Open lesson structure of the periodic system. Synopsis of a lesson in Chemistry "Periodic system of chemical elements of D.I. Mendeleev and the structure of the atom." Flight log from _________ student _____________________________

8th grade

Topic: Periodic Law and Periodic Table of Chemicals

Elements of D.I. Mendeleev. Groups and periods.

Target: reveal the meaning of the periodic law and study the patterns of the periodic system of chemical elements.

Tasks: 1) educational:

A) repeat the concept of "chemical element", the forms of its existence and quantitative characteristics, "amphotericity";

B) to form the ability to determine the belonging of chemical elements to metals and non-metals;

C) to form the concept of natural families of elements: halogens and alkali metals;

D) to study the periodic law and regularities of the periodic system - periods and groups;

2) developing:

A) develop cognitive interest students;

B) develop the ability to formulate the most important compounds and characterize the position of a chemical element in the periodic system;

c) develop the ability to work in groups when studying a new topic;

3) educational:

a) to form the basic worldview ideas about the cognizability of inanimate nature;

b) to form the concept of the periodic law as the basic natural law;

c) introduce the role of the great Russian scientist D.I. Mendeleev in the development of chemical science.

This is the first lesson in the study of the section “Structure of the atom. Chemical bond.

Type of lesson: lesson learning a new topic.

Type of lesson: element by element.

Equipment: 1. Stand"Today in class"

Portrait of D.I. Mendeleev.

Glossary of terms: period, group, periodicity, periodic law.

Statements of D.I. Mendeleev about the periodic law:

"Scientific sowing will sprout for the harvest of the people."

“The future does not threaten the periodic law with destruction, but only superstructures and development promises.”

"Knowing the infinite, science itself is infinite."

What to know: 1) periodic law;

2) the structure of the periodic system.

What to be able to: 1) make formulas of compounds;

2) characterize the position of the element in the periodic system.

2. On the board is an epigraph to the lesson:

... And every sign of her raising,

With his harsh genius,

Mendeleev told the world

In nature, understood by him.

A. Chivilikhin.

3. Supporting notes (Appendix 1).

4. Tasks for work in groups (Appendix 2).

5. Cards with symbols of elements.

6. Equipment for demo experience:

portable box, aluminum wire and granules, solutions of aluminum chloride, sodium hydroxide, of hydrochloric acid, 3 test tubes, test tube rack.

1. Variants of Periodic Tables (exhibition).

During the classes:

1.Org. moment.

Hello! Today we will work using reference notes. Please write down your last name, first name and today's date in them. Call the attendants absent.

In the last lessons, we finished studying the topic “Main classes inorganic compounds”, wrote test and analyzed the mistakes made in it. This topic is the basis for work in the lessons in both the 8th and 9th grades.

Today we begin the study of the next large section “Structure of the atom. Chemical bond. The periodic law formulated by D.I. Mendeleev is the foundation of modern chemistry.

In the lesson, we will reveal the meaning of the periodic law and comprehend its patterns. Let's set ourselves specific goals: "What we should know and be able to do by the end of the lesson."

Pay attention to the statements of D.I. Mendeleev about the periodic law and the epigraph to today's lesson.

2. Actualization of reference teeth.

The concept of a chemical element and knowledge of its characteristics.

Frontal conversation and reference summary (task№1).

What is a chemical element? (this is a kind of atoms that have the same properties)

In what forms can it exist? (in the form of a single atom, simple and complex matter)

What groups are simple and complex substances divided into? (metals and non-metals, oxides, bases, acids, salts)

Give examples of the existence of the chemical element hydrogen (single atoms in space, hydrogen and water).

What do you know the quantitative characteristics of atoms? (valency and relative atomic mass)

What is valency? (this is the ability of atoms to attach a certain number of other atoms to themselves)

What does atomic mass show? (it shows how many times the mass of a given atom is greater than the mass of 1/12 of a carbon atom)

3. Learning a new topic.

1) Basic knowledge.Classification of chemical elements into metals and non-metals.

heuristic conversation.

Determine whether a chemical element is a metal or non-metal based on the specified properties.

