Presentation on the topic of non-metals in my house. Presentation on the topic "non-metals"

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Which 2 elements are most common in space?

HYDROGEN AND HELIUM

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A substance that supports combustion and respiration?

OXYGEN

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Lightest gas?

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Arthur Conan Doyle "The Hound of the BASKERVILLES" Find the chemical error:

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Sherlock Holmes: “Phosphorus! A strange mixture...Completely odorless. The corpus delicti is now clear..."

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In air, white phosphorus actually glows in the dark. A little friction is enough for the phosphorus to ignite, releasing a large amount of heat. This means that if phosphorus covered the dog’s fur, it would get burns and die before attacking a person

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What unites all the elements from this series?

H, B, C, O, P, F, S, N, He, Si

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What do all the slides shown have in common?

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What are non-metals?

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Using the experience of everyday life and school knowledge, give examples related to the concept of non-metals.

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What do you know about non-metals?

Write down in your notebooks the questions you want to know about non-metals, using: A) “fine” questions (where, who, what, when, how); B) “thick” questions (why, why)

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In non-metal atoms, the outer electron shell contains many (from 4 to 7) electrons (with the exception of the helium atom, which has 2 electrons)

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And it strives for completion either by accepting the missing electrons (then the non-metal is an oxidizing agent), or by giving up electrons (then the non-metal is a reducing agent).

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If there are 8 electrons in the outer electron shell, it is an inert gas.

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For atoms of non-metal elements in the period with increasing atomic number

the nuclear charge increases; atomic radii decrease; the number of electrons in the outer layer increases; the number of valence electrons increases; electronegativity increases; oxidizing (non-metallic) properties are enhanced (except for elements of group VIIIA).

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For atoms of non-metal elements in a subgroup (in a long-period table - in a group) with increasing atomic number

the nuclear charge increases; the radius of the atom increases; electronegativity decreases; the number of valence electrons does not change; the number of external electrons does not change (with the exception of hydrogen and helium); oxidizing (non-metallic) properties weaken (except for elements of group VIIIA).

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Simple substances.

Most nonmetals are simple substances in which the atoms are linked by covalent bonds; There are no chemical bonds in noble gases. Non-metals include both molecular and non-molecular substances. All this leads to the fact that there are no physical properties characteristic of all nonmetals.

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Nonmetals in nature

Native non-metals N2 and O2 (in the air), sulfur (in the earth’s crust) are found in nature, but more often non-metals in nature are found in a chemically bound form. First of all, it is water and salts dissolved in it, then minerals and rocks (for example, various silicates, aluminosilicates, phosphates, borates, sulfates and carbonates). In terms of prevalence in the earth's crust, nonmetals occupy a variety of places: from the three most common elements (O, Si, H) to very rare ones (As, Se, I, Te).

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Oxygen

Oxygen is a colorless gas, while ozone is a pale violet color. Ozone is more bactericidal (Latin icdao - “to kill”) than oxygen. Therefore, ozone is used to disinfect drinking water. Ozone is capable of retaining ultraviolet rays of the solar spectrum, which are destructive to all life on Earth, and therefore the ozone screen, which is located at altitudes of 20-35 km in the atmosphere, protects life on our planet

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Red phosphorus Sulfur Diamond Oxygen

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Phosphorus in nature

Apatite (contains calcium phosphate)

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Carbonates

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The composition of the Earth's inner mantle mainly includes the following elements: MAGNESIUM, SILICON and OXYGEN in the form of compounds Tourmaline Garnet

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Halogens in nature

Fluorine-F2 Fluorite -CaF2 Bromine-Br2 in similar compounds, together with chlorine Chlorine-Cl2 rock salt- NaCl sylvinite –NaCl*KCl Iodine-J2 sea water, algae, drilling water Sodium chloride crystals – mineral halite

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SiO2 SAND CHALcedony QUARTZ ONYX TOPAZ AMETHYST

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Of the 109 chemical elements, 22 are non-metals, located in the upper right corner of the PSHE. Nonmetals are characterized by small atomic radii and a large number of electrons in the last energy level (valence electrons). They give up these electrons with difficulty and easily accept others.

