Part I

1. Atoms of metals, giving up external electrons, turn into positive ions:

where n is the number of electrons in the outer layer of the atom, corresponding to the group number of the chemical element.

2. Atoms of non-metals, accepting electrons missing before the completion of the outer electron layer, are converted into negative ions:

3. A bond arises between oppositely charged ions, which is called ionic.

4. Complete the table "Ionic bond".

Part II

1. Complete the schemes for the formation of positively charged ions. From the letters corresponding to the correct answers, you will form the name of one of the oldest natural dyes: indigo.

2. Play tic-tac-toe. Show the winning path that the formulas of substances with an ionic chemical bond make up.

3. Are the following statements true?

3) only B is true

4. Underline the pairs of chemical elements between which an ionic chemical bond is formed.
1) potassium and oxygen
3) aluminum and fluorine
Draw diagrams for the formation of a chemical bond between the selected elements.

5. Create a comic-style drawing of the formation of an ionic chemical bond.

6. Make a diagram of the formation of two chemical compounds with an ionic bond according to the conditional notation:

Choose chemical elements "A" and "B" from the following list:
calcium, chlorine, potassium, oxygen, nitrogen, aluminum, magnesium, carbon, bromine.
Suitable for this scheme are calcium and chlorine, magnesium and chlorine, calcium and bromine, magnesium and bromine.

7. Write a short literary work (essay, short story or poem) about one of the ionic bond substances that a person uses in everyday life or at work. Use the Internet to complete the task.
Sodium chloride is a substance with an ionic bond, without it there is no life, although when there is a lot of it, this is also not good. There is even such a folk tale, which tells that the princess loved her father the king as much as salt, for which she was expelled from the kingdom. But, when the king once tried food without salt and realized that it was impossible, he then realized that his daughter loved him very much. This means that salt is life, but its consumption should be in
measure. Because too much salt is bad for your health. Excess salt in the body leads to kidney disease, changes skin color, retains excess fluid in the body, which leads to edema and stress on the heart. Therefore, you need to control your salt intake. 0.9% sodium chloride solution is a saline solution used to infuse drugs into the body. Therefore, it is very difficult to answer the question: is salt useful or harmful? We need her in moderation.

Help is on the way, hold on.
a) Consider the formation of an ionic bond between sodium and
oxygen.
1. Sodium - an element of the main subgroup of group I, a metal. It is easier for its atom to give the I outer electron than to accept the missing 7:

1. Oxygen is an element of the main subgroup of group VI, non-metal.
It is easier for its atom to accept 2 electrons, which are not enough to complete the outer level, than to give 6 electrons from the outer level.

1. First, we find the least common multiple between the charges of the formed ions, it is equal to 2(2∙1). In order for Na atoms to give up 2 electrons, they must be taken 2 (2: 1), in order for oxygen atoms to be able to accept 2 electrons, they must be taken 1.
2. Schematically, the formation of an ionic bond between sodium and oxygen atoms can be written as follows:

b) Consider the scheme for the formation of an ionic bond between lithium and phosphorus atoms.
I. Lithium - an element of group I of the main subgroup, a metal. It is easier for its atom to donate 1 outer electron than to accept the missing 7:

2. Chlorine - an element of the main subgroup of group VII, non-metal. His
It is easier for an atom to accept 1 electron than to donate 7 electrons:

2. Least common multiple of 1, i.e. in order for 1 atom of lithium to give away, and a chlorine atom to accept 1 electron, you need to take them one at a time.
3. Schematically, the formation of an ionic bond between lithium and chlorine atoms can be written as follows:

c) Consider the scheme for the formation of an ionic bond between atoms
magnesium and fluorine.
1. Magnesium is an element of group II of the main subgroup, a metal. His
it is easier for an atom to donate 2 outer electrons than to accept the missing 6:

2. Fluorine - an element of the main subgroup of group VII, non-metal. His
it is easier for an atom to accept 1 electron, which is not enough to complete the outer level, than to give 7 electrons:

2. Find the least common multiple between the charges of the formed ions, it is equal to 2(2∙1). For magnesium atoms to donate 2 electrons, only one atom is needed, so that fluorine atoms can accept 2 electrons, they need to be taken 2 (2: 1).
3. Schematically, the formation of an ionic bond between lithium and phosphorus atoms can be written as follows:

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Lesson Objectives:

• To form the concept of chemical bonds using the example of an ionic bond. To achieve an understanding of the formation of an ionic bond as an extreme case of a polar one.
• During the lesson, ensure the assimilation of the following basic concepts: ions (cation, anion), ionic bond.
• To develop the mental activity of students through the creation of a problem situation when studying new material.

