Characteristic Physical Properties of Halogens

Question 1

What happens to the boiling point of group 7 halogens going down the group?

Answer 1

It increases

Question 2

Explain why the boiling point of group 7 halogens increases going down the group

Answer 2

• As you go down the group, the number of electrons in the molecules increases
• This increases the strength of the London forces between molecules
• This means that more energy is required to break the London forces and so the boiling point increases going down the group.

Question 3

What is the COLOUR and STATEof fluorine at RTP?

Answer 3

A pale yellow gas

Question 4

What is the COLOUR and STATEof chlorine at RTP?

Answer 4

A pale green gas

Question 5

What is the COLOUR and STATEof bromine at RTP?

Answer 5

A red-brown liquid

Question 6

What is the COLOUR and STATEof iodine at RTP?

Answer 6

A grey-black solid

Question 7

How can displacement reactions be used to show the order of reactivity of halogens

Answer 7

• The more reactive halogen is a oxidising agent and displaces the halide ion from the solution to form a halogen
• We can observe which halogens are more reactive than which by observing which halogens displace each halide ions
• When a halogen is formed we can observe a colour change in the solution

Question 8

What do you add in a displacement reaction to distinguish the colours of the hslogens produced?

Answer 8

Cyclohexane

Question 9

What colour is Chlorine in the upper cyclohexane layer?

Answer 9

Pale green

Question 10

What colour is Bromine in the upper cyclohexane layer?

Answer 10

Orange

Question 11

What colour is Iodine in the upper cyclohexane lyer?

Answer 11

Violet

Question 12

What type of reaction is a displacement reaction

Answer 12

REDOX reaction

Question 13

What is a disproportionation reaction?

Answer 13

A reaction where atoms of the same element are both reduce AND oxidised