Chemistry presentation "Halogens. Halogen compounds"

This lesson is a lesson in mastering new knowledge, it is built on the basis of presentation, all stages of the lesson are followed from checking homework to reflection (consolidating new material). Also contains a video fragment of the experiment “combustion of antimony in chlorine”.

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General characteristics of halogens open lesson in chemistry in 9th grade Prepared by: Vyskrebentseva S.V. Chemistry teacher MBOU Secondary School No. 6 Art. Oktyabrskaya

Lesson objectives: To give an idea of ​​halogens based on their comparative characteristics; Consider simple substances - halogens, their physical and chemical properties; Continue developing the ability to compare the properties of simple substances.

Homework check: testing write down the numbers of properties and characteristics for (1 option) metals, for (2 option) non-metals: Small radius of atoms Large radius of atoms At the external level from 1 to 3 electrons At the external level from 4 to 8 electrons Malleability Metallic luster Gaseous state of aggregation Plasticity Various colors Poor electrical conductivity Solid state of aggregation Good thermal conductivity Good electrical conductivity Pronounced reducing properties Pronounced oxidizing properties Allotropy

Correct answers: metals are characterized by: Small radius of atoms Large radius of atoms On the external level from 1 to 3 electrons On the external level from 4 to 8 electrons Malleability Metallic luster Gaseous state of aggregation Plasticity Various colors Poor electrical conductivity Solid state of aggregation Good thermal conductivity Good electrical conductivity Pronounced reduction properties Pronounced oxidizing properties Allotropy

Correct answers: non-metals are characterized by: Small radius of atoms Large radius of atoms On the external level from 1 to 3 electrons On the external level from 4 to 8 electrons Malleability Metallic luster Gaseous state of aggregation Plasticity Various colors Poor electrical conductivity Solid state of aggregation Good thermal conductivity Good electrical conductivity Pronounced reduction properties Pronounced oxidizing properties Allotropy

Chain of transformations: H 2 → NaH → H 2 → HCl NaOH H 2 + 2Na = 2NaH NaH + HCl = NaCl + H 2 H 2 + Cl 2 = 2HCl NaH + H 2 O = NaOH + H 2 2NaOH + 2Al + 6H 2 O = 2Na +3H 2

Problem No. 2 p. 93 Given: Solution: V(air)=100 l V (O 2)= V(air) * ᵠ (O 2)= 100*0.21= ᵠ (O 2)=21% 21 l. ᵠ (N 2) = 78% n (O 2) = V/ V m = 21 l / 22.4 l/mol = 0.94 mol n (O 2) =? V(N 2) = 100*0.78 = 78 l n (N 2) =? n (N 2) = 78L / 22.4L/mol = 3.48mol Answer: 0.94 mol, 3.48 mol.

Problem No. 3 p. 103 Given: Solution: m tech. (WO 3) = 928 kg W (WO 3) = 100% -25% = 75% W (impurity) = 25% m (WO 3) = m tech. * W (WO 3) = V (H 2) =? 928kg * 0.75 = 696 kg n(W)=? n(WO 3) = m/M = 696 kg /232 kg/ kmol = = 3 kmol WO 3 + 3H 2 = W + 3H 2 O 1 mol 3 mol 1 mol 3 kmol 9 kmol 3 kmol V(H 2) = nV m = 9 kmol * 22.4 m3/ kmol = 201.6 m3 Answer: 201.6 m3, 3 kmol.

Study of new material: Position in PSHE and structure of atoms: Group VII main subgroup

General characteristics of halogens: there are 7 electrons in the outer level; the radius of atoms increases; o non-metallic properties weaken; o oxidizing capacity decreases. Fluorine is the strongest oxidizing agent (s.o.-1) For the rest: s.o. -1, +1, +3, +5, +7

Halogens are simple substances. Fluorine F 2 is a poisonous gas of light yellow color with a strong irritating odor.

