5.2 Ionic bonding and structure

Question 1

What is ionic bonding

Answer 1

The electrostatic attraction between positive and negative electrons
It holds together cations and anions in ionic compounds
Each ion attracts oppositely charged ions in ALL directions

Question 2

Common cations:

Answer 2

metal ions: eg. Na+, Ca2+, Al3+

ammonium ions: NH4+

Question 3

Common anions

Answer 3

non-metal ions: eg. Cl-, O2-

polyatomic ions: NO3-, SO42-

Question 4

What type of compounds form

Answer 4

Ionic compounds

Form a giant ionic lattice structure

Question 5

What state are most ionic compounds at room temperature

Answer 5

solids

Question 6

Why are most ionic compounds solids at room temperature

Answer 6

There is insufficient energy to overcome the strong electrostatic forces of attraction between the oppositely charged ions in the giant ionic lattice

Question 7

Melting and boiling points of ionic compounds

Answer 7

Most have a high melting and boiling point

Question 8

Which lattices have higher melting points

Answer 8

Lattices which contain ions with greater ionic charges as there is stronger attraction between ions
Can also depend on size of ions

Question 9

Are ionic compounds soluble

Answer 9

Many dissolve in polar solvents such as water

Question 10

How do ionic compounds dissolve

Answer 10

Polar molecules break down the lattice and surround each ion in solution

Question 11

Why are some ionic compounds less soluble than other ionic compounds

Answer 11

In compounds made of ions with large charges, the ionic attraction may be too strong for water to be able to break down the lattice structure

Question 12

Solubility requires two main processes:

Answer 12

The ionic lattice must be broken down

Water molecules must attract and surround the ions

Question 13

Can ionic compounds conduct electricity

Answer 13

Only when molten or dissolved

Does NOT when in solid state

Question 14

Ionic compounds and conducting electricity when solid

Answer 14

DOES NOT HAPPEN
The ions are in a fixed position in the giant ionic lattice
There are no mobile charge carriers
An ionic compound is a non-conductor of electricity in the solid state

Question 15

Ionic compounds and conducting electricity when liquid (molten) or dissolved in water

Answer 15

The solid ionic lattice breaks down
The ions are now free to move as mobile charge carriers
An ionic compounds is a conductor of electricity in liquid and aqueous states

Question 16

Properties of most ionic compounds

Answer 16

Have high melting and boiling points
Tend to dissolve in polar solvents such as water
Conduct electricity only in the liquid or aqueous states