1. What is causing this girl to rub her eyes?
Group 7 elements
Quick Starter
What is causing this girl to rub her eyes?
show hint
show answer

2. But it turns out that the truth is far more disgusting
Group 7 elements
Quick Starter
People often think that chlorine – which is added to swimming pools to kill bacteria – can irritate people’s eyes
But it turns out that the truth is far more disgusting
A 2015 report from the Centers for Disease Control and Prevention (CDC) suggests that it’s urine that makes your eyes itch!
The CDC’s Dr Michael Beach said: "Chlorine binds with all the things it's trying to kill from your bodies, and it forms these chemical irritants; that's what's stinging your eyes – it's the chlorine binding to the urine and sweat"
back to question

3. Learning questions: What are the halogens?
Where are they found in the periodic table?
What trends are there in the halogens?
What kind of reaction do the halogens undertake?
Why do halogens react they way they do?
Keywords:
Group 7, halogens, oxidation, reduction, shielding, electrons, density, trend, electronic structure, displacement reaction, reactivity, diatomic.

4. What are the halogens? NK
The halogens are another name for the group 7 elements.
Why are they all in the same group?
What does this tell you about their electronic structure?
Keywords:
Group 7, halogens, oxidation, reduction, shielding, electrons, density, trend, electronic structure, displacement reaction, reactivity, diatomic.

5. Task - Electronic structure
Draw out the electronic structure of the halogens chlorine and fluorine.
What do they need to do to get a full outer shell?
What charge would their ion have?
Could their structure affect their properties? Why?
Remember!
2 electrons on the inner shell, followed by a maximum of 8 in the next.

6. Diatomic molecules
•Halogens are diatomic (go round in pairs). They do this to make sure each atom has a full outer shell of electrons.
•How does each of them join so they both have a full outer shell?

7. Spot the trend. What happens next?CM
Spot the trend. What happens next?
Atomic Number
Relative Atomic Mass
Boiling Point(0C)
Melting Point(0C)
fluorine (F) 9
19.99
-188
-220
chlorine (Cl) 17
35.45
-35
-101
bromine (Br) 35
79.90 59 -7
iodine (I) ?
Keywords:
Group 7, halogens, oxidation, reduction, shielding, electrons, density, trend, electronic structure, displacement reaction, reactivity, diatomic.

8. Spot the trend. What happens next?CM
Spot the trend. What happens next?
Atomic Number
Relative Atomic Mass
Boiling Point(0C)
Melting Point(0C)
fluorine (F) 9
19.99
-188
-220
chlorine (Cl) 17
35.45
-35
-101
bromine (Br) 35
79.90 59 -7
iodine (I) 53
126.90
184
114
Keywords:
Group 7, halogens, oxidation, reduction, shielding, electrons, density, trend, electronic structure, displacement reaction, reactivity, diatomic.

9. How do the halogens react?CM
Would you expect them to be reactive or unreactive?
Would they react with alkali metals?
Example:
Sodium + chlorine → sodium chloride
2Na + Cl2 → 2NaCl
Try writing a word and symbol equation for the reaction of bromine with sodium. What do you notice?
Keywords:
Group 7, halogens, oxidation, reduction, shielding, electrons, density, trend, electronic structure, displacement reaction, reactivity, diatomic.

10. Are they all as reactive as each other?
When halogens react they gain an electron to become a halide ion (1- charge).
Would you expect them to react at the same speed? Why?
Keywords:
Group 7, halogens, oxidation, reduction, shielding, electrons, density, trend, electronic structure, displacement reaction, reactivity, diatomic.

11. Reactivity explained Explain the order of reactivity.
Relate it to the atom’s ability to attract an electron as they all want to gain an electron.
Smaller halogens have a less shielded positive nucleus closer to their outer shell of electrons so are more able to attract an electron to that outer shell than the larger molecules as their outer shell is more shielded from the nucleus
Keywords:
Electrons, trend, electronic structure, shielding, reactivity, atomic radius, attraction, nucleus

12. Displacement reactionsCM
A more reactive halogen will displace a less reactive halide ion from its compound.
Fill in the table as you watch the video.
Which seem to react? Try and explain what is happening.
atterns/groupsrev5.shtml
Keywords:
Group 7, halogens, oxidation, reduction, shielding, electrons, density, trend, electronic structure, displacement reaction, reactivity, diatomic.

13. sodium chloride (NaCl)
Displacement reactions with halogens
chlorine water (Cl2)
bromine water (Br2)
iodine solution (I2)
sodium chloride (NaCl)
sodium bromide (NaBr)
sodium iodide (NaI)
Keywords:
Group 7, halogens, oxidation, reduction, shielding, electrons, density, trend, electronic structure, displacement reaction, reactivity, diatomic.

14. Complete word equations for the following displacement reactions
ATD
Some may not change depending on their reactivity.
Sodium chloride + fluorine→
sodium iodide + chlorine→
sodium fluoride + bromine→
Extension:
Try writing balanced symbol equations for the reactions.
Sodium chloride= NaCl, sodium iodide = NaI, fluorine =F2, Chlorine= Cl2
Keywords:
Group 7, halogens, oxidation, reduction, shielding, electrons, density, trend, electronic structure, displacement reaction, reactivity, diatomic.

15.  Identify which halogens will displace iodine from a solution of potassium iodide. Justify your answer.
 Write a balanced symbol equation for the reaction between chlorine and potassium iodide.
 Astatine is at the bottom of Group 7. It is radioactive and extremely rare so its chemistry has not been well studied.
a) Predict the state of astatine at room temperature.
b) Write a balanced equation for the reaction between chlorine and sodium astatide, NaAt.
c) Explain whether astatine, At2, will react with sodium iodide, NaI.
Keywords: Group 7, halogens, oxidation, reduction, shielding, electrons, density, trend, electronic structure, displacement reaction, reactivity, diatomic.