Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ALEVEL - Inorganic Chemistry > Group 2, The Alkaline Earth Metals > Flashcards

Group 2, The Alkaline Earth Metals Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

What compounds can group two metals form

A

All Group 2 metals can form ionic compounds in which they donate these two outermost electrons (so they act as reducing agents) to become an ion with +2 charge (so they themselves become oxidised)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What happens to group 2 reactivity further down the group

A

the metals become more reactive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is first ionisation energy

A

The first ionisation energy is the energy needed to remove the first outer electron of an atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is second ionisation energy

A

The second ionisation energy is the energy needed to remove the second outer electron of an atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why does ionisation energy decrease as we go down the group

A

Though the nuclear charge increases going down the group (because there are more protons), factors such as an increased shielding effect and a larger distance between the outermost electrons and nucleus outweigh the attraction of the higher nuclear charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

This ionisation energy trend is shown by looking at reactions of the Group 2 metals:

A

With dilute hydrochloric acid: bubbles of hydrogen gas are given off much faster indicating that the reactions become more vigorous

With oxygen: the metals get more reactive with oxygen down the group (Ba is so reactive, that it must be stored in oil to prevent it from reacting with oxygen in air)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens to the melting point as yoyu move down the group

A

The melting point of the elements decreases going down the group as the outer electrons get further away from the nucleus

This means that the attraction between the nucleus and the bonding electrons decreases causing a decrease in melting point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens to the density as we move down the group

A

the density of the alkali earth metals drops and then increases

Density is also affected by the packing structure of the metals, not just the atomic radius

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Group 2 hydroxides as we move down the group

A

the solutions formed from the reaction of group 2 oxides with water become more alkaline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

When the oxides are dissolved in water, what following ionic reaction takes place

A

O2- (aq) + H2O (l) → 2OH- (aq)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What makes the solution more alkaline

A

The higher the concentration of OH- ions formed, the more alkaline the solution

The alkalinity of the solution formed can therefore be explained by the solubility of the Group 2 hydroxides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What equation shows the hydroxides dissolve in water

A

X(OH)2 (aq) → X2+ (aq) + 2OH- (aq)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What happens to group 2 hydroxide solubility as it moves down the group?

A

Going down the group, the solubility of these hydroxides increases

This means that the concentration of OH- ions increases, increasing the pH of the solution

oing down the group, the alkalinity of the solution formed increases when Group 2 oxides react with water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How are group two hydroxides formed

A

When the metal oxides react with water, a group 2 hydroxide is formed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens to the solubility of the sulfates going down the group?

A

the solubility of the sulfates decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Uses of calcium - limestone

A

this is impure calcium carbonate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Uses of calcium - quick lime

A

this is calcium oxide, formed by the thermal decomposition of calcium carbonate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Uses of calcium - slaked lime

A

this is calcium hydroxide formed when water is added to quicklime

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How is calcium used in agriculture

A

agriculture to raise the pH of the soil

Over time, the soil becomes more acidic while the optimum pH for many crops to grow is at around 6-6.5

The compounds are all bases and react with the acids in the soil and raise the pH of the soil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Why is Calcium carbonate more commonly used in agricultural lime

A

it is cheaper and safer to handle
However, due to calcium carbonate being largely insoluble, it acts more slowly than calcium hydroxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are calcium compounds used to remove

A

Calcium compounds are also used to remove sulfur dioxide from flue gases in a process known as sulfur scrubbing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How is barium sulfate used in medicine

A

A barium meal or barium swallow containing BaSO4 is given to a patient who needs an X-ray on their intestines
Barium absorbs X-rays which means the gut shows up white on the image

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why can barium be used in medicine even though it is toxic?

A

Barium sulfate is insoluble so is not absorbed into the blood

The barium meal or swallow is only a small amount for the patient to ingest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is magnesium hydroxide used for

A

to neutralise excess acid in the stomach and treat constipation. This is because magnesium hydroxide, Mg(OH)2, is partially soluble in water and is used in suspension (known as ‘milk of magnesia’)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the equasion of nuetralising acid in stomach with magnesium hydroxide

A

Mg(OH)2 (s) + 2HCl (aq) → MgCl2 (aq) + 2H2O (l)

26
Q

Why is magnesium hydroxide safe?

