The position of non-metals in the periodic table of a singularity. Non-metals

All currently known chemical elements have a common "house" - a periodic system. However, they are located there not as necessary, but in a strict order, of a certain sequence. One of the main criteria by which all atoms are classified are characteristics.

Non-metals and representatives of metal elements - this is the basis on which not only their separation within the table is based, but also the scope of human use. Let us get closer to non-metals and their characteristics.

Position in the periodic system

If we consider the system of chemical elements as a whole, then we can determine the position of non-metals as follows:

1. Upper right corner.
2. Above the conditional boundary diagonal from boron to astatine.
3. The main subgroups are from group IV-VIII.

Obviously, their number is clearly inferior to that of metals. In terms of numbers, this will be approximately 25/85. However, this fact does not in the least diminish their significance and importance. Moreover, the physical properties of non-metals are much more diverse than those of their "opponents."

Varieties of simple non-metal compounds

Several main categories are identified, to which all known elements are considered. Physical properties - non-metals - allow you to divide them into:

• solid;
• gaseous;
• liquid.

Moreover, there is a special group of elements - noble gases. According to their characteristics, they do not belong to any of the designated categories.

Gaseous non-metals

There are a lot of those. These include such simple substances as:

• oxygen;
• nitrogen;
• halogens chlorine and fluorine;
• hydrogen;
• white phosphorus;
• ozone.

However, this is possible subject to standard environmental parameters. The crystal lattice of these representatives is molecular, the type of chemical bond in the molecules is non-polar covalent. The physical properties of the group are similar. They possess:

• compressibility;
• the ability of unlimited mixing among themselves;
• extensibility;
• fill the entire volume of the vessel.

Among the listed substances, two are poisonous - chlorine and Very dangerous, asphyxiating compounds. In this case, chlorine is a yellow-green gas, phosphorus is white, highly flammable in air.

Oxygen and ozone are good oxidizing agents. The first is the constant component of air necessary for the life of most organisms. The second is formed after a thunderstorm due to the action of lightning electrical discharges on atmospheric oxygen. Has a pleasant smell of freshness.

Liquid non-metals

The physical properties of non-metals of this group can be described by characterizing only one substance - bromine. Since only it is a liquid under ordinary conditions among all representatives of the considered group of elements.

This is a dark brown liquid, heavy enough, which is the strongest poison. Even bromine vapors can cause complex ulcers on the hands that do not heal for a long time. Its smell is very unpleasant, for which the element got its name (translated bromos - fetid).

By its chemical characteristics, bromine is an oxidizing agent for metals and a reducing agent for stronger non-metals than it is.

Despite these features, bromine ions must be present in the human body. Without it, diseases associated with hormonal disorders occur.

Solid representatives

Simple substances of this category include most non-metals. It:

• all carbon;
• red and black phosphorus;
• sulfur;
• silicon;
• arsenic;
• one of the tin modifications.

All of them have fairly hard, but brittle substances. Black phosphorus is a dry, greasy to the touch compound. Red is a pasty mass.

The hardest of all these substances is diamond - a kind of carbon. The physical and chemical properties of non-metals of this group are very different, since some of them are located far from each other in the table. Therefore, the oxidation state, the shown chemical activity, the nature of the compounds - all these indicators will vary.

An interesting non-metal in the solid state is iodine. Its crystals shine on the cut, thereby showing similarity with metals. This is not surprising, because it is located almost on the border with them. This substance also has a special property - sublimation. When heated, iodine passes into a gaseous state, bypassing the liquid. Its pairs have a bright purple saturated color.

Physical properties of non-metals: table

In order to more easily indicate what non-metals are, it is better to build a generalizing table. It will show what are the general physical properties of non-metals, and what are their differences.

Obviously, differences in physical properties of non-metals are more prevalent than similarities. If for metals it is possible to distinguish several characteristics under which each of them will fall, then for the elements considered by us this is impossible.

1. The position of metals in the table of elements

Metals are located mainly in the left and lower parts of PSHE. These include:

2. The structure of metal atoms

Metal atoms at the external energy level usually have 1-3 electrons. Their atoms have a large radius and easily give off valence electrons, i.e. exhibit reducing properties.

3. Physical properties of metals

Metal bond   Is the bond that free electrons carry out between cations in a metal crystal lattice.