Simple substances - halogens 2. Chlorine Cl 2 - yellow-green gas with a pungent suffocating odor

Simple substances - halogens 3. Bromine Br 2 - a brown liquid with a fetid odor

Simple substances - halogens 4. Iodine I 2 - a black-gray solid with a metallic sheen and a pungent odor

Chemical properties of halogens Interaction with simple substances: a) with hydrogen H 2 H 2 + G 2 = 2НГ b) with metals F 2 reacts even with Au, Ag and Pt when heated

Combustion of antimony in chlorine

Chemical properties of halogens 2. Interaction with complex substances: a) with water 2F 2 + 2H 2 O = 4HF + O 2 b) with metal halides Cl 2 → Br 2 → I 2 oxidizing capacity decreases

Homework: Paragraph 18, tasks after paragraph 18 No. 4,5 Paragraph 20, tasks after paragraph 20 No. 1 Thank you for your attention!

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OPEN LESSON SCRIPT

in chemistry in the 9th grade on the topic:

“GENERAL CHARACTERISTICS OF HALOGENS”

The purpose of the lesson: Give a general description of halogens and consider their physical and

Chemical properties.

Lesson objectives: 1) Continue developing the skills to compare the properties of simple

Substances;

2) To consolidate general ideas about non-metals and their properties;

3) Develop skills in solving problems and composing equations

Chemical reactions involving nonmetals.

Lesson type: lesson in learning new knowledge

Lesson methods: conversation, story, independent work

Equipment: Periodic table of chemical elements D.I. Mendeleev,

Multimedia system, computer.

DURING THE CLASSES:

1. Organizing time.(1-2 min)

Greeting each other, getting ready to work, communicating the topic and goals of today's lesson.

1. Checking homework.(10-12 min)

1. Call 3 people to the board: 1 solves the chain in the middle of the board, 2 behind the boards solve problems:

Chain of transformations:

H2 → NaH → H2 → HCl

NaOH

1. H2 + 2Na = 2NaH
2. NaH + HCl = NaCl + H2
3. H2 + Cl2 = 2HCl
4. NaH + H2O = NaOH + H2
5. 2NaOH + 2Al + 6H2O = 2Na +3H2

Problem No. 2 p.93

Given: Solution:

V(air)=100 l V(O2)= V(air)* ᵠ (O2)= 100*0.21=

ᵠ (O2)=21% 21 l.

ᵠ (N2) = 78% n (O2) = V/ Vm = 21 l / 22.4 l/mol = 0.94 mol

N(O2)=? V(N2) = 100*0.78 = 78 l

N(N2) =? n (N2)=78L / 22.4L/mol = 3.48mol

Answer: 0.94 mol, 3.48 mol.

Problem No. 3 p. 103

Given: Solution:

Mtech.(WO3) =928 kg W(WO3) = 100%-25%=75%

W(impurity) = 25% m (WO3) = mtech. * W (WO3) =

V(H2)=? 928kg * 0.75 = 696 kg

n(W)=? n(WO3)=m/M=696kg/232kg/kmol = 3 kmol

WO3 + 3H2 = W + 3H2O

1 mole 3 mole 1 mole

3 kmol 9 kmol 3 kmol

V(H2)= nVm = 9 kmol * 22.4 m3/kmol = 201.6 m3

Answer: 201.6 m3, 3 kmol.

1. Everyone else writes a test: select numbers of properties and characteristics for (1st option) metals, for (2nd option) non-metals:

1. Small atomic radius
2. Large atomic radius
3. At the outer level from 1 to 3 electrons
4. At the outer level there are from 4 to 8 electrons
5. Ductility
6. Metallic shine
7. Gaseous state of aggregation
8. Plastic
9. Various colors
10. Poor electrical conductivity
11. Solid state of aggregation
12. Good thermal conductivity
13. Good electrical conductivity
14. Pronounced restorative properties
15. Pronounced oxidizing properties
16. Allotropy

Correct answers: Option 1 – 2,3,5,6,8,11,12,13,14

Option 2 – 1,4,7,9,10,11,15,16

1. Learning new material.(20 minutes)

1. Position in PSHE and structure of their atoms.

Halogens F, Cl, Br, I, At are elements of group 7 of the main subgroup of the Periodic Table of chemistry. elements.

Fluorine is the strongest oxidizing agent (s.o.-1)

For the rest: s.o. -1, +1, +3, +5, +7

In addition to fluorine, chlorine, bromine and iodine, there is another element in this group that belongs to the halogens - astatine. It was predicted by D.I. himself. Mendeleev as eka-iodine, it is a radioactive element, therefore it is not studied in the school course.

1. Halogens - simple substances and their occurrence in nature.

Hearing messages about fluorine, chlorine, bromine and iodine. (4 people, focusing on the presentation slides, talk about halogens, the history of their discovery, and the compounds in which they occur in nature) The rest of the class briefly takes notes on the speakers.