1. Highest valency for oxygen 2. A simple substance has a characteristic metallic luster, conducts heat and electricity, solid, grey. Oxide and hydroxide exhibit a basic character.
2. The highest valency for oxygen is 4. A simple substance has a metallic luster, is greasy to the touch, conducts heat and electric current, is solid, dark gray in color. The oxide and hydroxide exhibit an acidic character.
3. Highest valency for oxygen 1. A simple substance conducts heat and electric current, is solid, but easily cut with a knife, has a silvery-white color. Oxide and hydroxide exhibit a basic character.
4. The highest valency for oxygen is 6. A simple substance is poorly wetted by water, yellow in color, brittle, and poorly conducts heat and electricity. The oxide and hydroxide exhibit an acidic character.

Reference outline (task№ 2)

Amphoteric - this is the ability of chemical compounds to exhibit both acidic and basic properties, i.e. react with both bases and acids.

Amphoteric compounds form the following chemical elements: beryllium, aluminum, zinc.

Experience: a simple substance - aluminum - a typical metal. Let's confirm amphoteric properties aluminum hydroxide.

AlCl 3 +3NaOH \u003d Al (OH) 3 + 3NaCl

Al(OH) 3 + NaOH=NaAl(OH) 4

Al (OH) 3 + 3HCl \u003d AlCl 3 + 3H 2 O

2) Natural families of elements.

Group work with application 2 (3-5 min).

Discussion: 1st group.

1. What do the physical and chemical properties of alkali metals have in common?

They have a low density and melting point, the same valency, they actively interact with water and oxygen.

1. What patterns of change in physical and chemical properties did you notice in connection with the change in Ar of these metals?

Ar increases, density increases, melting point decreases.

1. What are the general chemical properties of typical metals?

Easily oxidized, forming basic oxides.

1. Why are the metals of this group called alkaline?

These metals are called "alkaline" because most of their compounds are soluble in water. In Slavic, "leach" means "dissolve". This determined the name of this group of metals. When these metals are dissolved in water, soluble hydroxides, called alkalis, are formed.

2 group.

1. What do the physical and chemical properties of halogens have in common?

All of them are colored, interact with hydrogen, metals form salts. Valency for hydrogen 1, for oxygen 7 (except for fluorine).

1. What patterns of change in physical and chemical properties did you notice in connection with the change in Ar halogens?

The aggregate state passes from liquid to solid, the density and boiling point increase.

1. What are the general chemical properties of typical non-metals, which are halogens?

They interact with hydrogen to form volatile hydrogen compounds, and with metals - salts.

1. Why are non-metals of this group called halogens?

The very name halogens in Greek means "salt" - giving birth to salts.

Reference outline (task№ 2).

3) Prerequisites for the discovery of the periodic law.

These families of similar elements were known to scientists even before Mendeleev, but no smooth transition was established. Not all chemical elements could be combined into related groups.

In 1865, Newlands arranged the chemical elements in order of increasing atomic masses. Scientists noticed the periodicity and identified groups of similar elements. Disadvantage: too many exceptions, hence cannot be a law of nature.

4) Periodic law of chemical elements by DIMendeleev.

Reference outline (task№ 2)

In the middle of the 19th century, approximately 60 chemical elements were discovered and studied. Methods for determining atomic mass were known, but they were still roughly measured. For chemists it was difficult task. The Ar of many elements were incorrectly determined, but then no one suspected this.

Therefore, in 1868, any chemist, wishing to arrange cards with the designations of the elements written on them, their atomic weights and chemical propertiesin ascending atomic weight,I should have received something like this:

H Li B C N Be O F Na Mg Al Si P S Cl

1 7 11 12 14 14 16 19 23 24 27 28 31 32 35,5

The facts alone that were known to chemists before Mendeleev, no matter how they were combined, were not enough to discover one of the greatest laws of nature - periodic. It was necessary not only to know the chemical experience accumulated over many centuries, it was necessary to have genius and especially subtle intuition in order to embrace all knowledge and deeply feel the hidden in them regularity.

But continuing to build his table, Mendeleev arranged his cards in a different way.

The name and atomic weight of hydrogen were written on the first card. He placed the second card with lithium under it. In third place, next to lithium, he put a card on which Be was written,

although at the time most chemists considered Be

14. And this is what Mendeleev did: H

Li Be B C N O F

7 9 11 12 14 16 19

Na Mg Al Si P S Cl

23 24 27 28 31 32 35

So, in the vertical rows there were elements similar in properties - the families of alkali metals and halogens.

