Halogens

Question 1

What happens to the melting and boiling points of the halogens as you go down the group?

Answer 1

Both the melting and boiling points increase as you go down group 7

Question 2

What is the molecular structure of the halogens?

Answer 2

They are simple molecular lattices that are covalently bonded

Eg. Cl2

Question 3

What type of IMF exist between the halogens?

Answer 3

London forces (induced dipole-dipole)

Question 4

What happens to the IMF as you move down group 7?

Answer 4

They London forces increase with the number of electrons.

Stronger IMF as you go down the group hence why melting and boiling points increase.

Question 5

Are all halogens electronegative?

Answer 5

Yes all halogens are electronegative.

However the electronegativity decreases as you go down the group

Question 6

Are halogens oxidising or reduction agents?

Answer 6

The group 7 elements all act as oxidising agents as they remove an electron from other species to complete their outer shell

Question 7

What happens to reactivity in group 7?

Answer 7

Reactivity decreases as you go DOWN the group eg. F2 most reactive

Therefore fluorine is also the strongest oxidising agent

Question 8

In displacement reaction involving halogens what can we dissolve in the solution to make it easier to distinguish what has been displaced?

Answer 8

We can dissolve cyclohexane to see the colour of the halogens clearer

Iodine when it is mixed with cyclohexane = purple

Bromine when it is mixed with cyclohexane = orange

Question 9

What can we add to aqueous halogens to form precipitates?

Answer 9

We add AgNO3 (silver nitrate) to from a silver halide.

Silver chloride = white precipitate
Silver bromide = cream precipitate
Silver iodide = yellow precipitate