Group 2, The Alkaline Earth Metals 3.2.2

Question 1

In group 2, the elements are Be Mg Ca Sr and Ba
Which ones are metals in their solid stage and what type of bonding is present

Answer 1

Mg -> Ba
Metallic bonding

Question 2

Describe the trend in atom radius going down group 2

Answer 2

Atomic radius increases as there are more shells of electrons making the atom bigger

Question 3

Describe the trend in first ionisation energy going down Group 2

Answer 3

Decreases as electrons further from nucleus and outer electrons are more shielded from the nucleus, weaker attraction between nucleus and outer electron so less energy required to remove an electron

Question 4

Describe the trend in melting point going down Group 2, what is the anomaly

Answer 4

Decreases
Delocalised electrons are further from the nucleus, more sheilding, less attraction between metal ions and delocalosed electrons
Anomaly is magnesium

Question 5

Explain the reactivity going down Group 2

Answer 5

Increases as there is more shelding so weaker force of attraction between the nucleus and outer electrons so easier to lose electrons to form X²+ ions

Question 6

What does the reaction of Group 2 Alkaline metals reacting with water depend on

Answer 6

It depends on how easily electrons are lost

Question 7

What is the general equation for Group 2 Alkaline metals reacting with cold water

Answer 7

X + 2H2O -> X(OH)2 + H2

Question 8

What is the general equation for Group 2 Alkaline metals reacting with steam

Answer 8

X + H2O -> XO + H2

Question 9

Describe how Magnesium, calcium strontium and barium react with cold water

Answer 9

Magnesium Reacts very slowly with cold water
Calcium Reacts steadily with cold water
Strontium and Barium react vigorously with cold water

Question 10

How does magnesium react with cold water compared to steam

Answer 10

Magnesium Reacts very slowly with cold water but quickly with steam

Question 11

When reacting Group 2 metals with water, hydroxide are produced which make the water…. and the pH is…

Answer 11

Alkaline
pH of 10

Question 12

What are the observation changes when you react Group 2 metals with water, going down

Answer 12

-Fizzing (more vigorous down group)
-Metal dissolving (faster down group)
-Solution heating up (more down group - exothermic reaction)
-With magnesium and calcium, a white precipitate appears (less precipitate forms down group with other metals)

Question 13

When group 2 Alkaline metals reacting with water, where does oxidation and reduction occur

Answer 13

Metal is oxidised and loses two electrons
Each Hydrogen in water is reduced and gains an electron each

Question 14

As you go down group 2 what happens to the solubility of hydroxides

Answer 14

Solubility increases (magnesium and calcium only forms a precipitate)

Question 15

As you go down group 2, what happens to the solubility of sulphates

Answer 15

Solubility decreases

Question 16

What is the test for sulphates

Answer 16

Add hcl
Add barium chloride
Sulfates form a white precipitate

Question 17

Why is titanium a useful metal

Answer 17

Abundant
Low density
Corrosion resistant

Question 18

Give a use for titanium

Answer 18

Used for making strong, light alloys to use in aircarfts

Question 19

Why can’t titanium be extracted with carbon or electrolysed

Answer 19

Carbon- titanium carbide is formed rather than titanium
Titanium can’t be electrolysed because it has to be very pure

Question 20

Which group 2 metal is used to extract titanium

Answer 20

Magensium

Question 21

What steps are involved in the extraction of titanium

Answer 21

-Solid is converted into chloride (liquid state)
-Chloride is purified by Fractional distillation in an Argon atmosphere and then is reduced by magnesium

Question 22

Why is titanium expensive

Answer 22

Magnesium and Argon are expensive
Batch processes
High temperatures required in both steps

Question 23

What is the use of magnesium hydroxide

Answer 23

In medicine to alleviate constipation and also used in indigestion remedies

Question 24

What is the use of calcium hydroxide

Answer 24

In agriculture to neutralise acidic soil

Question 25

If sulfur is present in coal and crude oil, what happens when it burns

Answer 25

It produces sulfur dioxide which dissolves in moisture to form acid rain

Question 26

How can you prevent the formation of sulfur dioxide gas

Answer 26

Can be removed from power station chimneys by reacting with calcium oxide

Question 27

What is the use of barium

Answer 27

Diagnose problems with the the digestive system

Question 28

Barium 2+ ions are toxic but why is this technique harmless

Answer 28

They are Insoluble so won't pass into the bloodstream

Question 29

What are the 3 stages in chlorination of alkanes

Answer 29

Initiation Propagation Termination

Question 30

What needs to be present when an alkane Reacts with a halogen

Answer 30

UV light

Question 31

Explain initiation in chlorination of alkanes

Answer 31

-Chlorine moelciles gain energy from UV light tk break the Cl-Cl covalent bond symmetrically -Each chlorine atom takes one electron from the shared pair of electrons and two chlorine radical atoms are formed

Question 32

What is homolytic fission

Answer 32

The breaking of a covalent bond to form two free radicals

Question 33

What is the link between intensity of UV light and rate of reaction

Answer 33

As intensity of UV light increases, rate of reaction increases as more free radicals would be produced

Question 34

What is a free radical

Answer 34

An atom with an unpaired electron