With this arrangement, the periodicity of the properties of the elements was clearly manifested. In the first two short periods of the periodic table, the elements alternate correctly according to their atomic weight.

Short functions:

Systematic;

descriptive;

predictive.

5) Periodic system of chemical elements of DIMendeleev.

Explanatory story.

Currently, more than 500 variants of the periodic system are known. The most common is the short form, consisting of 7 periods, 8 groups and 10 rows.

The periodic system is a graphical representation of the periodic law. It compactly presents a huge amount of chemical knowledge, their modern classification and systematization.

What is the PS architecture?

Reference outline (task№ 3,4).

The system is called periodic because it represents a set of periods. Each period contains a strictly defined number of elements, begins alkali metal and ends with an inert gas.

2 and 3 by eight, 4 and 5 by eighteen are twin periods.

4. Fixing.

Reference outline (task№ 5).

Self-filling with subsequent verification.

1. Summarizing.

1. Emotional assessments;
2. Conversation: "Have we achieved the results, the tasks set?"
3. Homework (in advance on the board) p. 12 and add. material (read), reference summary No. 2 (to teach), No. 6.7 (in writing).
4. Everything that we have learned today and what we have learned will definitely come in handy in all subsequent lessons.

Annex 1.

Appendix 2

Irkutsk region

Kirensky district

MKOU "school village Makarovo"

2014 year

Teacher: Kozlova T.I.

Chemistry. 8th grade.

Lesson topic: Periodic system of D.I. Mendeleev

The purpose of the lesson: formation of knowledge about the structure of the periodic system and its role in the world chemical community.

Lesson objectives:

to study the structure of ps.h.e.

show the significance of ps.c.e. in the study of chemistry;

get acquainted with modern options periodic systems;

to prove that the p.s.h.e. is a great discovery of Russian science, represented by D.I. Mendeleev;

to form the skills and abilities to use the table to extract the information contained in it;

Basic concepts of the topic:— D.I. Mendeleev

- periodic system

- periods (small and large)

- groups (main and secondary)

- options for s.s.h.e.:

a) short version

b) half-length version

c) long version

Lesson type: combined

Equipment: portrait of D.I. Mendeleev, chemistry textbooks grade 8, grade 11 (G.E. Rudzitis); wall h.s.h.e.D.I. Mendeleev; multimedia textbook in chemistry (8th grade).

During the classes:

1. Organizing time.

2. Updating knowledge:

Information: by the time of the discovery of the periodic law (1896.XIXc.) 63 chemical elements were known. Having studied their features, D.I. Mendeleev formulated the law.

- express survey: formulate the periodic law of D.I. Mendeleev

3. We formulate the topic of the lesson, goal, tasks

Exercise: continue the sentence: “The Periodic Law has become the basis for………”

Therefore, behind the topic of the lesson “The Periodic Law of D.I. Mendeleev”, the theme “?” should follow.(named by students)

— ?: Try to identify the objectives and goals of this lesson

4. Assimilation of new knowledge:

Working with the textbook test § 36 Task: fill in the table by answering the questions posed (the table is attached, see page 5)

Question

Conclusion:

5. Initial verification of the correctness of understanding the new material, correction of knowledge (conversation onstudied issues, using multimedia study guide: Chemistry 8kl).

6. Reflection (testing, using a multimedia tutorial)

7. Summing up the lesson.

8. D/Z § 36 p.125 No. 4

Lesson topic:

Lesson Objectives:

I know

Conclusion: today at the lesson I understood (a)

Marushenko Ekaterina Alexandrovna, teacher of chemistry - biology.

Periodic system of chemical elements. Signs of chemical elements. 8th grade

Target: To give an idea to students about the Periodic law and the Periodic system of chemical elements of D. I. Mendeleev. Working with chemicals.

Tasks:

Educational- To form knowledge about the periodic law and the periodic system of D.I. Mendeleev. To teach students to work with the periodic system (to be able to determine the position of an element in the periodic system, the properties of the element depending on its position in the periodic system).

Educational – Patriotic education, the formation of a natural-scientific picture of the world, environmental education, promoting awareness of the role of chemical knowledge in personality development, overcoming difficulties.

Educational- Develop observation, memory (when studying physical sense periodic law and its graphical display). Develop the ability to compare. To teach students to generalize and draw conclusions, analyze, compose, systematize.