1. Chemical properties of halogens.

1. Interaction with simple substances:

a) with hydrogen H2

H2 + G2 = 2NG

Fluorine reacts with hydrogen under any conditions with an explosion, chlorine reacts with an explosion only when ignited or exposed to direct sunlight, bromine reacts with hydrogen only when heated and without an explosion. These reactions are exothermic, but the reaction of iodine with hydrogen is weakly endothermic; it proceeds slowly even when heated.

b) with metals - salts are formed - metal halides.

So fluoride already under normal conditions it reacts with most metals, and when heated it reacts even with Au, Ag and Pt, known for their chemical passivity.

The remaining halogens react with metals mainly when heated. So, in a flask filled with chlorine, crystals of crushed antimony flare up and burn beautifully:

2Sb + 3Cl 2 = 2SbCl 3 (watching a video clip of the experiment of antimony with chlorine)

2Sb + 5Cl 2 = 2SbCl 5

An independent task is to write the equations for the reactions of iron with chlorine and copper with bromine.

2. Interaction with complex substances:

a) with water

2F2 + 2H2O = 4HF + O2

b) with metal halides(except for fluorine, which primarily interacts with water)

Cl2 → Br2 → I2

oxidizing power decreases from chlorine to iodine:

Cl2 + 2NaBr = 2NaCl + Br2

Br2 + 2KI = 2KBr + I2

1. Consolidation.

(5 minutes.)

1. Answer 5 test questions on the topic studied (see presentation slides) Analysis of grades for the lesson.

(1 min.)

1. Evaluate the respondents at the d/z board who made presentations about halogens. Analysis of grades for the lesson.

Homework:

Paragraph 18, tasks after it No. 4,5

Paragraph 20, task after it No. 1

Degtyareva M.O.

Moscow region

• Korolev AOU LNIP

The elements of group VII, the main subgroup, include fluorine F , chlorine Cl , bromine Br , iodine I , astatine

• At Common name - ( halogens . Greek ) - most of their compounds with metals are typical salts (KCl, NaCl, etc.).

Fluorite CaF 2

Halite NaCl

C ilvinite

KCl NaCl

Atomic radius

Electronegativity

Oxidative properties

Non-metallic properties

Fluorine

Chlorine

Bromine

2 s 2 2p 5

Astatine

3 s 2 3 p 5

4 s 2 4 p 5

5 s 2 5 p 5

6 s 2 6 p 5

+ 9

2 7

2 8 7

2 8 18 7

2 8 18 18 7

2 8 18 32 18 7

• Name "fluorine" (from Greek phthoros - destruction, death)

• Fluorine was obtained in a free state on June 26, 1886 by the French chemist Moissan.

• It is a greenish-yellow gas, slightly heavier than air, with a characteristic odor and extraordinary chemical activity.

• None of the chemical elements

brought chemists so many tragic

events like fluoride .

• Chlorine was discovered by Swedish chemist Carl Scheele in 1774.

• in 1810 Sir Humphry Davy named the gas "Chlorine", from the Greek for "green".
• This term is used in English,

and in other languages ​​the name “chlorine” stuck.

• Yellow-green gas with a pungent odor, poisonous
• 2.5 times heavier than air
• About 2 volumes of chlorine dissolve in 1 volume of water at 20 °C

79 Br ( 50,56% ) 81 Br ( 49,44% )

• from Greek bromos - stench
• the only non-metal that is liquid at room temperature

• heavy red-brown liquid with an unpleasant odor

• bromine vapors are yellow-brown in color
• at a temperature of –7.25° C, bromine solidifies, turning into red-brown needle-shaped crystals with a faint metallic luster

• from Greek iodes - having a violet color
• goes into a vapor state at room temperature without melting (sublimation);
• purple couples

12 6,9

Iodine was discovered in 1811 by Courtois in seaweed ash, and in 1815 Gay-Lussac began to consider it as a chemical element

There are 37 known isotopes of iodine with mass numbers from 108 to 144.

• Halogen molecules consist of two atoms.

