Module 06: Lesson 2: Ionic Bonds & Ionic Compounds Notes(pg 173)

​Module 6: Ionic Compounds and Metals (Notes)

Lesson 2: Ionic Bonds and Ionic Compounds (pg 173)

By Catherine LaFever

A. 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 ionic compounds.

If ionic bonds occur between metals and the nonmetal OXYGEN , oxides form. Most other ionic compounds are SALTS.

Multiple Choice

Salts have metallic and nonmetallic elements. Which of these elements has positive charges?

• metallic

• nonmetallic

Multiple Choice

Charges keep a salt ___________.

• together

• separate

Multiple Choice

Which two things can be used to form salts?

• charges and pH

• bases and pH

• acids and pH

• acids and bases

B. Binary Ionic Compounds:

Binary ionic compounds contain a metallic CATION and a nonmetallic anion. Binary means that the compounds contain only TWO (2) different elements.

Ex: Sodium chloride (NaCl) is a binary compound.

C. Properties of Ionic Compounds:

Electrical forces in ionic bonds produce unique physical structures. In an ionic compound, large numbers of positive IONS and negative ions exist together in a ratio determined by the number of electrons transferred from the METAL atom to the nonmetal atom.

C. Properties of Ionic Compounds:

➤ The ions are packed into a regular REPEATING pattern that balances the forces of attraction and repulsion between the ions. The resulting ionic crystal has a highly organized nature with consistent spacing of ions and a UNIFORM pattern.

C. Properties of Ionic Compounds:

➤ The strong attractions among the positive ions and the negative ions in an ionic compound result in the formation of a CRYSTAL lattice, a three-dimensional geometric arrangement of particles.

C. Properties of Ionic Compounds:

➤ Melting point, boiling point, conductivity and hardness are all PHYSICAL properties. They are determined by the strength of electrical forces between particles in matter.

Ionic bonds are relatively strong, so ionic crystals require a lot of energy to break. Thus, the crystals have HIGH melting and boiling points.

C. Properties of Ionic Compounds:

➤ Ionic crystals are hard, BRITTLE solids due to the strong attraction between electric charges that hold the ions in place. This figure shows how and why crystals break when a force strong enough to overcome these attractive forces is applied.

C. Properties of Ionic Compounds:

➤ The ability of a material to conduct electricity depends on the availability of freely moving CHARGED particles. In a solid, ions are locked in position by strong attractive forces. Thus, ionic solids are poor conductors. In ionic compounds in solution or a LIQUID state, ions are free to move. Thus, these compounds conduct electricity. An ionic compound whose aqueous solution conducts an electric current is called an ELECTROLYTE.

Multiple Select

Which of the following are properties of ionic compounds? Choose all correct answers.

• high melting and boiling points

• can be solids, liquids, or gases at room temperature

• tend to be highly flammable

• form crystalline structures

• can conduct electricity when dissolved or melted

Multiple Choice

The following properties are all characteristics of ionic compounds EXCEPT

• high melting and boiling points

• soft

• crystal lattice structure

• conduct electricity when dissolved in water

Multiple Choice

Which of the following is TRUE about ionic compounds?

• They have low melting and boiling points.

• They can conduct electricity in the solid state.

• They are stronger than covalent bonds.

• They are usually formed from 2 metals.

Multiple Choice

Elijah is conducting an experiment in his chemistry class. He observes that a molten (liquefied by heat) compound conducts electricity.

• ionic compound

• molecular compound

D. Energy and the Ionic Bond:

Reactions that ABSORB energy are endothermic.

Reactions that RELEASE energy are exothermic.

D. Energy and the Ionic Bond:

The formation of ionic compounds from positive ions and negative ions is always EXOTHERMIC.

The attraction of the ions forms a more stable system that is LOWER in energy than the individual ions.

The energy required to separate 1 mol of ions of an ionic compound is the LATTICE energy.

Multiple Choice

Bond breaking is ______.

• exothermic

• endothermic

Multiple Choice

Bond making is ______.

• exothermic

• endothermic

E. Lattice Energy:

The strength of the electrical forces holding ions in place is reflected by the lattice energy. The greater the lattice energy, the STRONGER the force of attraction.

Lattice energy is related to ion SIZE.

The electrostatic force of attraction between OPPOSITE charges increases as the distance between the charges DECREASES. (COULOMB'S LAW)

E. Lattice Energy:

Smaller ions form compounds with more closely spaced ionic charges, so they have stronger attractions and greater lattice energies.

Ionic bonds formed from ions with larger positive or negative charges also have GREATER lattice energy.

Multiple Choice

Factors affecting the value of lattice energy

• the size of the ions only

• the charges of the ions only

• BOTH the size of the ions AND the charges of the ions

Multiple Choice

When comparing different ionic compounds, the one with the greater charges will have a _______ magnitude of lattice energy.

• greater

• less

• same

Multiple Choice

When comparing different ionic compounds, the one with the ions of greater size or radius will have a _______ magnitude of lattice energy.

• greater

• smaller

• same

Multiple Choice

Which has the higher lattice energy: BeCl₂ or LiCl?

• LiCl because lithium is smaller than beryllium

• LiCl because Li has a smaller ionic charge than Be

• BeCl₂ because there are more chlorine atoms in the bond

• BeCl₂ because Be has a stronger ionic charge than Li

Multiple Choice

Choose the ionic compound with the greater magnitude of lattice energy.

• NaCl

• CsI

Multiple Choice

Choose the ionic compound with the greater magnitude of lattice energy.

• NaCl

• NaBr

Multiple Choice

Choose the ionic compound with the greater magnitude of lattice energy.

• CaCl₂

• CaS

Reorder

Rank the following compounds in order of increasing lattice energy. (1 = most 3 = least)

• LiF

• NaCl

• KBr

1

2

3

• 1
• 2
• 3