Equipment and reagents: chalk, board, portraits of scientists,Periodic system of chemical elements of D.I. Mendeleev,cards with elements.

Literature:

For the teacher :1) Gabrielyan, O.S., Chemistry course program for grades 8-11 educational institutions./ Gabrielyan, O.S. - M.: Bustard - 2005.-176 p.

For the student : 1) Gabrielyan O.S., / Yashukova A.V., Chemistry Grade 8. Workbook. – M.: Bustard, 2005.-176 p.

2) Gabrielyan O.S. Chemistry grade 8. Textbook for educational institutions. – M.: Bustard, 2005.-266 p.

Progress:

Hello, have a seat. Let's start with those who are absent. Today in the lesson we will get acquainted with the topic: "D.I. Mendeleev's Periodic Table of Chemical Elements." First we write homework: §4, exercise 2 (in writing), learn the signs of the first 20 elements of the periodic system.

II Knowledge update

Let's review the material from the previous lesson. Answer me questions like: what is a chemical reaction, physical phenomenon, chemical element? Give examples. At the end of the lesson, hand over your homework notebooks to me for checking.

III Explanation of new material

1) Acquaintance with the activities of DIMendeleev.

2) Periodic law and Periodic system.

3) Signs of chemical elements.

1) Next year, i.e. in 2014 we will celebrate two chemical dates: 183 years since the birth of D. I. Mendeleev and 148 years since the discovery of his Periodic Law and the Periodic Table of Chemical Elements (March 1, 1869). He was often called a genius, but he did not like it and, as a rule, got angry: “Well, what kind of genius am I? He worked all his life, so he became a genius. D. I. Mendeleev - a brilliant Russian chemist (1834 - 1907). “I myself wonder what I just didn’t do in my scientific life”- D.I. Mendeleev wrote about himself. Throughout his life, he wrote and published 431 works. Mendeleev's student G.G. Gustavson (1842-1908) noted: "Whatever business he touched, he always left deep and instructive traces on it." He loved to read, loved chess and rarely lost.He was a great connoisseur of painting, “he breathed art as well as science, which he considered two sides of our common aspiration to beauty, to eternal harmony, to the highest truth” (from the memoirs of I.D. Mendeleev). Traveled a lot.

2) Everyone knows his Periodic Law and Periodic System. The Periodic Law goes like this: "The properties of the elements, and therefore the simple and complex bodies (substances) formed by them, stand in a periodic dependence on their atomic weight."Modern wording:"the properties of chemical elements (i.e., the properties and form of the compounds they form) are in a periodic dependence on the charge of the nucleus of atoms of chemical elements."March 1, 1869 is considered the birthday of the Periodic Law, and the Periodic System of D.I. Mendeleev is its graphic expression. There are over 400 variants of the Periodic Table of Chemical Elements. Dmitry Ivanovich knew the properties of each chemical element well and arranged them in such a way that he singled out groups of elements similar in chemical properties, and even left places in the table for chemical elements that have not yet been studied. Dmitry Ivanovich foresaw the properties of some not yet discovered elements and pointed out the ways of discovering these elements.Every periodic table shows the same chemical elements in the same order. The genius of this creation lies in the fact that it contains a lot of information about chemical elements, about the patterns of their arrangement, about the structure of atoms of chemical elements, ... Therefore, depicting periodic systems, they try to highlight different semantic categories of elements with color.In our table (on the flyleaf of the textbook), non-metal elements are highlighted in red, and metal elements are highlighted in black and green.Give examples of non-metal elements.Give examples of metal elements. Well done, write down a few examples for yourself.

All known chemical elements are located in the periodic table of D.I. Mendeleev, 118 elements are known. Horizontally, this table consists of periods.Periods - small periods large periods - 2 rows of elements.

Vertically, the periodic table consists of 8 groups.Group - this is a vertical row of elements in the Periodic system of D. I. Mendeleev. Each group, in turn, is divided into two subgroups: main and secondary. Elementsmain subgroup are located in small and large periods, and the elementssecondary subgroup are found only in large periods.SubgroupMain subgroup (A)Side subgroup (B)

3) We will speak with you in a special, chemical language. In it, as in our native Russian, we will first learn letters - chemical symbols, then learn how to write words - formulas based on them, and then, with the help of the latter, - sentences - equations of chemical reactions. And who is the author of the Slavic alphabet?