, chlorine + , chlorine → Cl Cl

• Bond – covalent nonpolar

• Halogens are typical oxidizing agents

• Oxidizing and non-metallic properties atoms decrease from fluorine to iodine

Oxidative properties

Non-metallic properties

Atomic radius

Fluorine

Chlorine

Bromine

Astatine

+ 9

2 7

2 8 7

2 8 18 7

2 8 18 18 7

2 8 18 32 18 7

• Halogen ions are typical reducing agents

• With hydrogen, halogens form volatile hydrogen compounds

• The stability of hydrogen halides decreases in the following order:

• C sludge of hydrohalic acids increases in the series:

• 3s 2 Zr 5

oxidizer

reducing agent

Oxidation states

HCl NaCl MgCl 2

+ 3

HClO 2

reducing agent

• External electronic configuration of the Cl atom 3s 2 Zr 5

Oxidation states

HCl NaCl MgCl 2

+ 3

HClO 2

+ 5

HClO 3

+ 7

HClO 4

1. Interaction with metals

Chlorine reacts directly with almost all metals (with some only in the presence of moisture or when heated):

2. Interaction with non-metals

With non-metals (except carbon, nitrogen, oxygen and inert gases), it forms the corresponding chlorides.

3. Interaction with water

with the formation of a mixture of acids

+ 1

hypochlorous

salt

4. Interaction with salts of other halogens

more active halogens displace less active ones from solutions of their salts

5 . Interaction with alkali solutions

with the formation of salts

• In industry: electrolysis of melt or sodium chloride solution
• In the laboratory:

production

medicinal

funds

whitening

paper and fabrics

production

of hydrochloric acid

plastics

rubbers

pesticide

In medicine

- 5% alcohol solution of iodine is used to disinfect the skin around the injury

- In X-ray and tomographic studies, iodine-containing contrast agents are used

In technology

- Halogen lamp - an incandescent lamp with halogen vapor (bromine or iodine) added to the cylinder

- Laser thermonuclear fusion- organoiodine compounds are used for the production of ultra-powerful gas lasers on excited atoms

• What does the name “Halogens” mean?
• What are the similarities in the electronic structure of these elements?
• What redox properties do halogens exhibit?
• Which halogen is the most reactive?
• How does the activity of halogens change down the group?

Textbook "Chemistry-9"

§ 13, 14 p. 71 No. 1 – 4

Slide 2

Lesson Plan

1. Hydrohalic acids. 2. Hydrochloric acid and its properties. 3. Salts of hydrohalic acids. Halides. Qualitative reactions to halide ions. 4. Natural halogen compounds. 5. Reflection. 6. Summing up. 7. Homework.

Slide 3

Hydrogen halides

Н⁺ ª→Г⁻ª Physical properties of NG: HF – liquid HCI, HBr, HI – gases. Toxic!!!

Highly soluble in water B 1 V water - 517 V HCI 9 18.9984 F Fluorine 17 35.453 Cl Chlorine 35 79.904 HF Bromine 53 126.904 I Iodine 85 At Astatine Halogens General formula H⁺ G⁻ HF HCI HBr HI K.P.S. HCl Hydrochloric acid

Slide 4

Determine the oxidation states of chlorine in its compounds

HClOHClO2HClO3HClO4 hypochlorous chloride perchloric acid acid acid acid

Slide 5

Acids

Hydrofluoric acid is hydrofluoric acid. Hydrochloric acid is hydrochloric acid. Hydrobromic acid - HF Hydroiodic acid HCl HBr HI S I L A K I S L O T U V E L I C H I V A E T S I F)) +9 2 8 -1 2 Cl))) +17 8 - 1 8 Br)))) 2 +35 18 8 -1 8 2 I))))) +53 8 -1 18 18 8 ??? INCREASING RION DECREASES CONNECTION STRENGTH

Slide 6

Production of hydrogen chloride (HCI) synthesis from hydrogen and chlorine Industrial method: NaCl + H2SO4 → NaHSO4 + HCl (crystal) (conc.) (crystal) Laboratory method: H2 + Cl2 → 2HCl Cl2 H2O HCl HCl h2 H2SO4 NaCl H2O HCl

Slide 7

Colorless liquid, with a pungent odor, smokes in air M = ? HCl Litmus - red Properties 1. Changes the color of indicators 2. Me (up to H2) 3. Basic oxides 5. Salts (weaker acids) 4. Bases Homework: Create reaction equations confirming the chemical properties of hydrochloric acid

Slide 8

Hydrohalic acids