group 17

Boiling point trend

increase down the group

increasing # of e- = stronger Van Der waals

En trend

Decreases going down the group

atomic radius increase = outer shell further from nucleus = more shielding = less attraction to other e-

reactivity trend

decreases going down the group

increasing atomic radius = less attraction to other e-

oxidizing power trend

gets weaker down the group

increasing shielding + atomic radius + less attraction for other e-

oxidizing power rules

INES oxidize the IDES

Chlorine oxidizes Iodide ions to iodine

Can’t oxidize anything above it

reaction with hydrogen product

hydrogen halides

reactions with hydrogen explosive trend

Less explosive going down the group

rxns with hydrogen thermal stability trend

less thermally stable down the group

small size + high en = stronger bond

length of bond increases down the group = longer bond = weaker bond

disproportionate chlorine in cold alkaline reaction

Cl2 + 2NaOH → NaCl + NaClO + H2O

disproportionate chlorine in hot alkaline

3Cl2 + 6NaOH → 5NaCl + NaClO3 + 3H2O

chlorine oxidation number in cold alkaline disproportionation

before rxn: 0

after rxn: +1, -1

chlorine oxidation numbers in disproportionation reaction hot alkali

before: 0

after: -1 +5

color of chlorine precipitate wheen silver nitrate is added

white

color of bromide precipitate when silver nitrate is added

cream

color of iodide precipitate when silver nitrate is added

pale yellow

testing for halide - does chloride precipitate dissolve with dilute ammonia

yes

testing for halide - does bromide precipitate dissolve with dilute ammonia

no

testing for halide - does iodide precipitate dissolve with dilute ammonia

no

testing for halide - does chloride precipitate dissolve with concentrated ammonia

yes

testing for halide - does bromide precipitate dissolve with concentrated ammonia

yes

testing for halide - does iodide precipitate dissolve with concentrated ammonia

no

observations of Cl with sulfuric acid

HCl produce white fumes

Br observations w sulfuric acid

HBr - white fumes

Br2 - reddish brown gas

observations of Iodide & sulfuric acid

Sulfur- yellow solid

Hydrogen selfie H2S - strong smell of bad eggs

Iodine, I2 - violet/purple vapor

reducing power trend

gets stronger down the group