Group 2 & 7

Question 1

Which type of bonding is in two non-metals?

Answer 1

Covalent

Question 2

What type of bonding is in the halogens?

Answer 2

Covalent

Question 3

What are diatomic molecules?

Answer 3

Molecules which exist/go around in pairs

Question 4

Why are group 7 elements in the p block?

Answer 4

Their outermost electron lies in the p energy level

Question 5

Give the physical state of Fl2?

Answer 5

Yellow gas

Question 6

Give the physical state of Cl2?

Answer 6

Yellow/green gas

Question 7

Give the physical state of Br2?

Answer 7

Red/brown liquid

Question 8

Give the physical state of I2?

Answer 8

Grey/black solid

Question 9

What structure does a Cl2 atom have?

Answer 9

Simple covalent

Question 10

What is a covalent bond?

Answer 10

Sharing of a pair of electrons

Question 11

Does boiling point increase/decrease down the group? Why?

Answer 11

Increases

Strength of intermolecular bonds increases from more electrons and protons in molecule so more difficult to break

Question 12

Does the colour intensity increase or decrease in halogens down the group?

Answer 12

Increases

Question 13

Why do halogens act as oxidising agents?

Answer 13

It wants to gain a full outer shell so it oxidises something else and reduces itself to do this

Question 14

Which halogen is most electronegative? Why?

Answer 14

Fluorine

It has the least shielding effect and the strongest attraction meaning it is most electronegative

Question 15

State the trend in oxidising power down group 7

Answer 15

Decreases down the group as it becomes less electronegative down the group

Question 16

Why are halogens less reactive down the group?

Answer 16

It becomes harder to pull electrons into outermost shell due to attraction between nucleus and electrons dropping off with shielding effect

Question 17

When chlorine is added to potassium iodide, what happens in terms of redox?

Answer 17

Chlorine is more reactive than iodine so it will oxidise the ions of the elements below it in the periodic table and with therefore swap places with the iodine atom
Cl2 + 2KI —> 2KCl + I2

Question 18

What is the colour of the displaced halogen chlorine when dissolved in organic solution?

Answer 18

Pale yellow

Question 19

What is the colour of the displaced halogen bromine when dissolved in organic solution?

Answer 19

Orange/red

Question 20

What is the colour of the displaced halogen iodine when dissolved in organic solution?

Answer 20

Purple

Question 21

Are halogens more reactive down or up the group?

Answer 21

Up the group

Question 22

What is a displacement reaction?

Answer 22

A reaction whereby a more reactive element displaces a less reactive element

Question 23

What is a disproportionation reaction?

Answer 23

When the same element is both oxidised and reduced

Question 24

When adding aqueous silver nitrate to chlorine, bromine and iodine what is seen for each element?

Answer 24

Chlorine - white precipitate
Bromine - cream precipitate
Iodine - yellow precipitate

Question 25

If dilute aqueous ammonia is added to a mixture of halogen and aqueous silver nitrate, what would be observed?

Answer 25

Precipitate dissolves

Question 26

Give the ionic equation for chloride ions and with aqueous silver nitrates, including state symbols

Answer 26

Ag+(aq) + Cl-(aq) —> AgCl(s)

Question 27

Give an advantage of chlorine as water treatment

Answer 27

Kills bacteria

Disinfects

Question 28

Give a disadvantage for chlorine as water treatment

Answer 28

Toxic

Question 29

Give the equation for the reaction of chlorine reacting with sodium hydroxide to form bleach

Answer 29

Cl2 + 2NaOH —> NaCl + NaOCl + H2O

Question 30

Why do the halogens have different states at rtp?

Answer 30

Number of electrons increases down the shell
More London forces between these molecules
Forces greater in I2 than Br2 and greater in Br2 than Cl2

Question 31

What is meant by the term mole?

Answer 31

Amount of substance that has the same number of particles as there are in 12g of carbon-12