The Bulgarian educators Cyril and Methodius are the authors of the Slavic script-alphabet. But the father of chemical writing is the Swedish scientist J. Ya. Berzelius, who suggested using the initial letters of their Latin names as letters - symbols of chemical elements, or, if the names of several elements begin with this letter, then add one more to the initial letter subsequent letters of the name.For example, hydrogen is denoted by the letter H (ash), then the next element helium will be denoted by He. The names of the elements have different origins, I will read, and you write down the chemical elements named after Russia and after a city in Russia. For example:

- The table has elements named after mythical heroes. Items such as: Cadmium - discovered in 1818. Since ancient times, zinc carbonate ores have been called the Greek word "cadmeia". The name goes back to the mythical Cadmus (Kadmos) - the hero Greek mythology, the brother of Europe, the king of the Cadmean land, the founder of Thebes, the winner of the dragon, from whose teeth warriors grew.Thorium - in 1828 Y.Ya. Berzelius discovered in a rare mineral sent to him from Norway, a compound of a new element, which he named thorium - in honor of the Old Norse god Thor.Promethium - in 1947, American researchers J. Marinsky, L. Glendenin and C. Coryell, chromatographically separating the fission products of uranium into nuclear reactor. Coriella's wife suggested that the discovered element be named promethium, after Prometheus, who stole fire from the gods and gave it to people. This emphasized the formidable power contained in the nuclear “fire”.

- Elements named after states and geographic features . Ruthenium Germanium - in honor of GermanyGallium, francium - in honor of France
Scandium - in honor of the Scandinavian Peninsula,Europe th - in honor of EuropeAmericium - in honor of America,Polonium - in honor of Poland.

- Elements named after cities : Hafnium - in honor of Copenhagen,Lutetium - in honor of Paris (Lutetia),Berkelium - in honor of the city in the USA,Dubnium Yttrium, terbium, erbium, ytterbium - in honor of the city of Ytterby in Sweden, where a mineral containing these elements was discovered,Holmium - in honor of Stockholm (its old Latin name is Holmia).

- Elements named after explorers : Gadolinium - V In 1794 Finnish chemist and mineralogist Johan Gadolin discovered an oxide of an unknown metal in a mineral found near Ytterby.Fermium and Einsteinium - in 1953, in the products of a thermonuclear explosion that the Americans produced in 1952, isotopes of two new elements were discovered, which were named fermium and einsteinium - in honor of the physicists Enrico Fermi and Albert. Einstein.Curium - the element was obtained in 1944 by a group of American physicists led by Glenn Seaborg by bombarding plutonium with helium nuclei. It was named after Pierre and Marie Curie.Mendelevium - for the first time, the Seaborg group announced its receipt in 1955, but only in 1958 reliable data were obtained at Berkeley. Named after D.I. Mendeleev.

IV Anchoring

1) What topic did we study today?

2) what year are openPeriodic Law and Periodic System? Who opened?

3) What is a period? What are there?

4) Define a group.

V .Conclusions.

We have studied the subject Periodic system of chemical elements. Signs of chemical elements. Learned what a group, period. We got acquainted with such a scientist as D.I. Mendeleev. We got acquainted with some names of chemical elements and in honor of what they were discovered.I think that you did a great job with the study of this topic of the lesson. And having learned the home paragraph and the table with chemical elements, you will perfectly use these concepts in the further study of chemistry.

Goodbye!

Chemical reactions are any chemical phenomena of nature. At chemical reaction there is a rupture of some and the formation of others chemical bonds. As a result of the reaction from one chemical substances other substances are obtained. (Combustion of substances, corrosion of metals).Physical phenomena are substances whose composition remains unchanged, but only its composition changes. state of aggregation or the shape and size of bodies.Chem. An element is a type of atom that has the same properties. In the form of a single atom, simple and complex matter.

1) Write down: D. I. Mendeleev - a brilliant Russian chemist (1834 - 1907). Throughout his life, he wrote and published 431 works.

2) Answering questions: Non-metals - boron, carbon, nitrogen, fluorine, neon, silicon, phosphorus, sulfur, chlorine, argon, arsenic, selenium, bromine, iodine, radon, etc.

Metals - AL, Ba, Fe, K, Ca, Mn, mg, Li, Cu, Na, Niand etc.

