Урок химии на английском языке

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Lesson: Ionic Bonding
Learning objective: 10.1.4.8 understand that an ionic bond is formed as a result of the electrostatic attraction of oppositely charged ions

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Essential Questions
How do ionic bonds form and how are the ions arranged in an ionic compound?
What can you conclude about the strength of ionic bonds based on the physical properties of ionic compounds?
Is ionic bond formation exothermic or endothermic?
Ionic Bonds and Ionic Compounds

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Metal atoms always have few electrons at the external level (from one to three). naturally, it is easier for them to give up electrons to complete the energy level, and for non-metals that have more than three electrons, it is easier to attach electrons to complete the energy level.
The main characteristic of an atom is the charge of its nucleus, which also determines the radius of the atom. To determine the number of electrons at the external level, it is enough to know the group number.
An ionic bond is formed between a typical metal and a typical nonmetal.
Calcium is located in group IIA, which means that it has two electrons at the external energy level, which are easier to give away than to attach six before the energy level is completed. After that, it becomes a positive ion. Са0 - 2ē → Са2+
For a chlorine atom that has 7 electrons on the outer level, it is easier to attach 1 electron to the end of the level than to give away 7 electrons. After attaching 1 electron, the chlorine atom becomes a negative ion.Cl0 + 1ē → Cl-
Find the smallest common multiple between the formed ions. It is equal to two. Therefore, you need to take 1 atom of calcium and 2 atoms of chlorine. This can be shown schematically as follows:Ca0 + 2Cl0 → Ca2+Cl2-.

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Valence Electrons and Chemical Bonds
A chemical bond is the force that holds two atoms together. Chemical bonds form by the attraction between the positive nucleus of one atom and the negative electrons of another atom. Atoms try to form the octet—the stable arrangement of eight valence electrons in the outer energy level—by gaining or losing valence electrons.

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Positive Ion Formation
A positively charged ion is called a cation. This figure illustrates how sodium loses one valence electron to become a sodium cation.


Ion Formation

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Metal Ions
Metals are reactive because they lose valence electrons easily. This table summarizes the ions formed by metal ions in groups 1, 2, and 13.

Ion Formation

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Negative Ion Formation
An anion is a negatively charged ion.
As shown in the table below, nonmetals gain the number of electrons that when added to their valence electrons, equals 8. Some nonmetals can gain or lose other numbers of electrons to complete an octet.

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Formation of an Ionic Bond
The electrostatic force that holds oppositely charged particles together in an ionic compound is called an ionic bond.
Compounds that contain ionic bonds are called ionic compounds.
Binary ionic compounds contain only two different elements—a metallic cation and a nonmetallic anion.


Ionic Bonds and Ionic Compounds

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Properties of Ionic Compounds
Positive and negative ions exist in a ratio determined by the number of electrons transferred from the metal atom to the non-metal atom. The repeating pattern of particle packing in an ionic compound is called an ionic crystal.



Ionic Bonds and Ionic Compounds
The strong attractions among the positive and negative ions result in the formation of the crystal lattice. A crystal lattice is the three-dimensional geometric arrangement of particles, and is responsible for the structure of many minerals.

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Identify the type of chemical bond in the compounds:
H2S, O2, KCl, CO2, F2, LiF, CaCl2

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W
O
N
D
E
R
F
U
!
L

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Reflection

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Thank you for your work!