4.2 Group 7 Flashcards
What are the properties of group 7 elements?
diatomic
darker in colour down group
mp / bp increases down group
What are the group 7 elements?
F2
Cl2
Br2
I2
At2
What is the formula for Fluorine?
Fl2
What is the formula for Chlorine?
Cl2
What is the formula for Bromine?
Br2
What is the formula for Iodine?
I2
What is the formula for Astatine?
At2
What is the colour of Fluorine?
pale yellow
What is the colour of Bromine?
brown
What is the colour of Chlorine?
pale green
What is the colour of Iodine?
dark grey
What is the colour of Astatine?
black
What state is Fluorine?
gas
What state is Chlorine?
gas
What state is Bromine?
liquid
What state is Iodine?
solid
What state is Astatine?
solid
What happens when group 7 elements react with metals?
ionic compound forms
outer shell electrons from metal transferred to halogen
How many electrons do group 7 elements have in the outside shell?
7
What happens when the group 7 atom forms an ion?
halogen -> halIDE
Why is group 7 + metal a redox reaction?
metal loses electrons
group 7 gains electrons
Why do halogens get less reactive down the group?
need full electron shell
atoms further down have more shells
further from nucleus
attraction to nucleus is weaker
What is the chemical test for chlorine?
damp blue litmus paper turns white
When does halogen displacement occur?
more reactive halogens displace less reactive halogens
What colour is aqueous Chlorine?
colourless
What colour is aqueous Bromine?
yellow
What colour is aqueous Iodine?
brown
What colour is potassium chloride?
colourless
What colour is potassium bromide?
colourless
What colour is potassium iodide?
colourless
What is the reactivity trend in group 7?
clinton
brought
itchiness
What is the order of group 7?
for
class
bro
i
ate
What happens when colour change occurs in halogen displacements?
more reactive halogen must be present
What happens when no colour change occurs in halogen displacement?
less reactive halogen must be present
Colour change only occurs if….
more reactive halogen has displaced less reactive halogen
A halogen can not displace…
itself or a more reactive halogen
remember! the colour of the solution left behind is the colour of the…
displaced halogen NOT the more reactive halogen
Why is the colour of the solution left behind the colour of the displaced halogen?
when displaced, the halogen becomes diatomic again rather and the more reactive halogen becomes a halIDE
All halogen displacement reactions are…
redox reactions
Why are all halogen displacement reactions redox reactions?
more reactive halogen steals an electron
What does Bromine release?
releases brown fumes
What does Iodine release?
releases purple fumes
What does Bromine do?
volatiles
What does Iodine do?
sublimes