4. Production of metals

1. Reduction of metals from oxides by coal or carbon monoxide

Me x O y + C \u003d CO 2 + Me or Me x O y + CO \u003d CO 2 + Me

2. Sulfide firing followed by reduction

Stage 1   - Me x S y + O 2 \u003d Me x O y + SO 2

Stage 2 - Me x O y + C \u003d CO 2 + Me or Me x O y + CO \u003d CO 2 + Me

3 Aluminothermy   (reduction by more active metal)

Me x O y + Al \u003d Al 2 O 3 + Me

4. Hydrogenotherm -for high purity metals

Me x O y + H 2 \u003d H 2 O + Me

5. Metal recovery by electric current (electrolysis)

1) Alkaline and alkaline earth metals   get in industry by electrolysis molten salt   (chlorides):

2NaCl - melt, electr. current. →2 Na + Cl 2

CaCl 2 - melt, electr. current.→ Ca + Cl 2

hydroxide melts:

4NaOH - melt, electr. current.→   4 Na + O 2 + 2 H 2 O

2) Aluminum   in industry get as a result of electrolysis molten alumina i am   in cryolite Na 3 AlF 6 (from bauxite):

2Al 2 O 3 - melt in cryolite, electr. current.→   4 Al + 3 O 2

3) Electrolysis of aqueous solutions of salts   use to obtain metals of medium activity and inactive:

2CuSO 4 + 2H 2 O - solution, electr. current.→    2 Cu + O 2 + 2 H 2 SO 4

5. Finding metals in nature

The most common metal in the earth's crust is aluminum. Metals are found both in compounds and in free form.

1. Active - in the form of salts (sulfates, nitrates, chlorides, carbonates)

2. Average her activity   - in the form of oxides, sulfides (Fe 3 O 4, FeS 2)

CHEMICAL PROPERTIES OF METALS

The general chemical properties of metals are presented in the table:

JOBS FOR ATTACHING

No. 1. Finish equations practicable   reactions, name reaction products

Li + H 2 O \u003d

Cu + H 2 O \u003d

Al + H 2 O \u003d

Ba + H 2 O \u003d

Mg + H 2 O \u003d

Ca + HCl \u003d

Na + H 2 SO 4 (K) \u003d

Al + H 2 S \u003d

Ca + H 3 PO 4 \u003d

HCl + Zn \u003d

H 2 SO 4 (k) + Cu \u003d

H 2 S + Mg \u003d

HCl + Cu \u003d

HNO 3 (K) + C u \u003d

H 2 S + Pt \u003d

H 3 PO 4 + Fe \u003d

HNO 3 (p) + Na \u003d

No. 2. Finish UHR, arrange the coefficients by the electronic balance method, indicate the oxidizing agent (reducing agent):

Al + O 2 \u003d

Li + H 2 O \u003d

Na + HNO 3 (k) \u003d

Mg + Pb (NO 3) 2 \u003d

Ni + HCl \u003d

Number 3. Insert the missing characters (<, >   or \u003d)

Number 4. Finish UHR, arrange the coefficients by the electronic balance method, indicate the oxidizing agent (reducing agent):

K + O 2 \u003d

Mg + H 2 O \u003d

Pb + HNO 3 (p) \u003d

Fe + CuCl 2 \u003d

Zn + H 2 SO 4 (p) \u003d

Zn + H 2 SO 4 (k) \u003d

No. 5. Solve the test items

ELEMENT PROPERTIES AND PERIODIC SYSTEM

All elements in the Periodic system are conditionally divided into metals and non-metals. Non-metallic elements include:

Not, Ne, Ar, Kr, Xe, Rn, F, C1, Br, I, At, O, S, Se. Those, N, P, As, C, Si, B, H

All other elements are considered metallic.

Simple substances (elements in free form) are also divided into metals and non-metals, based on their physicochemical properties. So, by physical properties, for example, by electronic conductivity, boron is non-metal, and copper is metal, although exceptions (graphite) are possible.

In the Periodic System, non-metals are elements of the main groups (A-groups), starting from group IIIA (boron); the remaining elements of the A-groups and all the elements of the B-groups are metals. In the main groups, metallic properties are more pronounced for heavier elements, and only metals are included in the 1A-group, and only non-metals in the VPA and VIIIA groups.

In the main groups, the metallic properties of the elements increase, and the non-metallic properties decrease with increasing element serial number.

