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Ionic Bonds and Ionic Compounds

In many coastal countries that have warm, relatively dry climates, salt is produced by the evaporation of seawater. You will learn how cations and anions combine to form stable compounds such as sodium chloride.

7.2

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Ionic Bonds and Ionic Compounds

> Formation of Ionic Compounds

Formation of Ionic CompoundsWhat is the electrical charge of an ionic compound?

Compounds composed of cations and anions are called ionic compounds.

Although they are composed of ions, ionic compounds are electrically neutral.

Aluminum metal and the nonmetal bromine react to form an ionic solid, aluminum bromide.

7.2

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Ionic Bonds and Ionic Compounds

> Formation of Ionic Compounds

Ionic Bonds

The electrostatic forces that hold ions together in ionic compounds are called ionic bonds.

7.2

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Ionic Bonds and Ionic Compounds

> Formation of Ionic Compounds

Formula Units

• A chemical formula shows the kinds and numbers of atoms in the smallest representative unit of a substance.

• A formula unit is the lowest whole-number ratio of ions in an ionic compound.

7.2

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Ionic Bonds and Ionic Compounds

> Formation of Ionic Compounds

NaCl is the chemical formula for sodium chloride.

7.2

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Conceptual Problem 7.2

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Conceptual Problem 7.2

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Conceptual Problem 7.2

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Conceptual Problem 7.2

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Practice Problems for Conceptual Problem 7.2

Problem Solving 7.12 Solve Problem 12 with the help of an interactive guided tutorial.

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Ionic Bonds and Ionic Compounds

> Properties of Ionic Compounds

The orderly arrangement of component ions produces the beauty of crystalline solids.

7.2

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Ionic Bonds and Ionic Compounds

> Properties of Ionic Compounds

The coordination number of an ion is the number of ions of opposite charge that surround the ion in a crystal.

In NaCl, each ion has a coordination number of 6.

7.2

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Ionic Bonds and Ionic Compounds

> Properties of Ionic Compounds

In CsCl, each ion has a coordination number of 8.

In TiO2, each Ti4+ ion has a coordination number of 6, while each O2- ion has a coordination number of 3.

7.2

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1. Which chemical formula is incorrect?

a. KF2

b. CaS

c. MgO

d. NaBr

7.2 Section Quiz.

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2. Ionic compounds can conduct an electric current

a. only when melted.

b. when melted or dissolved in water.

c. only when dissolved in water.

d. when solid or melted.

7.2 Section Quiz.

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3. At room temperature, most ionic compounds are

a. crystalline solids.

b. liquids.

c. gases.

d. soft, low melting-point solids.

7.2 Section Quiz.