Properties of substancesSG Chemistry, Topic 7

Conductivity of elements and compounds

Standard Grade ChemistryTopic 7

Learning outcomes Success criteriaKnow which elements can conduct electricity. You can write a rule linking the type of element

to whether or not it can conduct electricity.

Given the name of an element, you can state whether or not it can conduct electricity.

Know which types of compound can conduct electricity.

Given the name of a compound, you can state whether it is made up of metal and non-metal elements or only non-metal elements.

You can write a rule linking the types of elements which make up a compound to whether or not it can conduct electricity.

Given the name of a compound and its state, you can state whether it can conduct electricity or not.

Gold

Lead

Sodium

Silicon

Carbon

Iodine

Hydrogen

Bromine

Mercury Sulphur Potassium Phosphorus

• What do the above substances have in common?– Elements

• Which of them conduct electricity?

Gold

Lead

Sodium

Silicon

Carbon

Iodine

Hydrogen

Bromine

Mercury Sulphur Potassium Phosphorus

• What do the above substances have in common?– Elements

• Which of them conduct electricity?– Metal elements and carbon (graphite)

• Does it make a difference what state the elements are in?– No

Graphite and diamond

• Write a rule which summarises which elements can conduct electricity.– All metal elements can conduct

electricity (whether solid or liquid); non-metal elements do not conduct electricity in any state, with the exception of carbon (graphite).

True or false• All solid elements conduct electricity.• All liquid elements conduct electricity.• All metal elements conduct electricity.• No non-metal element conducts electricity.

• Solid oxygen conducts electricity.• Liquid oxygen conducts electricity.• Solid calcium conducts electricity.• Liquid calcium conducts electricity.• Solid carbon conducts electricity.

True or false• All solid elements conduct electricity.• All liquid elements conduct electricity.• All metal elements conduct electricity.• No non-metal element conducts electricity.

• Solid oxygen conducts electricity.• Liquid oxygen conducts electricity.• Solid calcium conducts electricity.• Liquid calcium conducts electricity.• Solid carbon conducts electricity.

Learning outcomes Success criteriaKnow which elements can conduct electricity. You can write a rule linking the type of element

to whether or not it can conduct electricity.

Given the name of an element, you can state whether or not it can conduct electricity.

Know which types of compound can conduct electricity.

Given the name of a compound, you can state whether it is made up of metal and non-metal elements or only non-metal elements.

You can write a rule linking the types of elements which make up a compound to whether or not it can conduct electricity.

Given the name of a compound and its state, you can state whether it can conduct electricity or not.

Practical – conductivity of compounds• If you were to investigate whether a compound can

conduct electricity or not, what equipment would you need?– Power pack / battery– Wires– Bulb

COMPOUND

COMPOUND

Practical – conductivity of compounds• Which compounds would you chose to investigate?

Results• Do compounds of metals/non-metals conduct

electricity when solid?– No

• Do compounds of metals/non-metals conduct electricity when liquid?– Yes

• Do compounds of metals/non-metals conduct electricity when dissolved?– Yes

Results• Do compounds of non-metals/non-metals conduct

electricity when solid?– No

• Do compounds of non-metals/non-metals conduct electricity when liquid?– No

• Do compounds of non-metals/non-metals conduct electricity when dissolved?– No

Do they conduct electricity?• Solid sodium chloride (salt)

• Solid glucose (C6H12O6)

• Liquid potassium iodide• Solid methane• Dissolved lithium nitrate• CaO(s)

• Al(OH)3(l)

• CsCl(aq)

• H2O2(l)

• C12H22O11(aq)

Do they conduct electricity?• Solid sodium chloride (salt)

• Solid glucose (C6H12O6)

• Liquid potassium iodide• Solid methane• Dissolved lithium nitrate• CaO(s)

• Al(OH)3(l)

• CsCl(aq)

• H2O2(l)

• C12H22O11(aq)

Learning outcomes Success criteriaKnow which elements can conduct electricity. You can write a rule linking the type of element

to whether or not it can conduct electricity.

Given the name of an element, you can state whether or not it can conduct electricity.

Know which types of compound can conduct electricity.

Given the name of a compound, you can state whether it is made up of metal and non-metal elements or only non-metal elements.

You can write a rule linking the types of elements which make up a compound to whether or not it can conduct electricity.

Given the name of a compound and its state, you can state whether it can conduct electricity or not.

Ions

Standard Grade ChemistryTopic 7

Learning outcomes Success criteriaUnderstand what ions are. You can define the term ion.

