3.1.3 the halogens Flashcards
what type of molecules do halogens exist as
diatomic molecules
eg-cl2, br2
why are halogens p block elements
as there highest energy electron is in the p subshell
what is the trend in boiling points down group 7
boiling points increase down the group
-more electrons
-stronger London forces
-requires more energy to overcome
what is the trend in volatility down group 7
decreases
-more electrons
-strength of London forces increases
-more energy is required to overcome this attraction
what is the trend in reactivity down group 7
decreases as it becomes more difficult to form a 1- ion
-atomic radius increases
-electron sheilding increases
-nuclear attraction decreases
what happens in a redox reaction of group 7
more reactive halogen displaces a less reactive halogen from an aqueous solution of its halide ions
what colour is chlorine dissolved in water
pale yellow
what colour is chlorine dissolved in organic solvent
yellow
what colour is bromine dissolved in water
orange
what colour is bromine dissolved in organic solvent
orange-red
what colour is iodine dissolved in water
brown
what colour is iodine dissolved in organic solvent
purple
what do you have to dissolve the halide ions in so that the colours are more vibrant
organic solvent
eg-cyclohexane
what is disproportionation
NOTE THE SPELLING
where the same element is oxidised and reduced
write an equation for the disproportion of chlorine with dilute NaOH to form bleach and conditions
2NaOH + Cl2 -> NaClO + NaCl + H2o
15 degrees Celsius