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Chemical bond - covalent non-polar Covalent non-polar bond - is carried out through the formation of common electron pairs between atoms of the same chemical element. Cl - ClH - HO = O

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Inert or noble gases do not form molecules and exist in the atomic state. Many non-metals form a molecule consisting of two atoms (H2, O2, N2, F2, Cl2, Br2, I2) and a very fragile molecular non-polar crystal lattice is formed He - helium, Ne -neon, Ar-argon, Kr-krypton, Xe-xenon, Rn-radon There are non-metals that form the strongest atomic crystal lattices - diamond (C) and silicon (Si)

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At ordinary temperatures, non-metals can be in different states of aggregation: liquid - Br - bromine, solid - S - sulfur, P - phosphorus, I2 - iodine, C - diamond and graphite, gaseous - O2 - oxygen, H2 - hydrogen, N2 - nitrogen, Cl2 -chlorine, F2-fluorine.

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Many do not conduct electricity (except graphite and silicon). They do not conduct heat. In the solid state - brittle Do not have a metallic luster (except for iodine-I2, graphite-C and silicon Si) The color covers all colors of the spectrum (red - red phosphorus, yellow - sulfur, green - chlorine, violet - iodine vapor). The melting point varies over a wide range tmelt (N2) = -210C, and tmelt (Diamond) = 3730C

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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.

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1. molecular structure example: O2 and O3 2. crystal lattice structure example: diamond and graphite

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Allotropic forms of oxygen Oxygen forms two allotropic modifications (the reason is the structure of the molecule) Oxygen O2 A colorless and odorless gas. Part of the air. Non-toxic! Ozone O3 A pale purple gas with a pungent, fresh odor. Has bactericidal properties, able to retain ultraviolet rays

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Allotropic modifications of carbon Carbon forms two allotropic forms (the reason is the structure of the crystal lattice) Diamond Tetrahedral crystal. lattice Colorless crystals The hardest substance in nature tmp=37300C Graphite The crystal lattice resembles a honeycomb Layered crystalline substance Fatty to the touch opaque, gray in color

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Allotropic modifications of phosphorus Phosphorus forms seven allotropic modifications, the reason being the structure of the crystal lattice. The most famous are two allotropic modifications White phosphorus (molecular crystal lattice) P4 Soft, colorless substance Glows in the dark Poisonous! Red phosphorus (atomic crystal lattice) Pn amorphous polymeric substance (powder) does not glow in the dark non-toxic

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Do metals have allotropy? It should be noted that allotropic forms are formed not only by non-metals, but also by metals. For example, tin Sn forms two modifications: white-tin (the well-known white, very ductile and soft metal from which tin soldiers are made) At a temperature of -330C, white tin turns into gray (fine-crystalline powder with the properties of a non-metal), this transition is called tin plague.

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Chemical properties of nonmetals They exhibit strong oxidizing properties, but many can also act as reducing agents (exception -F2). Nonmetals form acidic oxides, acids and are included in salts in the form of acidic residues.

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Nonmetals are chemical elements with typically nonmetallic properties that occupy the upper right corner of the Periodic Table.

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Being in nature

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Ca53(F, Cl, OH)APATITE

Amethyst SiO 2

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Physical properties

Physical state: solid. liquid gaseous Color Various Gloss no no Malleability Electrical conductivity black phosphorus graphite Thermal conductivity

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Interaction with metals:

2Na + Cl2 = 2NaCl, Fe + S = FeS, 6Li + N2 = 2Li3N, 2Ca + O2 = 2CaO In these cases, non-metals exhibit oxidizing properties; they accept electrons, forming negatively charged particles.

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Interaction with other non-metals:

interacting with hydrogen, most non-metals exhibit oxidizing properties, forming volatile hydrogen compounds - covalent hydrides: 3H2 + N2 = 2NH3, H2 + Br2 = 2HBr; interacting with oxygen, all non-metals, except fluorine, exhibit reducing properties: S + O2 = SO2, 4P + 5O2 = 2P2O5;

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when interacting with fluorine, fluorine is an oxidizing agent, and oxygen is a reducing agent: 2F2 + O2 = 2OF2; non-metals interact with each other, the more electronegative metal plays the role of an oxidizing agent: S + 3F2 = SF6, C + 2Cl2 = CCl4.

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Obtaining non-metals

Methods for obtaining nonmetals are diverse and specific; there are no general approaches. Let's look at the main methods for producing some non-metals. Production of halogens. The most active halogens - fluorine and chlorine - are obtained by electrolysis. Fluorine - by electrolysis of the KHF2 melt, chlorine - by electrolysis of the melt or solution of sodium chloride. Other halogens can also be produced by electrolysis or by displacement from their salts in solution using a more active halogen: Cl2 + 2NaI = 2NaCl + I2.