In periods for elements of the main groups, metallic properties decrease, and non-metallic properties increase with increasing serial number, element.

It follows that the most typical non-metallic element is fluorine, the most typical metal element is France.

In the Periodic system, natural boundaries are clearly visible, relative to which a change in the properties of the elements is observed. Group 1A contains typical metals, Group VIIIA elements (noble gases) are typical non-metals, intermediate groups include non-metals “at the top” of the element table and metals “at the bottom” of the element table. Another boundary between metals and nonmetals corresponds to the elements Be - A1-Ge - Sb - Po (diagonal boundary). Elements of this boundary itself and adjacent to it possess both metallic and nonmetallic properties; amphoteric behavior is characteristic of these elements. Simple substances of these elements can be found both in the form of metallic and non-metallic modifications (allotropic forms).

As a measure of the metallic and non-metallic nature of the elements, we can take the ionization energy of their atoms. Ionization energy is the energy that must be spent to completely remove one electron from an atom. Typically, metals have a relatively low ionization energy (496 kJ / mol for Na, 503 kJ / mol for Ba), and non-metals have a high ionization energy (1680 kJ / mol for F, 1401 kJ / mol for N). The atoms of elements exhibiting amphoteric behavior (Be, A1, Ge, Sb, Po, etc.) correspond to intermediate ionization energies (762 kJ / mol for Ge, 833 kJ / mol for Sb), and the highest values \u200b\u200bfor noble gases (2080 kJ / mol for He, 2372 kJ / mol for He). Within the group of the Periodic System, the values \u200b\u200bof the atomic ionization energy decrease with increasing element serial number, i.e., with increasing atom sizes. Electropositive and electronegative elements. In accordance with the tendency of atoms of elements to form positive and negative monoatomic ions, electropositive and electronegative elements are distinguished.

Atoms of electronegative elements have a high electron affinity. The atoms of such elements hold their own electrons very firmly and tend to accept additional electrons in chemical reactions. Atoms of electropositive elements have low electron affinity. The atoms of such elements weakly retain their own electrons and tend to lose these electrons in chemical reactions.

The most electropositive elements are typical metals (elements 1A of the group), and the most electronegative elements are typical non-metals (elements of the VPA group).

The electropositive nature of the elements increases with the transition from top to bottom within the main groups, and decreases with the transition from left to right within the periods. The electronegative nature of the elements decreases with the transition from top to bottom within the main groups and increases with the transition from left to right within the periods.

The answer should start with characterizing the position of non-metals in the periodic system: if you draw an imaginary diagonal from Be beryllium to At atom, then non-metals will be located in the main subgroups above the diagonal (i.e., in the upper right corner). Non-metals also include hydrogen H and inert gases.

Further, it is important to note that for the general characterization of nonmetals it is necessary to pay attention to the structure of their atoms, to how the electrons are distributed over the electron layers and how many electrons are accounted for by the external electron layer. We can give the structure of carbon atoms C, nitrogen N, oxygen O, fluorine F. This will allow us to conclude that, as the atomic numbers of the elements increase and the electrons accumulate on the outer layer of non-metals of one period, the ability to accept electrons from other atoms to their the outer layer, i.e., non-metallic properties of elements in periods increase.

Considering the change in the properties of non-metals when moving around a group, it should be noted that they are weakening. This is due to an increase in the distance from the nucleus to the outer layer, and therefore, a decrease in the ability of the nucleus to attract electrons to itself from other atoms. To confirm this conclusion, we consider the VI group. At the beginning of it is oxygen O - a typical non-metal, and the group ends with polonium Po, which has the properties of a metal.

Next, we should proceed to consider the physical properties of non-metals. It should be noted that simple non-metal substances can have both atomic (Si, B) and molecular (H2, N2, Br2) structures. Therefore, among non-metals there are gases (O2, C12), liquids (Br2), solids (C, 12). Most non-metals are not electrically conductive, have low thermal conductivity, and solids are non-ductile.

Turning to the characterization of chemical properties, it should be noted that the process of electron reception is more typical for non-metals. This is the difference between the chemical properties of non-metals and the chemical properties of metals. This position can be confirmed by the interaction of non-metals with simple substances. In this case, one should write down the equations of the corresponding chemical reactions and explain their essence from the point of view of oxidation - reduction processes. It should be noted that non-metals can exhibit the properties of both oxidizing agents and reducing agents. Here are some examples.