Tasks:

• learn to recognize the types of chemical bonds;
• repeat the structure of the atom;
• to investigate the mechanism of formation of ionic chemical bond;
• teach how to draw up formation schemes and electronic formulas of ionic compounds, reaction equations with the designation of the transition of electrons.

Equipment Keywords: computer, projector, multimedia resource, periodic system of chemical elements D.I. Mendeleev, table "Ionic bond".

Lesson type: Formation of new knowledge.

Type of lesson: multimedia lesson.

X one lesson

I.Organizing time.

II . Checking homework.

Teacher: How can atoms take on stable electronic configurations? What are the ways of forming a covalent bond?

Student: Polar and non-polar covalent bonds are formed by the exchange mechanism. The exchange mechanism includes cases when one electron is involved in the formation of an electron pair from each atom. For example, hydrogen: (slide 2)

The bond arises due to the formation of a common electron pair due to the union of unpaired electrons. Each atom has one s-electron. The H atoms are equivalent and the pairs equally belong to both atoms. Therefore, the formation of common electron pairs (overlapping p-electron clouds) occurs during the formation of the F 2 molecule. (slide 3)

H entry · means that the hydrogen atom has 1 electron on the outer electron layer. The record shows that there are 7 electrons on the outer electron layer of the fluorine atom.

During the formation of the N 2 molecule. 3 common electron pairs are formed. The p-orbitals overlap. (slide 4)

The bond is called non-polar.

Teacher: We have now considered cases when molecules of a simple substance are formed. But there are many substances around us, a complex structure. Let's take a hydrogen fluoride molecule. How does the formation of a connection take place in this case?

Student: When a hydrogen fluoride molecule is formed, the orbital of the s-electron of hydrogen and the orbital of the p-electron of fluorine H-F overlap. (slide 5)

The bonding electron pair is shifted to the fluorine atom, resulting in the formation dipole. Connection called polar.

III. Knowledge update.

Teacher: A chemical bond arises as a result of changes that occur with the outer electron shells of the connecting atoms. This is possible because the outer electron layers are not complete in elements other than inert gases. The chemical bond is explained by the desire of atoms to acquire a stable electronic configuration, similar to the configuration of the "nearest" inert gas to them.

Teacher: Write down a diagram of the electronic structure of the sodium atom (at the blackboard). (slide 6)

Student: To achieve the stability of the electron shell, the sodium atom must either give up one electron or accept seven. Sodium will easily give up its electron far from the nucleus and weakly bound to it.

Teacher: Make a diagram of the recoil of an electron.

Na° - 1ē → Na+ = Ne

Teacher: Write down a diagram of the electronic structure of the fluorine atom (at the blackboard).

Teacher: How to achieve the completion of the filling of the electronic layer?

Student: To achieve the stability of the electron shell, the fluorine atom must either give up seven electrons or accept one. It is energetically more favorable for fluorine to accept an electron.

Teacher: Make a scheme for receiving an electron.

F° + 1ē → F- = Ne

IV. Learning new material.

The teacher addresses a question to the class in which the task of the lesson is set:

Are there other options in which atoms can take on stable electronic configurations? What are the ways of formation of such bonds?

Today we will consider one of the types of bonds - ionic bonds. Let us compare the structure of the electron shells of the already named atoms and inert gases.

Conversation with the class.

Teacher: What charge did the sodium and fluorine atoms have before the reaction?

Student: The atoms of sodium and fluorine are electrically neutral, because. the charges of their nuclei are balanced by electrons revolving around the nucleus.

Teacher: What happens between atoms when giving and receiving electrons?

Student: Atoms acquire charges.

The teacher gives explanations: In the formula of an ion, its charge is additionally recorded. To do this, use the superscript. In it, a number indicates the amount of charge (they do not write a unit), and then a sign (plus or minus). For example, a Sodium ion with a charge of +1 has the formula Na + (read "sodium plus"), a Fluorine ion with a charge of -1 - F - ("fluorine minus"), a hydroxide ion with a charge of -1 - OH - (" o-ash-minus"), a carbonate ion with a charge of -2 - CO 3 2- ("tse-o-three-two-minus").

In the formulas of ionic compounds, first write down, without indicating the charges, positively charged ions, and then - negatively charged. If the formula is correct, then the sum of the charges of all ions in it is equal to zero.

positively charged ion called a cation, and a negatively charged ion-anion.

Teacher: We write the definition in workbooks:

And he is a charged particle into which an atom turns into as a result of receiving or giving off electrons.

Teacher: How to determine the charge of the calcium ion Ca 2+?

Student: An ion is an electrically charged particle formed as a result of the loss or gain of one or more electrons by an atom. Calcium has two electrons in the last electronic level, the ionization of a calcium atom occurs when two electrons are given away. Ca 2+ is a doubly charged cation.

Teacher: What happens to the radii of these ions?

