5.2 : Ionic Bonding and Structure

Question 1

Define ionic bonding

Answer 1

The electrostatic attraction between positive and negative ions.

Question 2

What are cations and anions?

Answer 2

Cation : positive ion

Anion : negative ion

Question 3

What kind of dot and cross diagram do you use for ionic bonding?

Answer 3

Outer shell only
Shows electron transfer
Finish with a bracket showing new charge of atom

Question 4

What can ionic bonding happen between?

Answer 4

Metals and non metals

Question 5

What is the structure of ionic compounds?

Answer 5

Giant ionic lattice

Each ion is surrounded by oppositely charged ions

Question 6

Why do ionic compounds have high melting and boiling points ? How can they be made even higher?

Answer 6

High temperatures are needed to provide the large quantity of energy needed to overcome the strong electrostatic attraction between the ions.

The melting / boiling points are higher for lattices containing ions with greater ionic charges, as there is a stronger attraction between ions.

Question 7

Why are ionic compounds soluble?

Answer 7

They dissolve only in polar solvents eg water.

The ionic lattice must be broken down and water molecules must attract and surround the ions.

Question 8

What does solubility depend on?

Answer 8

On the relative strengths of the attractions within the giant ionic lattice and the attractions between ions and water molecules.

Question 9

Describe the electrical conductivity of ionic compounds?

Answer 9

Doesn’t conduct when solid , only when molten or in solution.

Solid : ions are in fixed position so no mobile charge carriers.

Liquid / dissolved : solid ionic lattice breaks down so ions free to move as mobile charge carriers

Question 10

List the properties of ionic compounds

Answer 10

High melting and boiling points
Tend to dissolve in polar solvents such as water
Conduct electricity when liquid or in solution