The document compares the properties of the halogens (F, Cl, Br, I, At). It shows that fluorine has the lowest boiling point and is the most reactive, while iodine has the highest boiling point and is the least reactive. Fluorine forms a yellow gas, chlorine forms a green gas, bromine forms an orange liquid, and iodine forms a grey solid. Astatine is predicted to have a higher boiling point than iodine and be less reactive. Displacement reactions are discussed, where more reactive halogens can displace less reactive ones from their compounds.

1. Group 7 – The Halogens
Boiling
Colour reactivity
point
F
Cl
Br
I
At

2. Predict the properties of F and At
Boiling
reactivity
point
F ?? ?? ??
Cl Green gas v. low More reactive
Br Orange liquid
I Grey solid higher Less reactive
At ?? ?? ??

3. The properties of F and At
Boiling
reactivity
point
Lower than The most
F Yellow gas chlorine reactive!
Cl Green gas v. low More reactive
Br Orange liquid
I Grey solid higher Less reactive
Higher than Less reactive
At Black solid iodine than iodine

4. sodium + chlorine → sodium chloride
• Watch the video below of sodium reacting
with chlorine.
• Each atom needs to get a full _______ ______
• Draw electrons in shells to show what
happens to a Na atom and a Cl atom during
this reaction.

5. sodium + chlorine → sodium chloride
• Watch the video below of sodium reacting
with chlorine.
• Each atom needs to get a full outer shell.
• Draw electrons in shells to show what
happens to a Na atom and a Cl atom during
this reaction. Chlorine rips the outer shell
electron from sodium to fill its own outer
shell.

6. When sodium reacts with chlorine...
Oxidation or reduction?
Oxidation or reduction?
Chlorine atom
Cl 2,8,7
• Click for animation

7. Ionic bonding in NaCl
Na → Na+ + e-
Oxidation Is Loss
(OIL)
Cl + e- → Cl-
Reduction Is Gain
(RIG)
Chlorine atom Chloride ion
Cl 2,8,7 Cl - [2,8,8]-
• Click for animation

8. Displacement reactions
• Watch the Animation : Cl2 + KCl / KBr / KI
• Video : displacement reactions
• Video: displacement using fluorine
• So, more reactive halogens displace less
reactive halogens from their compounds
Chlorine > Bromine > Iodine

9. Displacement reactions
• More reactive halogens displace less reactive
halogens from their compounds
F Potassium bromide + chlorine →
Cl Potassium fluoride + iodine →
Br Sodium chloride + fluorine →
I
lithium bromide + iodine →
At

10. Displacement reactions
• More reactive halogens displace less reactive
halogens from their compounds
F Potassium bromide + chlorine → potassium chloride + bromine
Cl Potassium fluoride + iodine → no reaction
Br Sodium chloride + fluorine → sodium fluoride + chlorine
I
lithium bromide + iodine → no reaction
At

11. Displacement reactions
• More reactive halogens displace less reactive
halogens from their compounds
F Potassium bromide + chlorine → potassium chloride + bromine
Cl 2KBr + Cl2 → 2KCl + Br2
Br Sodium chloride + fluorine → sodium fluoride + chlorine
I 2NaCl + F2 → 2NaF + Cl2
At

12. Halogens go round in pairs
• Full outer shell
• Outer shells overlap
• Atoms share electrons
• COVALENT BOND
• Don’t conduct electicity
• “Simple” molecules
• Low m.p./b.p.

13. Other covalent molecules
• Click for animation • Click for video