Write down: Periods -these are the horizontal rows in the periodic table of chemical elements. Periods are divided into small and large,small periodshave only 1 row of elements, andlargeperiods- 2 rows of elements.Group -this is a vertical row of elements in the Periodic system of D. I. Mendeleev. Each group, in turn, is divided into two subgroups: main and secondary.Subgroup- this is a set of elements that are unconditional chemical analogues; often the elements of a subgroup have the highest oxidation state corresponding to the group number.Main subgroup (A)- a set of chemical elements located vertically and having the same number of electrons at the external energy level (s-, p-elements).Side subgroup (B)- a set of chemical elements located vertically and having the same number of electrons at the outer (n) and pre-outer (n-1) level (d-elements).

3) Answer: Cyril and Methodius.

Write down: ABOUTThe father of chemical writing is the Swedish scientist J. Ya. Berzelius, who proposed to use the initial letters of their Latin names as letters - symbols of chemical elements.

Ruthenium - This metal of the platinum group was discovered by K. K. Klaus in Kazan in 1844 during his analysis of the so-called factory platinum deposits. Klaus isolated the new metal as a sulfide and suggested that it be named ruthenium after Russia.

Dubnium - in honor of the city of Dubna in Russia,

Answer: 1) Periodic system of chemical elements. Signs of chemical elements.2) Periodic Law and Periodic Table of Chemical Elements (March 1, 1869). DI. Mendeleev.3) Periods - these are the horizontal rows in the periodic table of chemical elements.Periods are divided into small and large,small periods have only 1 row of elements, andlarge periods - 2 rows of elements. 4) Group - this is a vertical row of elements in the Periodic system of D. I. Mendeleev.

Hand over notebooks with homework and say goodbye.

Topic: The structure of the periodic table of elements
Tasks:
- to give the concept of the structure of the periodic system, groups, periods;
- continue developing skills and abilities to compare, work independently;
- instill a sense of national pride.
Motivation and goal setting:
"The scientific study of objects has two main or final ends: foresight and utility."
DI. Mendeleev
Learning new material:
DI. Mendeleev developed scientific classification chemical elements - Periodic system in the form of a table. This table can be represented as a house where all the chemical elements "live". Each chemical element has its own “apartment”, i.e. cell with a specific number. For example, calcium "lives" in "apartment" No. 20, i.e. in cell number 20. There are "floors" horizontally in the house. There are only seven of them. In chemistry they are called periods. On the first floor, only 2 chemical elements “live”, on the second and third - 8 each. These periods, or “floors”, are called small. Think why?
Starting from the 4th period, more "residents" appear on each "floor". So, on the 4th and 5th - there are 18 of them, on the 6th - 32, and on the 7th so far all the "residents" have not stopped by. These periods are already called large, because there are so many chemical elements arranged in two rows.
If you were attentive, you noticed that 14 twin elements, similar in their properties, “live” in the “basement floors”. Some are similar to lanthanum and are called, therefore, lanthanides, others are similar to actinium and are called actinides.
Vertically, chemical elements also "live" under each other. These vertical rows are called groups. In these vertical groups, chemical elements have similar properties. There are only 8 of these groups.
Each group consists of two subgroups: main and secondary. The main subgroup is also called group A, it includes elements of small and large periods. The side subgroup is also called group B, it includes elements of only large periods.
Let's look at the main subgroup of group I, it includes Li, Na, K, Rb, Cs, Fr. This is a subgroup of lithium, because lithium is the first in it. The side subgroup of this group is formed by Cu, Ag, Au, therefore it is called the copper subgroup.
In addition to the short period table D.I. Mendeleev, which you have in your textbook, there is also a long-term version (see Fig. 25)
In total, there are 114 chemical elements in the table, and just as 33 letters of the alphabet form a lot of words, so 114 chemical elements form a lot of substances.

