Topic 11 - Halogens

Question 1

Describe the atomic arrangement of halogens

Answer 1

They are all diatomic

Question 2

What is the difference between a halogen and a halide

Answer 2

Halogen - molecule (eg. Cl)

Halide - ion (eg. Cl-)

Question 3

Describe fluorine

Answer 3

• Gas
• Pale yellow in pure form
• Cannot exist in aqueous solutions
• colourless in organic solutions

Question 4

Describe chlorine

Answer 4

• gas
• pale green in pure form
• cannot exist in aqueous solution
• pale green in organic solution
• poisonous
• fairly reactive
• BP -34°C

Question 5

Describe bromine

Answer 5

• liquid
• red-brown in pure form
• yellow-orange in an aqueous solution
• red in an organic solution
• gives off an orange vapour at room temperature
• BP = 59°C

Question 6

Describe iodine

Answer 6

• crystalline solid
• dark grey in pure form
• brown in aqueous solution
• purple in organic solution
• gives off a purple vapour when heated
• BP = 185°C

Question 7

Describe astatine

Answer 7

• solid
• black in pure form
• there is not enough to dissolve it
• MP = 300°C

Question 8

Describe and explain the reactivity trend of halogens

Answer 8

They get less reactive as the group descends

Because there is a greater distance between protons and the electrons it’s trying to gain in elements such as iodine and astatine compared to fluorine and chlorine- therefore the attraction is weaker and it’s harder to get the extra electron to fill the outer-shell

Question 9

describe hydrogen chloride

Answer 9

Colourless gas

Question 10

Describe what happens to hydrogen chloride solutions in water

Answer 10

They dissociate , therefore it can conduct electricity

Does not dissociate in methylbenzene , therefore it cannot conduct