C1 - Group7 Halogens (part3)

What is the trend in reactivity of Group 7 elements as you go down the group?

Reactivity decreases

Which is the most reactive halogen?

Fluorine

Why do halogen atoms react?

To gain one electron and achieve a full outer energy level

What happens to a fluorine atom during a reaction with a metal?

It gains one electron

Why is fluorine more reactive than chlorine?

Fluorine attracts electrons more strongly due to less distance and less shielding

What does shielding mean in atomic structure?

Repulsion by electrons in inner energy levels, which reduces attraction to the nucleus

Why does shielding increase down Group 7?

Because atoms have more internal energy levels

What effect does increased shielding have on reactivity?

It decreases reactivity by weakening the attraction between the nucleus and incoming electrons

Why is it harder for iodine to gain an electron than fluorine?

Because iodine has more shielding and a larger atomic radius

What two factors reduce reactivity in halogens down the group?

Increased atomic radius and increased shielding

What is a displacement reaction in terms of halogens?

A more reactive halogen displaces a less reactive halogen from an aqueous solution of its salt

Can fluorine displace bromine from sodium bromide solution?

Yes, because fluorine is more reactive than bromine

What are the products of the reaction: sodium bromide + fluorine?

Sodium fluoride + bromine

Can chlorine displace iodine from potassium iodide solution?

Yes, because chlorine is more reactive than iodine

What are the products of the reaction: potassium iodide + chlorine?

Potassium chloride + iodine

Can bromine displace chlorine from lithium chloride solution?

No, because bromine is less reactive than chlorine

What happens if a less reactive halogen is added to a salt of a more reactive halogen?

No reaction occurs

How do you predict the outcome of a halogen displacement reaction?

Compare the reactivity of the halogens involved; the more reactive one will displace the less reactive one

What is the general rule for halogen displacement reactions?

A halogen will displace another halogen lower down the group, but not one above it

What state is the halide salt in during displacement reactions?

Aqueous (dissolved in water)

Why do halogens become less reactive down the group?

The outer electrons are further from the nucleus and experience more shielding, reducing the attraction for an incoming electron