2.2 - Group 7

Question 1

What are the group 7 elements

Answer 1

The elements in group 7 are known as the halogens.
These are fluorine, chlorine, bromine, iodine and astatine

Question 2

What are the halogens

Answer 2

These elements are non-metals that are poisonousreact with metals to form salts

Question 3

What is the reactivity like for halogens

Answer 3

All halogens have similar reactions as they each have seven electrons in their outermost shell

Question 4

What colour is Florine at room temp

Answer 4

Yellow gas

Question 5

What colour is Chlorine at room temp

Answer 5

yellow gas

Question 6

What colour is Bromine at room temp

Answer 6

Red - brown liquid

Question 7

What colour is iodine at rt

Answer 7

purple black solid

Question 8

What are the characteristic of fluorine gas

Answer 8

Very reactive poisonous gas

Question 9

What are the characteristic of Chlorine gas

Answer 9

Reactive poisonous and dense gas

Question 10

What are the characteristic of Bromine liquid

Answer 10

Dense red - brown volatile liquid

Question 11

What are the characteristic of iodine solid

Answer 11

Shimmery crystalline solid sublimes to form a purple vapour

Question 12

What is the melting and boiling point trend in the halogens

Answer 12

The melting and boiling points of the halogens increase as you go down the group
This is due to increasing intermolecular forces as the atoms become larger, so more energy is required to overcome these forces

Question 13

What is the trend for colours in the halogens

Answer 13

The colours of the halogens also change as you descend the group - they become darker

Question 14

What is the trend for reactivity in the halogens

Answer 14

The halogens decrease in reactivity moving down the group, but they still form halide salts with some metals including iron
The rate of reaction is slower for halogens which are further down the group such as bromine and iodine

Question 15

What is a displacement reaction?

Answer 15

A halogen displacement reaction occurs when a more reactive halogen displaces a less reactive halogen from an aqueous solution of its halide

Question 16

What happens when you add chlorine solution to a colourless potassium bromide

Answer 16

The solution becomes orange as bromine is formed or
The solution becomes brown as iodine is formed
Chlorine is above bromine and iodine in group 7 so it is more reactive
Chlorine will displace bromine or iodine from an aqueous solution of the metal halide:

Question 17

What is a spectator ion

Answer 17

The metal ion in a halogen reaction does not do anything doesn’t react.

Question 18

Explain the reactivity of the halogens

Answer 18

Reactivity of group 7 non-metals decreases as you go down the group
As you go down group 7, the number of shells of electrons increases, the same as with all other groups
Halogensform negative ions
This means that the increased distance from the outer shell to the nucleus as you go down a group makes the halogens become less reactiveless atraction between the nucleus and the shells
Fluorine is the smallest halogen, which means its outermost shell is the closest to the positive nucleus of all the halogen
Therefore, the ability to attract an electron is strongest in fluorine making it the most reactive
As you move down the group, the forces of attraction between the nucleus and the outermost shell decreases
This makes it harder for the atoms to gain electrons as you descend the group
Therefore, the halogens are less reactive the further down the group you go

Question 19

What are redox reactions?

Answer 19

When oxidation and reduction occours

Question 20

What happens in a displacement reaction in terms of oxidation and reduction?

Answer 20

the more reactive element acts as the oxidising agent it takes electrons away from the less reactive element reducing itself