Group 7 - 4.2

Question 1

What are the trends in the group seven properties?

Answer 1

• all diatomic
• colours get darker down the group
• MP/BP increases down the group

Question 2

What elements are in group seven and what colour and state are they?

Answer 2

Flourine - very pale yellow - gas
Chlorine - pale green - gas
Bromine - brown - liquid
Iodine - dark grey - solid
Astatine - black - solid

Question 3

What happens when they react with metals?

Answer 3

Halogens form ionic compounds

Question 4

What happens to the reactivity as we go down the group?

Answer 4

Halogens get less reactive

Question 5

Why do halogens get less reactive as you go down the group?

Answer 5

All halogen atoms need to gain an electron to fill their outer-shell - happens less easily as you go down because:
* Atoms have more electron shells
* The extra electron is further from the nucleus
* So its attraction to the nucleus is weaker

Question 6

What is the chemical test for chlorine?

Answer 6

damp blue litmus paper –> turns white

This is because the chlorine acts as a bleaching agent, so it removes the colour from the paper

Question 7

What colour is chlorine in a displacement reaction?

Answer 7

Colourless

Question 8

What colour is bromine in a displacement reaction?

Answer 8

yellow

Question 9

What colour is iodine in a displacement reaction?

Answer 9

brown

Question 10

What colour is KCl in a displacement reaction?

Answer 10

colourless

Question 11

What colour is KBr in a displacement reaction?

Answer 11

colourless

Question 12

What colour is Kl in a displacement reaction?

Answer 12

colourless

Question 13

What are all halogen displacement reactions?

Answer 13

Redox reactions