Halogens Flashcards
What colour and state is fluorine?
Very pale yellow gas.
What colour and state is chlorine?
Pale green gas.
What colour and state is Bromine?
Brown liquid.
What colour and state is iodine?
Dark grey solid.
What colour and state is astatine?
Black solid
What is the reactivity trend of halogens?
They get less reactive down the group. All halogen atoms need to gain an electron to fill their outer shell. This happens less easily as you go down the group because:
-Atoms have more electron shells
-The extra electron is further from the nucleus
-So its attraction to the nucleus is weaker
What happens when hydrogen chloride dissolves in water compared to methylbenzene?
Water:
-HCl(g) dissolves to form HCl(aq)
-HCl(aq) dissociates to form H+(aq)
-The H+(aq) is acidic
-HCl(aq) is called hydrochloric acid
Methylbenzene:
-HCl(g) dissolves to form HCl(org)
-HCl(org) cannot dissociate
-There is no H+(org)
-HCl(org) is not acidic
What are displacement reactions like with halogens?
More reactive halogens can displace less reactive halogens from their compound.
What happens when KCl reacts with Br2?
No change (stays yellow)
What happens when KCl reacts with I2?
No change (stays brown)
What happens when KBr reacts with Cl2?
Chlorine displaces bromine (colourless to yellow)
What happens when KBr reacts with I2?
No change (stays brown)
What happens when KI reacts with Cl2?
Chlorine displaces iodine (colourless to brown)
What happens when KI reacts with Br2?
Bromine displaces iodine (yellow to brown)