Generalization and systematization of knowledge:
What is a period? How many chemical elements include periods 1, 2 and 3? How many elements are in long periods?
What is the group of the periodic system? What do the letters A and B say after the group number?
What is the difference between large and small periods?
Consolidation and control of knowledge:
Name the elements of IVA and VIB groups.
With straight lines, select the rows where there are: a) elements of the same period; b) elements of the same group.
Be Al ClN O Ne
Mg P Ar P Be NaCa Li H As He S
Find in each row one of the elements that differs from the rest in position in the periodic table of chemical elements.
a) H, He, Ne, Arb) H, Li, Be, B
c) Fe, Co, Ni, Arg) F, Cl, Mn, Br
Answers: a) H; b) H; c) Ar; d) Mn.
Select groups of similar elements:
a) Na, Ca, O
b) Ne, Ar, He
c) F, Cl, Br
d) P, B, Li
Answers: b; V.
Reflection and summing up:
The game "Brighter than everyone!".
Students are given leaflets with a set of "stars" of different sizes according to the number of concepts studied and are invited to write what they remember most in the "star" of the corresponding size; what is less - respectively, of a smaller value.
Then the leaflet data is processed by several students and the “brightest star” of this lesson, the most learned concept, is revealed.
Homework:
Level I: §5, ex. 5;
Level II: §5, ex. 5; + report "Discovery of the Periodic Table of Elements".

Attached files

Periodic system of chemical elements of D. I. Mendeleev

Basic concepts:

1. Ordinal number of a chemical element- the number given to the element when it is numbered. Shows the total number of electrons in an atom and the number of protons in the nucleus, determines the charge of the nucleus of an atom of a given chemical element.

2. Period- chemical elements arranged in a line (there are 7 periods in total). The period determines the number of energy levels in an atom.

Small periods (1 - 3) include only s - and p - elements (elements of the main subgroups) and consist of one line; large (4 - 7) include not only s - and p - elements (elements of the main subgroups), but also d - and f - elements (elements of secondary subgroups) and consist of two lines.

3. Groups- chemical elements arranged in a column (only 8 groups). The group determines the number of outer level electrons for elements of the main subgroups, as well as the number of valence electrons in an atom of a chemical element.

Main subgroup (A)– includes elements of large and small periods (only s - and p - elements).

Side subgroup (B)- includes elements of only large periods (only d - or f - elements).

4. Relative atomic mass (A r) – shows how many times a given atom is heavier than 1/12 of a 12 C atom, this is a dimensionless value (for calculations, a rounded value is taken).

5. Isotopes- a variety of atoms of the same chemical element, differing from each other only in their mass, with the same serial number.

The structure of the atom

Basic concepts:

1. Electronic cloud is a model of quantum mechanics that describes the motion of an electron in an atom.

2. Orbital (s, p, d, f) - part of the atomic space in which the probability of finding a given electron is the highest (~ 90%).

3. Energy level- this is an energy layer with a certain energy level of the electrons located on it.

The number of energy levels in an atom of a chemical element is equal to the number of the period in which this element is located.

4. Maximum possible number electrons at a given energy level is determined by the formula:

N = 2 n 2 , where n is the period number

5. The distribution of orbitals by levels is represented by the scheme:

6. Chemical element A type of atom with a certain nuclear charge.

7. Composition atom :

8. Composition atomic nucleus:

The nucleus is made up of elementary particles

protons(p) and neutrons(n).

Since Almost all the mass of an atom is concentrated in the nucleus rounded valueA rof a chemical element is equal to the sum of protons and neutrons in the nucleus.

9. The total number of electrons in the electron shell of an atom is equal to the number of protons in the nucleus and the atomic number of the chemical element.

The order of filling levels and sublevels with electrons

I. The electronic formulas of atoms of chemical elements are in the following order:

First, by the number of the element in the table of D. I. Mendeleev, the total number of electrons in the atom is determined;

Then, according to the number of the period in which the element is located, the number of energy levels is determined;

Levels are divided into sublevels and orbitals, and fill them with electrons in accordance The principle of least energy

For convenience, electrons can be distributed over energy levels using the formula N \u003d 2n 2 and taking into account the fact that:

1. at the elements main subgroups(s -; p -elements) the number of electrons in the outer level is equal to the group number.

2. at the elements side subgroups usually on the outside two electron (with the exception of atoms Cu, Ag, Au, Cr, Nb, Mo, Ru, Rh, whose outer level one electron, at Pd at the outer level zero electrons);

3. The number of electrons in the penultimate level is equal to the total number of electrons in the atom minus the number of electrons in all other levels.

II. The order in which atomic orbitals are filled with electrons is determined by:

1.Principle of least energy

Energy scale:

1s<2s<2p<3s<3p<4s<3d<4p<5s<4d<5p<6s<4f<5d<6p<7s…

2. The state of an atom with a completely or half-filled sublevel (ie, when there is one unpaired electron in each orbital) is more stable.

