Group 7

Question 1

What block are they in?

Answer 1

P block

Question 2

What bond is in the halogen molecule?

Answer 2

Covalent

Question 3

Diatomic?

Answer 3

Yes

Question 4

What structure do they have?

Answer 4

Simple molecular

Question 5

What happens to the colour as you go down the group?

Answer 5

Increases down the group

Question 6

What happens to volatility down the group?

Answer 6

Decreases down the group

Question 7

Are there temporary or permanent dipoles?

Answer 7

Temporary

Question 8

What happens when there is more electrons in the molecule?

Answer 8

The greater the induced dipoles and the greater the attraction between the molecules

Question 9

Fluorine and chlorine state at room temp and pressure?

Answer 9

Gas

Question 10

Bromine state at room temperature and pressure?

Answer 10

Liquid

Question 11

Iodine and astatine state at room temperature and pressure?

Answer 11

Solid

Question 12

What happens to electronegativity as you go down group 7?

Answer 12

Electronegativity decreases- elements become less electronegative.
Atomic radius increases as well as the number of protons
The outermost electron is further away from the nucleus- decreasing the nuclear attraction
More protons as well- increases the nuclear charge
Harder for the atom to attract the shared pair of electrons in a covalent bond
Shielding increases

Question 13

What electron structures do group 7 end in?

Answer 13

P5

Question 14

Are group 7 elements reduced or oxidised?

Answer 14

Reduced d

Question 15

Are group 7 elements reducing agents or oxidising agents?

Answer 15

Oxidising agents

Question 16

Br2 and Cl2?

Answer 16

Aqueous layer- stays orange
Organic layer- stays orange

Question 17

Which layer is always at the top?

Answer 17

The organic layer
The aqueous layer is always at the bottom

Question 18

What reaction is between bromine and chlorine?

Answer 18

No reaction

Question 19

I2 and Cl-?

Answer 19

Organic- brown
Aqueous- violet

Question 20

Reaction between I2 and Cl2?

Answer 20

No reaction

Question 21

Cl2 and Br-?

Answer 21

Aqueous layer goes from colourless to orange
Organic layer goes from colourless to orange

Question 22

I2 and Br-?

Answer 22

Organic layer- stays brown
Aqueous layer- stays violet

Question 23

Cl2 and I-?

Answer 23

Aqueous layer- goes from colourless to brown
Organic layer- goes from colourless to violet

Question 24

Reaction between Cl2 and I-?

Answer 24

2I + Cl2 -> I2 + 2Cl-

Question 25

Br2 and I-?

Answer 25

Aqueous layer goes from orange to brown Organic layer goes from orange to violet

Question 26

Reaction between bromine and I-?

Answer 26

Br2 + 2I- -> I2 + 2Br

Question 27

Trend in reactivity down group 7?

Answer 27

They get less reactive

Question 28

What is the strongest oxidising agent?

Answer 28

Chlorine (strongest) Bromine (middle) Iodine (weakest

Question 29

Why does electron affinity decrease down the group?

Answer 29

Atomic radius increases Shielding increases Nuclear attraction decreases so it becomes harder to gain an electron

Question 30

What type of reaction is chlorine and water?

Answer 30

Disproportionation as Cl2 is being oxidised and reduced

Question 31

What are the products formed for chlorine and water?

Answer 31

Hydrochloric acid and chloric acid

Question 32

What happens to indicator paper when chlorine water is added?

Answer 32

Indicator paper turns red due to the hydrochloric acid The colour is removed from the indicator paper due to the ClO-

Question 33

What are the advantages of sterilising water?

Answer 33

Prevents waterborne diseases (cholera)

Question 34

Why do some people think we should not use residual disinfectant systems?

Answer 34

Chlorine is toxic in excess and can react with hydrocarbons from organic substances in pipes/water to form chlorinated hydrocarbons such as chloroform- some of which are carcinogens

Question 36

CL- with silver nitrate?

Answer 36

White ppt

Question 37

Br- with silver nitrate?

Answer 37

Cream ppt

Question 38

I- with silver nitrate?

Answer 38

Yellow ppt

Question 39

Cl- with dilute ammonia?

Answer 39

Ppt disappears

Question 40

Br- with dilute ammonia?

Answer 40

No change

Question 41

I- with dilute ammonia?

Answer 41

No change

Question 42

Cl- with concentrated ammonia?

Answer 42

Ppt disappears

Question 43

Br- with concentrated ammonia?

Answer 43

Ppt disappears

Question 44

I- with concentrated ammonia?

Answer 44

No change

Question 45

What increases as you go down the group?

Answer 45

Reducing ability Atomic radius Boiling points

Question 46

What decreases as you go down the group?

Answer 46

Electronegativity Oxidising ability

Question 47

What happens to the oxidising power of the halogens as you go down the group?

Answer 47

Oxidising power decreases

Question 48

What happens to the reducing power of the halide ions as you go down the group?

Answer 48

Increases