During the transition electrically neutral atom into an ionic state, the particle size changes greatly. An atom, giving up its valence electrons, turns into a more compact particle - a cation. For example, during the transition of a sodium atom to the Na+ cation, which, as indicated above, has a neon structure, the radius of the particle is greatly reduced. The radius of an anion is always greater than the radius of the corresponding electrically neutral atom.

Teacher: What happens to oppositely charged particles?

Student: Oppositely charged sodium and fluorine ions, resulting from the transition of an electron from a sodium atom to a fluorine atom, are mutually attracted and form sodium fluoride. (slide 7)

Na + + F - = NaF

The scheme of formation of ions that we have considered shows how a chemical bond is formed between the sodium atom and the fluorine atom, which is called ionic.

Ionic bond- a chemical bond formed by the electrostatic attraction of oppositely charged ions to each other.

The compounds that form in this case are called ionic compounds.

V. Consolidation of new material.

Tasks to consolidate knowledge and skills

1. Compare the structure of the electron shells of the calcium atom and the calcium cation, the chlorine atom and the chloride anion:

Comment on the formation of an ionic bond in calcium chloride:

2. To complete this task, you need to divide into groups of 3-4 people. Each member of the group considers one example and presents the results to the whole group.

Students response:

1. Calcium is an element of the main subgroup of group II, a metal. It is easier for its atom to donate two outer electrons than to accept the missing six:

2. Chlorine is an element of the main subgroup of group VII, a non-metal. It is easier for its atom to accept one electron, which it lacks before the completion of the outer level, than to give up seven electrons from the outer level:

3. First, find the least common multiple between the charges of the formed ions, it is equal to 2 (2x1). Then we determine how many calcium atoms need to be taken so that they donate two electrons, that is, one Ca atom and two CI atoms must be taken.

4. Schematically, the formation of an ionic bond between calcium and chlorine atoms can be written: (slide 8)

Ca 2+ + 2CI - → CaCI 2

Tasks for self-control

1. Based on the scheme for the formation of a chemical compound, make up an equation for a chemical reaction: (slide 9)

2. Based on the scheme for the formation of a chemical compound, make up an equation for a chemical reaction: (slide 10)

3. A scheme for the formation of a chemical compound is given: (slide 11)

Choose a pair of chemical elements whose atoms can interact in accordance with this scheme:

a) Na and O;
b) Li and F;
in) K and O;
G) Na and F

This lesson is devoted to the generalization and systematization of knowledge about the types of chemical bonds. During the lesson, schemes for the formation of chemical bonds in various substances will be considered. The lesson will help to consolidate the ability to determine the type of chemical bond in a substance by its chemical formula.

Topic: Chemical bond. Electrolytic dissociation

Lesson: Schemes for the formation of substances with different types of bonds

Rice. 1. Scheme of bond formation in a fluorine molecule

The fluorine molecule consists of two atoms of the same non-metal chemical element with the same electronegativity, therefore, a covalent non-polar bond is realized in this substance. Let us depict the scheme of bond formation in a fluorine molecule. Rice. one.

Around each fluorine atom, using dots, we draw seven valence, that is, external, electrons. Before a steady state, each atom needs one more electron. Thus, one common electron pair is formed. Replacing it with a dash, we will depict the graphic formula of the fluorine molecule F-F.

Conclusion:a covalent non-polar bond is formed between the molecules of one chemical element-non-metal. With this type of chemical bond, common electron pairs are formed that equally belong to both atoms, that is, there is no shift in the electron density to any of the atoms of the chemical element

Rice. 2. Scheme of bond formation in a water molecule

The water molecule consists of hydrogen and oxygen atoms - two non-metal elements with different values ​​​​of relative electronegativity, therefore, in this substance there is a covalent polar bond.

Since oxygen is a more electronegative element than hydrogen, shared electron pairs shift towards oxygen. A partial charge arises on the hydrogen atoms, and a partial negative charge on the oxygen atom. Replacing both common electron pairs with dashes, or rather arrows showing the shift in electron density, we write down the graphical formula for water Fig. 2.

Conclusion:a covalent polar bond occurs between atoms of different non-metal elements, that is, with different values ​​of relative electronegativity. With this type of bond, common electron pairs are formed, which are shifted towards a more electronegative element..

1. No. 5,6,7 (p. 145) Rudzitis G.E. Inorganic and organic chemistry. Grade 8: textbook for educational institutions: basic level / G. E. Rudzitis, F.G. Feldman. M.: Enlightenment. 2011 176 pp.: ill.

2. Indicate the particle with the largest and smallest radius: Ar atom, ions: K +, Ca 2+, Cl -. Justify your answer.

3. Name three cations and two anions that have the same electron shell as the F - ion.