Topic 4

Question 1

Group 2 elements the ionisation energy

Answer 1

Decreases down the group new space
Each element down group 2 has an extra electron shell. this extra electron shell Shields the outer electrons from the attraction of the nucleus.
The extra shell means that the outer electrons are further away from the nucleus which reduces the electrostatic attraction between the nucleus and the outer electrons
both of the factors make it easy to remove outer electrons meaning the ionisation energy decreases down the group

Question 2

Group 2 elements reactwith water to produce

Answer 2

Hydroxide and hydrogen gas

Question 3

They burned in oxygen to form

Answer 3

Oxides

Question 4

They reacts with chlorine to form

Answer 4

Chlorides

Question 5

The oxides and hydroxides are bases

Answer 5

Oxides of group to metals react readily with water to form metal hydroxide which dissolve the hydroxide ions making the solution strongly alkaline.
Beryllium oxide is an exception as it doesn’t react with water and beryllium hydroxide is insoluble

Question 6

Singerly charge negative ions

Answer 6

Increases solubility down the group

Question 7

Doubly charged negative ions

Answer 7

Decreases solubility down the group

Question 8

Group 2 hydroxide solubility pattern

Answer 8

Increases down the group

Question 9

Group 2 sulphate solubility pattern

Answer 9

Decreases down the group

Question 10

Thermal stability…

Answer 10

Increases down the group
Large cat ions cause less distortion because they have a lower charge density and therefore polarise less. The less distortion there is, the more stable the molecule and therefore the more thermally stable it is

Question 11

Group 2 ions are… Thermally stable than group 1 ions

Answer 11

Less

This is due to group 1 ions having a +1 charge on the cation. this means less distortion and therefore it’s more stable

Question 12

Halogens are

Answer 12

Highly reactive nonmetals

Question 13

Halogens get… Reactive down a group

Answer 13

Less reactive

Question 14

Melting and boiling points…

Answer 14

Increased down the group

Question 15

Halogens can… Halide ions from solutions

Answer 15

Displace

Question 16

Halogens can react with group 1 and group 2 metals

Answer 16

When halogens react they are reduced and they oxidise other substances
They oxidise group 1 and group to metals to produce halide salts

Question 17

Halogens under go disproportionation with a cold alkali

Answer 17

In his reactions to halogen is simultaneously oxidised and reduced

Question 18

Formula for halogens reacting with cold alkalis

Answer 18

X2 + 2NaOH —> NaOX + NaX + H2O

Question 19

Bleach

Answer 19

Chlorine and sodium hydroxide (cold alkali)

Question 20

Halogens undergo disproportionation with hot alkalis

Answer 20

Halogens are oxidised to a higher oxidation number

3X2 + 6NaOH —> NaXO3 + 5NaX + 3H2O

Question 21

Chlorine is used to kill bacteria in water

Answer 21

You end up with a mixture of hydrochloric acid and hypochlorous acid
Hypochlorous acid ionises to make chlorate ions also known as hypochlorous ions
These hypochlorous ions kill bacteria

Question 22

Reducing power of halide…

Answer 22

Increases down the group
The further down the group you go, the larger the ion, so therefore the electrons are further away from the nucleus and more electrons shielding occurs
This makes it easier for an electron to be removed from its outer shell

Question 23

Reaction of KF with H2SO4

Answer 23

KF + H2SO4 —> KHSO4 + HF + misty fumes
Fluorine ions aren’t strong enough to be reducing agents
The oxidation numbers of the halide and sulphur ions stay the same as it is not a redox reaction

Question 24

Reaction of KBr with H2SO4

Answer 24

KBr + H2SO4 —> KHSO4 + HBr + misty fumes

2HBr + H2SO4 —> Br2 + SO2 + 2H2O

Question 25

Reaction of KI with H2SO4

Answer 25

KI + H2SO4 —> KHSO4 + HI
2HI + H2SO4 —> I2 + 2H2O + SO2
6HI + SO2 —> H2S + 3I2 + 2H2O

Question 26

Silver ions react with halide ions to form a precipitate

Answer 26

First add dilute nitric acid to remove ions which might interfere with the reaction
Then add silver nitrate solution (AgNO3)
A precipitate of silver halide forms

Question 27

Fluorine and silver nitrate

Answer 27

Fluorine has no precipitate as silver fluoride is insoluble so will dissolve

Question 28

To test for carbonates

Answer 28

Add HCL

Question 29

To test for sulphates

Answer 29

Add dilute HCL followed by barium chloride solution BaCl2

If a white precipitative barium sulphate is formed it means the original compound contains a sulphate