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Hydrogen production. The main industrial method for producing hydrogen is methane conversion (catalytic process): CH4 + H2O = CO + 3H2. Preparation of silicon. Silicon is obtained by reduction with coke from silica: SiO2 + 2C = Si + 2CO. Obtaining phosphorus. Phosphorus is obtained by reduction from calcium phosphate, which is part of apatite and phosphorite: Ca3(PO4)2 + 3SiO2 + 5C = 3CaSiO3 + 2P+5CO.

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Oxygen and nitrogen are obtained by fractional distillation of liquid air. Sulfur and carbon occur in nature in native form. Selenium and tellurium are obtained from waste from sulfuric acid production, as these elements occur in nature along with sulfur compounds. Arsenic is obtained from arsenic pyrites according to a complex transformation scheme, including the stages of obtaining the oxide and reducing the oxide with carbon. Boron is obtained by reducing boron oxide with magnesium.

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Application of non-metals

Hydrogen is used in the chemical industry for the synthesis of ammonia, hydrogen chloride and methanol, and is used for the hydrogenation of fats. Hydrogen is used in the chemical industry for the synthesis of ammonia, hydrogen chloride and methanol, and is used for the hydrogenation of fats. Bromine and iodine are used in the synthesis of polymer materials, for the preparation of medicines, etc. Oxygen is used in the combustion of fuel, in the smelting of cast iron and steel, for welding metals, and is necessary for the life of organisms

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Sulfur is used to produce sulfuric acid, make matches, gunpowder, to control agricultural pests and treat certain diseases, in the production of dyes, explosives, and phosphors. Nitrogen and phosphorus are used in the production of mineral fertilizers, nitrogen is used in the synthesis of ammonia, to create an inert atmosphere in lamps, and is used in medicine. Phosphorus is used in the production of phosphoric acid.

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The nonmetallic properties of elements are determined by the ability of atoms to “accept” electrons, i.e. exhibit oxidizing properties when interacting with atoms of other elements. Of all the elements, 22 elements have non-metallic properties, the remaining elements are characterized by metallic properties. A number of elements exhibit amphoteric properties.

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METALS AND NON-METALS In chemistry, it is customary to divide elements into metals and non-metals depending on the chemical and physical properties of simple substances (i.e., on the way in which individual atoms in a simple substance are bonded). If the bond is metallic, then the simple substance is a metal with a set of properties. Nonmetals are much more difficult to define due to their diversity. The criterion can be the absence of ALL (without exception) properties of metals. Thus, non-metals can be: – non-solid substances (under standard conditions - except Hg); – not shiny; – not plastic (this is the main criterion for simple substances) (which means the bond is not metallic)

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The strongest oxidizing agent is fluorine! It oxidizes even water and some noble gases: 2F2 + 2H2O = 4HF + O2 2F2 + Xe = XeF4 The oxidizing properties of non-metals increase in the following order: Si, B, H, P, C, S, I, Br, N, Cl, O , F

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The same pattern in changes in oxidative properties is also characteristic of simple substances of the corresponding elements. It can be observed in reactions with hydrogen: 3H2 + N2 = 2NH3 (t, catalyst) H2 + Cl2 = 2HCl (under illumination - hϑ) H2 + F2 = 2HF (in the dark - explosion) The reducing properties of non-metal atoms are rather weakly expressed and increase from oxygen to silicon: Si, B, H, P, C, S, I, Br, N, Cl, O

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Cl2 + O2 ≠ N2 + O2 = 2NO (only at high t) S + O2 = SO2 (at zero) Noble gases in the form of simple substances are monatomic He, Ne, Ar, etc. Halogens, nitrogen, oxygen, hydrogen as simple substances exist in the form of diatomic molecules F2, Cl2, Br2, I2, N2, O2, H2. Other nonmetals can exist under normal conditions, both in the crystalline state and in the amorphous state. Nonmetals, unlike metals, are poor conductors of heat and electricity.

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Simple substances nonmetals Non-molecular structure C, B, Si These nonmetals have atomic crystal lattices, so they have great hardness and very high melting points Molecular structure F2, O2, Cl2, N2, S8 These nonmetals in the solid state are characterized by molecular crystal lattices. Under normal conditions, these are gases, liquids or solids with low melting points.

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Methods for obtaining nonmetals Historically, quite a number of methods have been developed for isolating nonmetals from the environment. Some non-metals (simple substances) are present in the environment and can simply be extracted. These are primarily the noble gases, oxygen and nitrogen. Deposits of carbon (graphite) and sulfur can be found as simple substances. The remaining non-metals have to be extracted from complex compounds - chemical reactions must be carried out.

