3.1.3 Group 7 Halogens

Question 1

Trend in atomic radius of halogens going down

Answer 1

-The number of electron shells increase
-So electron shielding increases
-So the attraction to the outer electron decreases
-So the atomic radius increases

Question 2

Trend in electronegativity as you go down the halogens

Answer 2

-The electronegativity decreases
-there is more shells
-more sheilding
-less attraction to the covalently bonded pair of electrons

Question 3

Trend in melting/boiling point as you go down the halogens

Answer 3

-boiling point increases
-size of molecule increases
-stronger London forces
-more required energy to break the bonds

Question 4

Colour of fluorine as a gas

Answer 4

Yellow

Question 5

What colour is chlorine as gas

Answer 5

Green

Question 6

What colour is bromine as a gas

Answer 6

Brown

Question 7

What colour is iodine as a gas

Answer 7

Purple

Question 8

Chlorine with bromide (ionic equation and colour change)

Answer 8

Cl2+2Br- —> Br2+Cl-
Colourless to pale yellow

Question 9

Chlorine + iodide (ionic equation and colour change)

Answer 9

Cl2+2I- —> I2+2Cl-
Colourless to pale brown

Question 10

Bromine + iodide (ionic equation and colour change)

Answer 10

Br2 + 2I- —> 2Br- + I2
Pale yellow to pale brown

Question 11

Which halogens and halides do not react (stay colourless)

Answer 11

Chloride + bromine/iodine
Bromide + iodine

Question 12

Reaction of water with chlorine

Answer 12

Cl2(g) + H20(l) —> HClO(aq) + HCl(aq)
Hypochlorite acid

Question 13

Reaction of chlorine and water (sunlight)

Answer 13

2Cl2(g) + 2H20(l) —> 4HCl(aq) + O2(g)
Pale green. Colourless

Question 14

What are colours do chloride, bromide and iodide go when mixed with silver nitrate

Answer 14

White -> white cream -> cream

Question 15

what is the further test for chloride, bromide and iodide (the halides)

Answer 15

-Chloride dissolves in dilute ammonia
-bromide dissolves in conc ammonia
-iodide does not dissolve in either