronounced non-metallic properties? Why?

ANSWER:

Oxygen exhibits more pronounced non-metallic properties, since it is located above and to the right in the periodic table of elements.

3. How do the properties of group IV hydroxides of the main subgroup change when moving from top to bottom?

ANSWER:

The properties of hydroxides change from acidic to basic. SoH2 CO3 - carbonic acid, as its name implies, exhibits acidic properties, andPb(Oh)2 is the base.

ANSWERS TO TESTS

A1. The strength of oxygen-free acids of non-metals of group VIIA, according to the increase in the charge of the nucleus of atoms of elements

	increases
	decreases
	does not change
	changes periodically

ANSWER: 1

It's about acids.HF, HCl, HBr, HI. In a rowF, Cl, Br, Ian increase in the size of the atoms. Therefore, the internuclear distance increasesH– F, H– Cl, H– Br, H– I. And if so, it means that the bond energy is weakening. And the proton is more easily split off in aqueous solutions

A2. The element has the same valence value in the hydrogen compound and the higher oxide

	germanium

ANSWER: 2

Of course, we are talking about an element of the 4th group (see period. c-th elements)

A3. In which order are simple substances arranged in order of increasing metallic properties?

ANSWER: 1

The metallic properties in a group of elements are known to increase from top to bottom.

A4. In the series Na ® Mg ® Al ®Si

	the number of energy levels in atoms increases
	the metallic properties of the elements are enhanced
	the highest oxidation state of elements decreases
	weaken the metallic properties of the elements

ANSWER: 4

In the period from left to right, non-metallic properties are enhanced, and metallic properties are weakened.

A5. For elements of the carbon subgroup, with increasing atomic number, the

ANSWER: 4.

Electronegativity is the ability to move electrons towards itself when a chemical bond is formed. Electronegativity is almost directly related to non-metallic properties. The non-metallic properties decrease, and the electronegativity also decreases.

A6. In the series of elements: nitrogen - oxygen - fluorine

increases

ANSWER: 3

The number of outer electrons is equal to the group number

A7. Among the chemical elements:

boron - carbon - nitrogen

increases

ANSWER:2

The number of electrons in the outer layer is equal to the highest oxidation state except for (F, O)

A8. Which element has more pronounced non-metallic properties than silicon?

ANSWER: 1

Carbon is in the same group as silicon, only higher.

A9. The chemical elements are arranged in ascending order of their atomic radius in the following order:

ANSWER: 2

In groups of chemical elements, the atomic radius increases from top to bottom.

A10. The metallic properties of the atom are most pronounced:

1) lithium 2) sodium

3) potassium 4) calcium

ANSWER: 3

Among these elements, potassium is located below and to the left.

A11. The most pronounced acidic properties:

Answer: 4 (see answer to A1)

A12. Acid properties of oxides in the series SiO2 ® P2O5 ®SO3

1) weaken

2) intensify

3) do not change

4) change periodically

ANSWER: 2

The acidic properties of oxides, as well as non-metallic properties, increase in periods from left to right

A13. With an increase in the charge of the nucleus of atoms, the acidic properties of oxides in the series

N2O5 ® P2O5 ®As2O5 ® Sb2O5

1) weaken

2) intensify

3) do not change

4) change periodically

ANSWER: 1

In groups from top to bottom, acidic properties, like non-metallic ones, weaken

A14. Acidic Properties of Hydrogen Compounds of Group VIA Elements with Increasing Ordinal Number

1) amplify

2) weaken

3) remain unchanged

4) change periodically

ANSWER: 3

The acidic properties of hydrogen compounds are related to the binding energyH- El. This energy from top to bottom weakens, which means that the acidic properties are enhanced.

A15. The ability to donate electrons in the series Na ® K ® Rb ®Cs

1) is weakening

2) amplifies

3) does not change

4) changes periodically

ANSWER: 2

In this series, the number of electron layers and the distance of electrons from the nucleus increase, therefore, the ability to donate an external electron increases.

A16. In the series Al ®Si ®P ®S

1) the number of electron layers in atoms increases

2) non-metallic properties are enhanced

3) the number of protons in the nuclei of atoms decreases

4) the radii of atoms increase

ANSWER: 2

In the period with an increase in the charge of the nucleus, non-metallic properties are enhanced

A17. In the main subgroups of the periodic system, the reducing ability of atoms of chemical elements increases c

ANSWER: 1

With an increase in the number of electronic levels, the remoteness and screening of the outer electrons from the nucleus increases. Consequently, the ability to return them increases (restorative properties)

A18. According to modern ideas, the properties of chemical elements are periodically dependent on

ANSWER: 3

A19. Atoms of chemical elements that have the same number of valence electrons are located

	diagonally
	in one group
	in one subgroup
	in one period

ANSWER: 2

A20. The element with serial number 114 must have properties similar to

ANSWER: 3. This element will be located in the cell corresponding to the one occupied by lead inVIgroup

A21. In periods, the reducing properties of chemical elements from right to left

	increase
	decrease
	do not change
	change periodically

ANSWER: 1

The nuclear charge decreases.

A22. Electronegativity and ionization energy in the О–S–Se–Te series, respectively

	increases, increases
	increases, decreases
	decreases, decreases
	decreasing, increasing

ANSWER: 3

The electronegativity decreases as the number of filled electron layers increases. Ionization energy is the energy required to remove an electron from an atom. She also shrinks

A23. In which order are the signs of chemical elements arranged in order of increasing atomic radii?