ES.1

Question 1

What are halogens?

Answer 1

Halogens are elements from group 7 of the periodic table.

Question 2

What are two ways halogen atoms can achieve its stability by?

Answer 2

1. Gain an electron from a metal atom to form a hallide ion in an ionic compound.
2. Share an electron with a non-metal atom to form a covalently bonded compound. (They also form diatomic molecules with another atom of the same element.)

Question 3

Describe the appearances of the first four halogens at room temperature.

Answer 3

Fluorine: pale yellow gas.
Chlorine: green gas.
Bromine: dark red volatile liquid.
Iodine: shiny grey solid, sumblimes to give purple vapour when heated.

Question 4

List trends of properties as you go down the group. (3p)

Answer 4

• Higher melting and boiling points (bigger id-id intermolecular forces).
• Less volatile.
• Less reactive.

Question 5

What can you say about the solubility of halogens? (3p)

Answer 5

• Halogens are generally not very soluble in water.
• Fluorine reacts with water.
• Halogens are generally quite soluble in organic solvents.

Question 6

What is halogens often refer to as in a redox reaction?

Answer 6

The oxidising agent.

Question 7

What is it called when an atom loses an electron?

Answer 7

We say it is oxidised.

Question 8

What is it called when an atom gains an electron?

Answer 8

We say it is reduced.

Question 9

What are the ions called that are left out of the ionic equation of a reaction because they are unchanged?

Answer 9

Spectator ions.

Question 10

What is it meant by a displacement reaction?

Answer 10

This is when a halogen displaces a less reactive halogen from a compound.

Question 11

What is it meant by a redox reaction?

Answer 11

This is when both oxidation and reduction have occurred in the same reaction.

Question 12

What are three things you can say to summarise the reaction of halogens and hallide ions?

Answer 12

1. Reactivity decreases down the group.
2. The strongest oxidising agent is fluorine.
3. A halogen displaces a less reactive halogen.

Question 13

How can you make it easier to distinguish the difference between the silver hallide percipitates instead of just looking at colours?

Answer 13

Add ammonia solution and look at the solubility of the percipitates. Silver chloride is most soluble in ammonia.
Silver chloride > silver bromide > silver iodide