It can be added that some non-metals can also react with complex substances (oxides, acids, salts). The student gives the following equations at will.

Lesson number 19

Chemistry Grade 9 Date: ____________

Topic:"The position of non-metals in the Periodic system of chemical elements Mendeleev

The purpose of the lesson:To study the situation of non-metals in PSHE.

Tasks:

to study the position of non-metals in the periodic system; structural features of non-metal atoms;

continue to develop the skills of students to work independently with the text of the textbook, compare, analyze, think logically, develop monologic speech, draw independent conclusions and generalize.

to continue the formation of worldview concepts about the cognizability of nature, a causal relationship between the composition, structure, properties and use of substances.

Equipment:   table "Periodic system of chemical elements D.I. Mendeleev "presentation, samples of non-metals.

During the classes

Organizing time

I propose to draw a smile on the issued leaflets with the “face”, if there is a desire to cooperate, and if not, then.

Guessing the topic of the lesson is the challenge stage.

On the board are a series of elements attached with magnets ( chlorine, iron, oxygen, phosphorus, sulfur).

Guys, remove the extra element that violates a certain pattern. (That's right. It's iron.) Why did you remove it?

(That's right, it's metal, and the rest of the elements are non-metals.)

Learning new material.

Of 109 chemical elements, 87 are metals. 22 are non-metals. Non-metals   are chemical elements. which form in free form simple substances that do not have the physical properties of metals

Non-metals are located mainly in the upper right corner of the periodic system, conditionally limited by the diagonal of boron-astatine. The most active is fluorine.

In the period, the charge of the nucleus of the HeMe atom gradually increases, and the size of the atom decreases. In this case, there is a high ability to attach an electron. In this case, oxidizing properties prevail. And for HeMe, which are located in the main subgroup, the smaller the radius of the atom, the stronger the attraction of external electrons. This means that reducing properties prevail here.

??? Where oxidizing properties prevail?

Where are the restorative?

Determine whether sulfur is the oxidizing or reducing agent in the following reactions:

H 2 + S \u003d H 2 S S -

2SO 2 + O 2 → 2SO 3 S -

(Writing the term in a notebook)

Electronegativity   - a measure of nonmetallicity, i.e. the more electronegative a given chemical element, the more pronounced non-metallic properties

View video clip concept of electronegativity.

If metals - simple substances are formed due to a metal bond, then for non-metals - simple substances is characteristic covalent non-polar chemical bond.   In contrast to metals, non-metals - simple substances, are characterized by a wide variety of properties.

No ductility

No shine

Thermal conductivity (graphite only)

The color is diverse: yellow, yellowish green, reddish brown.

Electrical conductivity (graphite and black phosphorus only.)

State of aggregation:

gaseous (H 2, O 2, Cl 2, F 2, O 3)

solid (P, C)

liquid (Br 2)

The ability of atoms of one chemical element to form several simple substances is called allotropy, and these simple substances are called allotropic modifications or modifications. Viewing a video clip (carbon allotropy)

In chemical interactions, non-metals exhibit the properties of both oxidizing agents and reducing agents. Most non-metals react with oxygen to form oxides (1); O 2 - oxidizing agent

2H 2 + O 2 \u003d 2H 2 O + Q S + O 2 \u003d SO 2 + Q C + O 2 \u003d CO 2 + Q

4P + 5O 2 \u003d 2P 2 O 5 + Q N 2 + O 2 \u003d 2 NO - Q

Under various conditions, non-metals react with hydrogen to form volatile hydrogen compounds (2); H 2 - reducing agent

H 2 + S \u003d\u003d H 2 S (at t 0 to 300 0) 3H 2 + N 2 \u003d\u003d 2NH 3 (P, t 0, kat)

H 2 + Cl 2 \u003d\u003d 2HCl (light)

Fastening

Table filling

Orally

Non-metals are found only in the main subgroups.

The number of external electrons in non-metals is less than 3.

Non-metals can exhibit only oxidizing properties.

Under normal conditions, non-metals are only gases.

Non-metals do not conduct electric current

Answers:

Reflection.

Reflexive Test:

1. I learned a lot.

2. It will be useful to me in life.

3. There was something to think about in the lesson.

4. For all questions that arose during the lesson, I received (a) answers.

5. In the lesson I worked in good faith and reached the goal of the lesson.

Task 3

Lesson summary. Grades