Lecture 7.2- Ionic Compounds

Bellwork- Ions

Draw a sketch of the periodic table and label ion charges for groups 1A, 2A, 3A(13), 5A(15), 6A(16), & 7A(17).

Lecture 7.2- Ionic Compounds

Compounds composed of cations and anions are called ionic compounds.

Compounds composed of cations and anions are called ionic compounds.

Ionic compounds are electrically neutral. (positive charges always equal the negative charges)

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

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

An ionic compound is also called a salt.

An ionic compound is also called a salt.Salts contain positive and negative ions that alternate in a perfect 3D pattern called a crystal lattice.

Na Cl

Na+ Cl-

The transfer of an electron from Na to Clcreates an anion and a cation.

Na Cl

Na+ Cl-

The transfer of an electron from Na to Clcreates an anion and a cation.

Na Cl

Na+ Cl-

The transfer of an electron from Na to Clcreates an anion and a cation.

Their opposite charges attract them to each other.

Take an atomic-level look at the formation of KCl.

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

•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.

NaCl is the chemical formula for sodium chloride.

NaCl is the chemical formula for sodium chloride.

NaCl is the chemical formula for sodium chloride.

NaCl is the chemical formula for sodium chloride.

Determining formulas for ionic compounds

Determining formulas for ionic compounds The positive charges must equal the negative charges, because the compound is neutral.

Determining formulas for ionic compounds The positive charges must equal the negative charges, because the compound is neutral. Mg2+ and Cl- make MgCl2

because you need 2 Cl- to cancel the 2+ charge on Mg

What is the formula of a compound containing ions of Al and O?

What is the formula of a compound containing ions of Al and O? Al3+ O2-

What is the formula of a compound containing ions of Al and O? Al3+ O2-

Find the least common multiple! 3+ x 2 = 6+ 2- x 3 = 6-

What is the formula of a compound containing ions of Al and O? Al3+ O2-

Find the least common multiple! 3+ x 2 = 6+ 2- x 3 = 6-So you need 2 Al3+ and 3 O2-

Al2O3

What is the formula of a compound containing ions of Al and O?

Al3+ O2-

Al2O3The charge on one ion becomes the subscript for the other ion!

Most ionic compounds are crystalline solids at room temperature.

Most ionic compounds are crystalline solids at room temperature. Ionic compounds have high melting points.

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

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

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

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

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

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

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

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

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

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

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

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

Simulation 5 Simulate the formation of ionic compounds at the atomic level.

Simulation 5

• 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.

• 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.

Electricity is the directed movement of charged particles.

To conduct electricity, a substance or mixture must contain positive or negative charges that can move freely.

Ionic compounds can conduct an electric current when melted or dissolved in water.

Ionic compounds can conduct an electric current when melted or dissolved in water.

1. Which chemical formula is incorrect?

a. KF2

b. CaS

c. MgO

d. NaBr

7.2 Section Quiz.

1. Which chemical formula is incorrect?

a. KF2

b. CaS

c. MgO

d. NaBr

7.2 Section Quiz.

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.

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.

3. At room temperature, most ionic compounds are

a. crystalline solids.

b. liquids.

c. gases.

d. soft, low melting-point solids.

3. At room temperature, most ionic compounds are

a. crystalline solids.

b. liquids.

c. gases.

d. soft, low melting-point solids.