3.1.3 the halogens

down the group boiling point

increases

down the group the reactivity

decreases

-more electrons
-more London forces
-more energy required to break the intermollecular forces

boiling point increases

-atomic radius increases
-more inner shells so shielding increases
-less nuclear attraction to capture an electron from another species

reactivity decreases

group 7 outer shell

s2p5

disproportionation

oxidation and reduction of the same element

chlorine + water

chloric acid + hydrochloric acid

chlorine + water is used for

water treatment

chlorine + sodium hydroxide (dilute, aqueous, cold)

sodium chlorate + sodium chloride + water

chlorine + sodium hydroxide is used to form

bleach

halide ions + silver ions

silver halides

Cl2 (in water and cyclohexane)

pale green

Br2 (in water and cyclohexane)

orange

I2 (in water)

brown

I2 (in cyclohexane)

violet

Cl-(colour of precipitate)

white

Br-(colour of precipitate)

cream

1)add aqueous silver nitrate AgNO3 to an aqueous solution of a halide, the silver
halide precipitates are similar colours
2)add aqueous ammonia to test the solubility which can help differentiate the precipitate colour as they are similar

presence of halides

I-(colour of precipitate)

yellow