3.1.3 The Halogens

Question 1

What are the halogens?

Answer 1

• Group 17 on the periodic table
• most reactive non-metallic group
• appear as stable halide ions in nature not in their elemental form
• they are all diatomic

Question 2

Describe the trend in boiling points of the halogens

Answer 2

• as you go down the group the boiling points increase
• due to more electrons and stronger London forces
• therefore the intermolecular forces are stronger

Question 3

What are the states of the halogens? (at room temperature)

Answer 3

Gases: F2 and Cl2
Liquids: Br2
Solids: I2

Question 4

Describe the appearance of the halogens at room temperature

Answer 4

F2: pale yellow gas
Cl2: pale green gas
Br2: red-brown liquid
I2: shiny grey-black solid

Question 5

What is the most common reaction of the halogens?

Answer 5

Redox

Question 6

Describe the trend in reactivity of the halogens

Answer 6

• the reactivity decreases as you go down the group
• due to an increase in atomic radius
• more inner shells so increase in shielding
• less attraction to the nucleus