2. Trends in chemical reactivity of halogens

Question 1

Summarise the properties of halogens (8)

Answer 1

1. The halogens are the most electronegative elements in the periodic table.
2. The electronegativity values decrease down the group.
3. The halogens have such a great attraction for electrons, they are quite reactive.
4. They do not exist in nature.
5. Fluorine is the most reactive of all the halogens because of its high electronegativity.
6. The trend in reactivity of the halogens is in the opposite direction to that of the alkali metals. (bottom to top)
7. The halogens tend to remove electrons easily from other substances because of their high electronegativity. A substance that removes electrons from other substances is called an oxidising agent.
8. If chlorine gas is bubbled through a solution containing bromide ions, the chlorine takes electrons from the bromide ions, converting them into bromine.

Question 2

What is the trend of electronegativity down the group of halogens?

Answer 2

The electronegativity values decrease down the group.

Question 3

Why are the halogens quite reactive?

Answer 3

The halogens have such a great attraction for electrons, they are quite reactive.

Question 4

How do the halogens exist in nature?

Answer 4

They do not exist in nature.

Question 5

What is the most reactive halogen and why?

Answer 5

Fluorine is the most reactive of all the halogens because of its high electronegativity.

Question 6

In what direction is the trend of reactivity for the halogens?

Answer 6

The trend in reactivity of the halogens is in the opposite direction to that of the alkali metals. (bottom to top)

Question 7

What is an oxidising agent?

Answer 7

A substance that removes electrons from other substances is called an oxidising agent.

Question 8

Why do the halogens tend to remove electrons easily?

Answer 8

The halogens tend to remove electrons easily from other substances because of their high electronegativity.

Question 9

What happens when chlorine gas is bubbled through a solution containing bromide ions?

Answer 9

If chlorine gas is bubbled through a solution containing bromide ions, the chlorine takes electrons from the bromide ions, converting them into bromine

Question 10

What happens when two halogens are reacting together?

Answer 10

The more reactive halogen displaces the less reactive halogen from the solution of its ions.