1. Properties of Ionic and Covalent Compounds
Learning Intentions:
I know the type of element present in ionic and covalent compounds
I can carry out an experiment to determine the conductivity of ionic and covalent compounds.
I know why there are differencies in mp and bp with ionic compounds, covalent molecules and covalent networks
Success Criteria:
I can state the properties of covalent and ionic compounds in terms of:
MP and BP
Conductivity
Solubility
Elements present

2. Properties of Ionic and Covalent Compounds
Ionic Compounds - contain a metal and non- metal. - soluble in water but are insoluble in other covalent liquids (hexane and white spirit).

3. Water, hexane and white spirit all have covalent bonding.
Water is an unusual covalent liquid as it is a good solvent for ionic substances.
Most covalent liquids are good solvents for covalent substances.

4. Ionic Compounds
Most ionic compounds dissolve easily in water, when they do the lattice breaks up to form free ions.
The solutions formed will conduct electricity since there are charged particles (ions) which are free to move.

5. Melting ionic compounds also allows them to conduct by freeing their ions to move.
Ionic compounds have high melting points due to the vast number of strong ionic bonds which must be broken - needs a lot of energy.

6. Covalent Compounds - contains only non-metal elements.
- insoluble in water but are soluble in other covalent liquids (hexane and white spirit).

7. Covalent Molecule
A molecule is two or more atoms joined together by covalent bonds. They have weak intermolecular forces between molecules.
Example: water, oxygen or carbon dioxide

8. Weak bonds broken during heating

9. Can be a gas, liquid or solid at room temp. Never conduct
Low mp and bp
Can be a gas, liquid or solid at room temp.
Never conduct
Methane
Covalent molecule

10. Covalent Network A network contains many strong covalent bonds.
Example: Diamond, Graphite

11. Solid at room temperature They never conduct
Very high mp and bp
Solid at room temperature
They never conduct
The only exception to this rule is Graphite

12. Melting and Boiling Point
Metals: high mp and bp, solids at room temp. Mercury is the only exception. Ionic substances: high mp and bp, solids at room temp. Covalent molecules: low mp and bp, can be solids, liquids or gases at room temp. Covalent network: high mp and bp, solids at room temp.

13. Experiment 1: Conductivity of Compounds
The conductivity of different compounds were tested.

14. Substance
State
Conducts (Y/N)
Ionic/ Covalent

15. c c i c c i i i i except graphite i i (s) (l) (aq)
BONDING AND PROPERTIES SUMMARY
Conductivity
c = conductor, i = insulator
Solubility in:
Type of
Bonding
Other covalent liquids
Melting Point
Boiling Point
(s)
(l)
(aq)
Water
Do not form solutions c c
metallic
insoluble
insoluble
high
high i c c
ionic
soluble
insoluble
high
high i i
Covalent molecule i
insoluble
soluble
low
low
Covalent network
i except graphite i i
insoluble
soluble
high
high

16. Substance
Low mp and bp
High mp and bp
Covalent Molecular
Conducts electricity
Only when molten or in solution
Never
Ionic
Covalent Network