A

magnesium hydroxide is only partially soluble making the solution only slightly alkaline (pH ≅ 10) due to the low OH- concentration

27
Q

How is magnesium used for the extraction of titanium from the ore TiO2

A

TiO2 is heated in a stream of chlorine, in the presence of coke, to produce TiCl4

Then titanium is extracted from its chloride by reduction with magnesium (sodium can also be used)

28
Q

titanium is extracted from its chloride by reduction with magnesium equasion

A

TiCl4 (g) + 2Mg (l) → Ti (s) + 2MgCl2 (l)

29
Q

TiO2 is heated in a stream of chlorine equasion

A

TiO2 (s) + 2C (s) + 2Cl2 (g) → TiCl4 (g) + 2CO (g)

30
Q

Mg - Reaction with oxygen

A

Burns easily
Bright white light

31
Q

Ca - Reaction with oxygen

A

Difficult to ignite
Red flame

32
Q

Sr - Reaction with oxygen

A

Difficult to ignite
Red flame

33
Q

Ba - Reaction with oxygen

A

Difficult to ignite
Green flame

34
Q

Mg - Reaction with water

A

Vigorous reaction with steam, no reaction with water

35
Q

Ca - Reaction with water

A

Reacts moderately, forms a hydroxide

36
Q

Sr - Reaction with water

A

Reacts rapidly, forms a hydroxide

37
Q

Ba - reaction with water

A

Reacts rapidly, forms a hydroxide

38
Q

Mg - Reaction with dilute HCl

A

Reacts vigorously

39
Q

Ca - dilute hcl

A

Reacts vigorously

40
Q

Sr - Reacts with dulte HCl

A

Reacts vigorously

41
Q

Ba - Reactions with dilute Hcl

A

Reacts vigorously

42
Q

Mg - Reaction with dilute H2SO4

A

Reacts vigorously

43
Q

Ca - Reaction with dilute H2SO4

A

Reaction slowed by the formation of a sparingly soluble sulfate layer on the metal, stopping hydrogen bubbles from rising

44
Q

Sr - Reaction with dilute H2SO4

A

Reaction is quickly stopped by the formation of an insoluble sulfate layer on the metal

45
Q

Ba - Reaction with dilute H2SO4

A

Reaction is quickly stopped by the formation of an insoluble sulfate layer on the metal

46
Q

The reaction of group 2 metals with oxygen follows the following general equation:

A

2M (s) + O2 (g) → 2MO (s)

Where M is any metal in group 2

Remember than Sr and Ba also form a peroxide, MO2

47
Q

reaction of all metals with water follows the following general equation:

A

M (s) + 2H2O (l) → M(OH)2 (s) + H2 (g)

Be which does not react with water

48
Q

Magnesium reacting with cold water

A

Mg (s) + 2H2O (l) → Mg(OH)2 (aq) + H2 (g)

The solution formed is weakly alkaline (pH 9-10) as magnesium hydroxide is only slightly soluble

49
Q

magnesium is heated in steam

A

when magnesium is heated in steam, it reacts vigorously with steam to make magnesium oxide and hydrogen gas:
Mg (s) + H2O (g) → MgO (s) + H2 (g)

50
Q

What do Group 2 metals react with dilute acids to form

A

colourless solutions of metal salts

51
Q

What happens when some of Group 2 metals react with sulfuric acid rather than hydrochloric,

A

an insoluble sulfate forms

52
Q

The reaction of the metals with dilute HCl follows the following general equation

A

M (s) + 2HCl (aq) → MCl2 (aq) + H2 (g)

53
Q

The reaction of the metals with dilute H2SO4 follows the following general equation

A

M (s) + H2SO4 (aq) → MSO4 (aq) + H2 (g)

Remember that SrSO4 and BaSO4 are insoluble

54
Q

Reactions of group 2 oxides with water

A

All group 2 oxides are basic, except for BeO which is amphoteric (it can act both as an acid and base)

Group 2 oxides react water to form alkaline solutions which get more alkaline going down the group

55
Q

Mg - Reaction with water

A

MgO (s) + H2O (l) → Mg(OH)2 (s)

MgO is only slightly soluble in water, therefore a weakly alkaline solution (pH 10.0) is formed

56
Q

CaO - Reaction with water

A

CaO (s) + H2O (l) → Ca(OH)2 (s)

A vigorous reaction which releases a lot of energy, causing some of the water to boil off as the solid lump seems to expand and open (pH 11.0)

57
Q

What is calcium hydroxide also known as -

A

lime water

58
Q

Group 2 oxides reacting with sulfuric acid.

A

Group 2 sulfates form

The insoluble sulfates form at the surface of the oxide, which means that the solid oxide beneath it can’t react with the acid

This can be prevented to an extent by using the oxide in powder form and stirring, in which case neutralisation can take place

59
Q

Solubility in group 2 carbonates

A

All (except for BeCO3) are insoluble in water

All g will form soluble chloride salts, water and carbon dioxide gas when reacted with dilute hydrochloric acid

The carbonates of Ca, Sr and Ba form as an insoluble sulfate layer on their solid carbonates which stops any further reaction after the initial bubbling (effervescence) of carbon dioxide gas is seen

60
Q

Group 2 Carbonates reacting with Dilute Acids word equasions.

A

carbonate + dilute hydrochloric acid → chloride + water + carbon dioxide

carbonate + dilute sulfuric acid → sulfate + water + carbon dioxide

ALEVEL - Inorganic Chemistry (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions