U5L2

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
Copyright © McGraw-Hill Education

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
Copyright © McGraw-Hill Education

Animation—Ionic Bond Formation in Sodium Chloride

Ionic Bonds and Ionic Compounds
Copyright © McGraw-Hill Education

Go to your ConnectED resources to play Animation: Ionic Bond
Formation in Sodium Chloride.

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
Copyright © McGraw-Hill Education

Properties of 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.

Ionic Bonds and Ionic Compounds
Copyright © McGraw-Hill Education

Properties of Ionic Compounds

•Melting point, boiling point, and hardness depend on the strength of the
attraction.

Ionic Bonds and Ionic Compounds
Copyright © McGraw-Hill Education

Properties of Ionic Compounds

•In a solid, ions are locked into position and electrons cannot flow freely—solid
ions are poor conductors of electricity.

•Liquid ions or ions in aqueous solution have electrons that are free to move, so
they conduct electricity easily.

•An ion in aqueous solution that conducts electricity is an electrolyte.

•This figure demonstrates how and why crystals break when an external force is
applied.

Ionic Bonds and Ionic Compounds
Copyright © McGraw-Hill Education

Energy and the Ionic Bond

•Reactions that absorb energy are endothermic.

•Reactions that release energy are exothermic.

Ionic Bonds and Ionic Compounds
Copyright © McGraw-Hill Education

Energy and the Ionic Bond

•The energy required to separate 1 mol of ions in an ionic compound is referred
to as the lattice energy.

•Lattice energy is directly related to the size of the ions that are bonded.

•Smaller ions form compounds with more closely spaced ionic charges, and
require more energy to separate.

•Electrostatic force of attraction is inversely related to the distance between the
opposite charges.

•The smaller the ion, the greater the attraction.

•The value of lattice energy is also affected by the charge of the ion.

Ionic Bonds and Ionic Compounds
Copyright © McGraw-Hill Education

Energy and the Ionic Bond

Ionic Bonds and Ionic Compounds
Copyright © McGraw-Hill Education

Ionic Bonds and Ionic Compounds
Copyright © McGraw-Hill Education

Review

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?

Vocabulary

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ionic bond

•

ionic compound

•

crystal lattice

•

electrolyte

•

lattice energy