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Chemical methods for producing non-metals How to choose the right reagents for a chemical reaction? There are simple rules - for the target element 1. If a non-metal is in a compound in a negative oxidation state, then to obtain a simple substance it is necessary to use oxidizing agents: H2S + O2 → S + H2O 2KBr + Cl2 → Br2 + 2KCl HCl + KMnO4 → Cl2 + KCl + MnCl2 + H2O

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2. If a non-metal is in a compound in a positive oxidation state, then to obtain a simple substance it is necessary to use reducing agents: SiO2 + 2Mg → Si + 2MgO Ca3(PO4)2 + 5C + 3SiO2 → 2P + + 3CaSiO3 + 5CO TeO2 + SO2 + H2O → Te + H2SO4

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Electrochemical methods Changing the oxidation state in the desired direction can also be achieved through the use of electric current (electrolysis): anodic oxidation (A+, anode) 2H2O - 2e- → O2 + 4H+ 2F- - 2e- → F2 (melt) cathodic reduction (K -, cathode) 2H2O + 2e- → H2 + 2OH-

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Decomposition of Compounds Finally, some nonmetals are formed by the decomposition of compounds. To do this, the starting substance must simultaneously contain both an oxidizing agent and a reducing agent: C12H22O11 (sugar) → C + H2O (pyrolysis) KClO3 → KCl + O2 (with MnO2 catalyst) AsH3 → As + H2 (Marsh reaction)

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Chemical properties of nonmetals Nonmetals can exhibit both oxidizing and reducing properties, depending on the chemical transformation in which they take part. The atoms of the most electronegative element - fluorine - are not capable of donating electrons; it always exhibits only oxidizing properties; other elements can also exhibit reducing properties, although to a much lesser extent than metals. The most powerful oxidizing agents are F2, O2 and Cl2; H2, B, C, Si, P, As and Te exhibit predominantly reducing properties. N2, S, I2 have intermediate redox properties.

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Interaction with simple substances 1. Interaction with metals: 2Na + Cl2 = 2NaCl, Fe + S = FeS, 6Li + N2 = 2Li3N, 2Ca + O2 = 2CaO In these cases, non-metals exhibit oxidizing properties

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2. Interaction with other non-metals: interacting with hydrogen, most non-metals exhibit oxidizing properties, forming volatile hydrogen compounds - covalent hydrides: 3H2 + N2 = 2NH3 H2 + Br2 = 2HBr Under normal conditions, these are gases or volatile liquids. Aqueous solutions of hydrogen compounds of non-metals can exhibit both basic properties (NH3, PH3) and acidic properties (HF, HCl, H2S).

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As the nuclear charge increases, the acidic properties of hydrogen compounds of nonmetals in aqueous solutions increase. SiH4 – PH3 – H2S - HCl Hydrogen sulfide acid is a weak acid, hydrochloric acid is a strong acid. Salts of hydrosulfide acid undergo hydrolysis, salts of hydrochloric acid do not undergo hydrolysis: Na2S + H2O ↔ NaHS + NaOH (pH > 7) NaCl + H2O ≠ (pH = 7)

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In the group with increasing nuclear charge, the acidic properties and reducing properties of hydrogen compounds of non-metals increase: HCl + H2SO4 (conc.)≠ 2HBr + H2SO4 (conc.)= Br2 + SO2 + 2H2O 8HI + H2SO4 (conc.)= 4I2 + H2S + 4H2O

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interacting with oxygen, all non-metals, except fluorine, exhibit reducing properties: S + O2 = SO2 4P + 5O2 = 2P2O5 in reactions with fluorine, fluorine is an oxidizing agent, and oxygen is a reducing agent: 2F2 + O2 = 2OF2 non-metals interact with each other, the more electronegative metal plays the role of an oxidizing agent, the less electronegative one plays the role of a reducing agent: S + 3F2 = SF6 C + 2Cl2 = CCl4

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Oxides and hydroxides of non-metals All oxides of non-metals are acidic or non-salt-forming. Non-salt-forming oxides: CO, SiO, N2O, NO Acid properties of oxides and hydroxides increase in the period, and decrease in the group: SiO2 – P2O5 – SO3 – Cl2O7 H2SiO3 – H3PO4 – H2SO4 – HClO4 Acid properties increase НNO3 H3PO4 H3АsO4 Acid properties decrease

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