You can describe two ways in which ions can be formed.

For elements 1-20, you can:– name their ions – draw symbols for their ions– draw shell diagrams of their ions– write electron arrangements for their ions

Ion migration

Standard Grade ChemistryTopic 7

Learning outcomes Success criteriaUnderstand what ion migration is. You can explain the results of an ion migration

experiment, including:• specific colours• the direction which these move• ions• positive / negative• attract

Thought experiment

Thought experiment: NaCl(aq)

Concentration (mol/l)

Current (A)

0.00.20.40.60.81.0

0.000.100.160.210.240.27

Thought experiment: C6H12O6(aq)

Concentration (mol/l)

Current (A)

0.00.20.40.60.81.0

0.000.000.000.000.000.00

Why the difference?• Types of elements present?

• Types of particle each is made up of?

Learning outcomes Success criteriaUnderstand what ion migration is. You can explain the results of an ion migration

experiment, including:• specific colours• the direction which these move• ions• positive / negative• attract

Electrolysis

Standard Grade ChemistryTopic 7

Learning outcomes Success criteriaUnderstand what electrolysis is. You can define the term “electrolysis”.

You can name the type of energy which changes a chemical during electrolysis.

From the name of a compound, you can– name the ion which will move to each electrode – state which ion gains electrons and which ion loses electrons– name the substance that will be produced at each electrode

Learning outcomes Success criteriaKnow what an electrolyte is. You can define the term “electrolyte”.

You can identify a substance as a electrolyte or not.

Understand why a d.c. supply must be used during electrolysis.

You can state what “d.c.” stands for.

You can state why a d.c. supply must be used.

Theory of dissolving / melting

+ -+

+-

-

+

+-

+

++

---

+

-+

-

Electrolysis

+

+

+

+

-

---

+ -

-

+

-+

++

+-

-

-

-

+ Copper

Chloride Why must a d.c. power supply be used?

What happens to the mass of each electrode?

Chemistry of electrolysis

Substance +ve electrode

Ion-electron equation

-ve electrode

Ion-electron equation

Aluminium iodide (molten)

Zinc bromide (solution)

Iron(II) chloride (solution)

Learning outcomes Success criteriaUnderstand what electrolysis is. You can define the term “electrolysis”.

You can name the type of energy which changes a chemical during electrolysis.

From the name of a compound, you can– name the ion which will move to each electrode – state which ion gains electrons and which ion loses electrons– name the substance that will be produced at each electrode

Learning outcomes Success criteriaKnow what an electrolyte is. You can define the term “electrolyte”.

You can identify a substance as a electrolyte or not.

Understand why a d.c. supply must be used during electrolysis.

You can state what “d.c.” stands for.

You can state why a d.c. supply must be used.

Why can ionic compounds conduct electricity?

Standard Grade ChemistryTopic 7

Learning outcomes Success criteriaUnderstand what an electric current is. You can describe what an electric current is in

terms of:– charged particles– movement

You can state the three examples of situations in which an electric current can flow.

Learning outcomes Success criteriaUnderstand how a current can flow in solutions or melts.

You can state the name of the charged particles which can flow in solutions/melts.

You can state what charge these particles can have.

You can state where these charged particles come from.

Conduction and molecules

Solid

Particles can’t move freely Liquid or solution

Particles can move freelyDoes not conduct – no charged particles Does not conduct

– no charged particles

Conduction and ions

+ -+

+-

-

+

+-

+

++

---

+

-+

-Solid

Particles can’t move freely Liquid or solution

Particles can move freelyDoes not conduct – ions can’t move freely Conducts

– ions can move freely

The rule• To conduct, charged particles must be

able to move freely.– In compounds, the charged particles are

ions.– The compound must be a liquid (melt) or

dissolved to conduct.

Learning outcomes Success criteriaUnderstand how a current flows in wires. You can state the name of the charged

particles which can flow in wires.

You can state what charge these particles have.

You can state where these charged particles come from.

Types of bonding and structure

Standard Grade ChemistryTopic 7

Covalent bonding• What is a covalent bond?

• In what types of substance do we get covalent bonds?

• Examples?

• What do we know about substances with covalent bonding and their ability to conduct electricity?

Ionic bonding• In what types of substance do we get

ionic bonds?

• Examples?

• What do we know about substances with ionic bonding and their ability to conduct electricity?

Reading, note taking, questions• Standard Grade Chemistry textbook,

p66-67

• Assessment Test 7.1 and 7.2