halogens 4.3 Flashcards
halogen bonds and structure
covalently bonded, simple molecular substances
trends in halogens properties
- all diatomic
-colour gets darker down the group
-MP/BP increases down the group
fluorine properties
pale yellow, gas
chlorine properties
pale green, gas
bromine properties
brown, liquid, volatile
iodine properties
dark grey, solid, sublimes
astatine properties
black, solid
what happens when halogens react with metals
form ionic compounds
what is a redox reaction
when one atom is oxidised (loses an electron) and the other is reduced (gains an electron)
halogen reactivity trend
less reactive down the group
why is it harder for halogen atoms to gain an electron to fill their outer shell as you go down the group
- atoms have more electron shells
- extra electron is further from the nucleus
- attraction to the nucleus is weaker
chemical test for chlorine
damp blue litmus turns white
why does chlorine turn blue litmus white
chlorine acts as a bleaching agent, removing the colour from the paper
how does hydrogen chloride form
when hydrogen reacts with chlorine
why is HCl a gas
low boiling point due to weak intermolecular forces
what happens when HCl is dissolved in water
hydrochloric acid is formed
what happens when HCl is dissolved in methylbenzene
HCl (org) is formed
what happens when a more reactive halogen reacts with one less reactive
the more reactive halogen displaces the less reactive on from their compound
Cl2 colour
colourless
Br2 colour
yellow
I2 colour
Brown
KCl colour
colourless
KBr colour
colourless
KI colour
colourless
KCl reacts with Br2
no change
KCl reacts with I2
no change
KBr reacts with Cl2
chlorine displaces bromine, colourless –> yellow
KBr reacts with I2
no change
KI reacts with Cl2
chlorine displaces iodine, colourless –> brown
KI reacts with Br2
bromine displaces iodine, yellow –> brown
what type of reaction are all halogen displacements
redox reactions
