2.5: Know the Colours, Physical States (At Room Temperature) and Trends in Physical Properties of these Elements

HALOGENS: Group 7 Non-Metals that are poisonous and commonly include Chlorine, Bromine and Iodine

s

COLOURS AND STATES AT ROOM TEMPERATURE:

s

HALOGEN	PHYSICAL STATE AT ROOM TEMPERATURE	COLOUR
CHLORINE	Gas	Pale Green
BROMINE	Liquid	Red-Brown (readily evaporates to form a Brown Gas)
IODINE	Solid	Black (sublimes to form a Purple Gas)

s

TRENDS IN PHYSICAL PROPERTIES:

ss

1. MELTING POINT

s

• Melting and Boiling Points of Halogens increases as you go down the Group

        

Melting and Boiling Points of Halogens

s

2. STATE AT ROOM TEMPERATURE

ss

• At room temperature (20C℃), the physical state of Halogens become harder and more set as you go down the Group
• Chlorine is a Gas, Bromine is a Liquid and Iodine is a Solid

States of Halogens

s

3. COLOUR

ss

• Halogens become darker as you go down the Group
• Chlorine is Pale Green, Bromine is Red-Brown and Iodine is Black

Colours of Halogens