Group 7 Flashcards
name for G7
halogens
How do G7 exist
diatomic molecules: X2
What type of agent are G7
oxidizing agents as they cause another species to lose an electron
Colour or Cl2 dissolved in water or non polar solvent
pale green
Colour of Br2 in water or non polar solvent
Orange
Colour of I2 in water or non polar solvents
in water: brown
in non polar solvent: purple
How can we check he colour if G7
Dissolve halogen in water, add non polar solvent and shake. Bc halogens are non polar, they dissolve more readily in the ‘like’ solvent so colour is darker
Trend in reactivity/ oxidation ability of G7
Both decrease down the group
Explain y reactivity decreases down the group
Atomic radius increases
Inner shell shielding increases
So less nuclear attraction to gain an electron
Disproportionate reaction
when same species is both oxidized and reduced
Examples of disproportionate reactions involving Cl
Chlorine reacted with water to give chloric (I) acid and hydrochloric acid
Chlorine reacted with cold, dilute, aqueous sodium hydroxide to give sodium chlorate (I) , sodium chloride and water
What is the use of chloric acid (I)
the chlorate ions kill all bacteria present when aqueous so are used to purify water, ensuring our water is safe to drink
Use of sodium chlorate (I)
An ingredient in household bleach
Risks of using chlorine in water
Extremely toxic gas:
small conc is respiratory irritant
large conc can be fatal
Cl added to drinking water can react with organic hydrocarbons to form chlorinated hydrocarbons, a suspected carcinogen
Do benefits outweigh risks in using Cl in water
yes
