halogens Flashcards
formula for fluorine, chlorine, bromine, iodine and astatine
F2, Cl2, Br2, I2, At2
the following trends in properties of halogens?
- All are diatomic
- Colours get darker down the group
- MP/BP increases down the group
- reactivity decreases down the group
fluorine colour
very pale yellow
chlorine colour
pale green
astatine colour
black
bromine colour
brown
iodine colour
dark grey
what state is bromine
liquid
what state is fluorine and chlorine
gas
what is state is iodine and astatine
solid
other properties of iodine
Sublimes, releases purple fumes
other properties of bromine
Volatile, releases brown fumes
what happens when halogens react with metals
halogens form ionic compound
how many electrons are needed to fill halogen outer shell
one
why do halogens get less reactive going down the group
- Atoms have more electron shells
- The extra electron is further from the nucleus
- So its attraction to the nucleus is weaker
colours of aqueous halogens
Cl2(aq) = Colourles
Br2(aq) = Yellow
I2(aq) = Brown
= chlorine, bromine, iodine
colours of salt halogens
KCl(aq) = Colourless
KBr(aq) = Colourles
KI(aq) = Colourless
= chloride, bromide and iodide
what happens in the reactions between the aqueous halogens and salts
Chlorine always displaces bromine and bromine displaces iodine
Therefore reactivity:
1st chlorine
2nd bromine
3rd iodine
why are halogen displacement reactions redox reactions
The more reactive halogen atom steals an electron from the halide ion in the salt