This explains the "failure" of the electron. Thus, the following distribution of electrons corresponds to the stable state of the chromium atom:

Cr: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 3d 5 , ane 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 4 ,

i.e., there is a "failure" of the electron from the 4s sublevel to the 3d sublevel.

III. Families of chemical elements.

Elements in whose atoms the s-sublevel is filled with electrons external s-elements. These are the first 2 elements of each period, constituting the main subgroups I And II groups.

Elements in whose atoms the p-sublevel is filled with electrons external energy level are called p-elements. These are the last 6 elements of each period (with the exception of I And VII), constituting the main subgroups III- VIII groups.

Elements in which the d-sublevel is filled second outside the level are called d-elements. These are elements of intercalary decades IV, V, VI periods.

Elements in which the f-sublevel is filled third outside the level are called f-elements. The f-elements include lanthanides and actinides.

Periodic law of D. I. Mendeleev

The properties of simple substances, as well as the forms and properties of compounds of elements, are in a periodic dependence on the magnitude of the atomic weights of the elements.

The modern formulation of the periodic law.

The properties of chemical elements and their compounds are in a periodic dependence on the magnitude of the charge of the nuclei of their atoms, which is expressed in the periodic repetition of the structure of the outer valence electron shell.

Key points

1. In the period from left to right:

2) The charge of the nucleus - increases

3) The number of energy levels - constantly

4) The number of electrons at the outer level - increases

5) The radius of atoms - decreases

6) Electronegativity - increases

Consequently, the outer electrons are held tighter, and the metallic (reductive) properties are weakened, while the non-metallic (oxidizing) properties are enhanced.

2. In the group, in the main subgroup from top to bottom:

1) Relative atomic mass - increases

2) The number of electrons in the outer level is constant

3) The charge of the nucleus - increases

4) The number of energy levels - increases

5) Radius of atoms - increases

6) Electronegativity - decreases.

Consequently, external electrons are held weaker, and the metallic (reducing) properties of the elements are enhanced, while the non-metallic (oxidative) properties are weakened.

3. Change in the properties of volatile hydrogen compounds:

1) in groups of main subgroups, with an increase in the charge of the nucleus, the strength of volatile hydrogen compounds decreases, and the acidic properties of their aqueous solutions increase (basic properties decrease);

2) in periods from left to right, the acidic properties of volatile hydrogen compounds in aqueous solutions increase (basic ones decrease), and the strength decreases;

3) in groups with an increase in the charge of the nucleus in the main subgroups, the valency of the element in volatile hydrogen compounds does not change, in periods from left to right it decreases from IV to I.

4. Change in the properties of higher oxides and their corresponding hydroxides (oxygen-containing acids of non-metals and metal bases):

1) in periods from left to right, the properties of higher oxides and their corresponding hydroxides change from basic through amphoteric to acidic;

2) the acidic properties of higher oxides and their corresponding hydroxides increase with increasing nuclear charge in the period, the basic ones decrease, and the strength decreases;

3) in the groups of the main subgroups of higher oxides and their corresponding hydroxides, with an increase in the charge of the nucleus, the strength increases, the acidic properties decrease, the basic ones increase;

4) in groups with an increase in the charge of the nucleus in the main subgroups, the valency of the element in higher oxides does not change, in periods from left to right it increases from I to VIII.

5. Completeness of the outer level - if there are 8 electrons on the outer level of the atom (for hydrogen and helium 2 electrons)

6. Metal properties - the ability of an atom to donate electrons before the completion of the external level.

7. Non-metallic properties - the ability of an atom to accept electrons before the completion of the outer level.

8. Electronegativity the ability of an atom in a molecule to attract electrons to itself

9. Families of elements:

Alkali metals (1 group "A") -Li, Na, K, Rb, Cs, Fr

Halogens (group 7 "A") -F, Cl, Br, I

Inert gases (group 8 "A") -He, Ne, Ar, Xe, Rn

Chalcogens (group 6 "A") -O, S, Se, Te, Po

Alkaline earth metals (group 2 "A") -Ca, Sr, Ba, Ra

10. Radius of an atom is the distance from the nucleus of an atom to the outer level

Tasks for fixing: