Halogens

Question 1

What letter often represents a halogen

Answer 1

X

Question 2

What outer shell configurations do all group 7 have

Answer 2

P5

Question 3

What state do all natural group 7 elements exists as

Answer 3

Diatomic molecules
Single cov bond

Question 4

Covalent radius trend down group 7

Answer 4

Increases
More electrons
More electron shells
Take up more space

Question 5

Ionisation energy trend going down group 7

Answer 5

Decreases
Outer electron further from nucleus
Less ESA
Easier to remove

Question 6

Electron affinity trend down group 7

Answer 6

Decreases
Expect F (lower than Cl)

Question 7

Ionic radius down group trend group 7

Answer 7

Increases

Question 8

Electronegativity trend down group 7

Answer 8

Decreases
I same as C (C-I basically non-polar)

Question 9

F2 state, appearance room temp, aqueous solutions, dissolved hydrocarbon solvent

Answer 9

Pale yellow gas
Virtuallly colourless
Virtually colourless

Question 10

Cl2 state, appearance room temp, aqueous solutions, dissolved hydrocarbon solvent

Answer 10

Green gas, virtually colourless, pale yellow

Question 11

Br2 state, appearance room temp, aqueous solutions, dissolved hydrocarbon solvent

Answer 11

Red/brown liquid, yellow, orange

Question 12

I2 state, appearance room temp, aqueous solutions, dissolved hydrocarbon solvent

Answer 12

Grey metal looking solid, orange/brown, purple

Question 13

Group 7 solubility

Answer 13

Non-polar molecules
High solubility in no-polar solvents
Limited solubility in water

Question 14

Bubble Cl2 gas through water

Answer 14

Makes chlorine water
Mixture of dissolved Cl2 and disproportionation between Cl2 and H2O

Question 15

NaHOCl (aq)

Answer 15

Bleach

Question 16

Why do halogens dissolve in hydrocarbon solvent and what colour do they take on

Answer 16

Both non-polar molecules
Cl- green/yellow
Br- brown/orange
I- purple

Question 17

How does iodine dissolve in water

Answer 17

In a KI solution
I2(s) + I-(aq) —> I3-(aq)

Question 18

What do all halogens act as and then become

Answer 18

Oxidising agents
Become halides

Question 19

Oxidisation power trend group 7

Answer 19

Decreases down group

Question 20

What do all halide ions act as and then become

Answer 20

Reducing agents
Halogens

Question 21

Reducing power trend group 7

Answer 21

Increases down group

Question 22

Describe a test for halide ions

Answer 22

Nitric acid (remove carbonate ions, misleading white ppte)
Silver nitrate form..
White ppte - chloride
Cream ppte - bromide
Yellow ppte - iodide

Question 23

Another test for halide ions

Answer 23

Add dilute ammonia solution
Cl- dissolves
Add conc ammonia solution
Br- dissolves
I- never dissolves

Question 24

Litmus hydrogen halide test

Answer 24

Turn damp blue litmus red

Question 25

How do halogens react with ammonia gas

Answer 25

Make ammonium halide compound Ionic solid White smoke

Question 26

Can hydrogen halides dissolve in water

Answer 26

Yes Disassociate Acidic solutions Every HCl disassociated: strong acid

Question 27

Hydronium/hydroxonium ion

Answer 27

H3O+ Shown as H+

Question 28

Potassium halide reactions with sulfuric acid

Answer 28

Chlorines KCl(s) + H2SO4(aq) —> KHSO4(s) + HCl(g) Bromines KBr(s) + H2SO4(aq) —> KHSO4(s) + HBr(g) HBr reduces S from +6 to +4 2HBr(g) = H2SO4(aq) —> Br2(g) + SO2(g) + 2H2O(l) Iodines No HI survives, reduces S from +6 to 0/-2 8HI(g) + H2SO4(aq) —> H2S(g) + 4I2(g) + 4H2O(l)

Question 29

Carbonate ion test

Answer 29

Add acid Fizzing CO2 produced Bubble through limewater colourless —> cloudy Solid or solution

Question 30

Sulfate ion test

Answer 30

HCl, react with carbonate ions that might give a false positive Add barium chloride solution White ppte

Question 31

Ammonium ions test

Answer 31

Add sodium hydroxide Gently heat Damp red litmus over gas Turns blue Ammonia is a base Makes white smoke with HCl vapour

Question 32

Halates and oxidation numbers

Answer 32

+1 ClO- (I) +3 ClO2- (III) +5 ClO3- (V) +7 ClO4- (VII)

Question 33

Halate oxidising power trend

Answer 33

Produce halogen or halide Increase ox number, increase oxidising power

Question 34

Halogens with cold aqueous hydroxide Then heated

Answer 34

Cl2 + 2OH- —> ClO- + Cl- + H2O 3ClO- —> ClO3- + 2Cl- 3Cl2 + 6OH- —> ClO3- + 5Cl- + 3H2O Disproportionation easier down group, lower temp needed