2.2 Group 2 Flashcards

1
Q

What happens to group 2 elements’ electrons when they react to form an ion?

A

Group 2 elements lose two electrons when they react.

see page 96 in the revision guide

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2
Q

Does the atomic radius increase or decrease down group 2?

Draw a general graph for the atomic radius down group 2 elements.

A

Atomic radius increases down a group.
As one goes down the group, the atoms have more shells of electrons making the atom bigger.

(see page 96 in the revision guide)

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3
Q

Why does reactivity increase down group 2?

A

The outermost electrons are held more weakly because they are successively further from the nucleus in additional shells.
In addition, the outer shell electrons become more shielded from the attraction of the nucleus by the repulsive force of inner shell electrons.

(see page 96 in the revision guide)

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4
Q

Does the melting point decrease or increase down group 2?

Draw a general graph for this.

A

Melting points decrease down the group. The metallic bonding weakens as the atomic size increase. The distance between the positive ions and delocalised electrons increases. Therefore the electrostatic attractive forces between the positive ions and the delocalised electrons weaken.

(see page 96 in the revision guide)

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5
Q

How do group 2 elements react with water?

A

(see page 97 in the revision guide)

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6
Q

What does the solubility trend depend on in group 2?

A

(see page 98 in the revision guide)

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7
Q

What are group 2 compounds used for?

A

Group 2 compounds are used to neutralise acidity.

see page 98 in the revision guide

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8
Q

What is barium sulphate used in?

A

Barium sulphate is used in ‘Barium Meals’.

see page 98 in the revision guide

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9
Q

What is magnesium used in?

A

Magnesium is used in the extraction of titanium.

see page 99 in the revision guide

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10
Q

What are calcium oxide and calcium carbonate used for?

A

Calcium oxide and calcium carbonate remove sulfur dioxide.

see page 99 in the revision guide

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11
Q

Does the boiling point increase or decrease down group 7?

A

The booking point increases down group 7.

see page 100 in the revision guide

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12
Q

Does electronegativity increase or decrease down group 7?

A

Electronegativity decreases down group 7.

see page 100 in the revision guide

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13
Q

What is the formula, colour, physical state and electronic configuration of the atoms of the halogens: Fluorine, Chlorine, Bromine and Iodine.

A

(see page 100 in the revision guide)

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14
Q

What does Chlorine and Sodium Hydroxide make and how?

A

Chlorine and sodium hydroxide makes bleach.

see page 100 in the revision guide

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15
Q

What is chlorine used for?

A

Chlorine is used to kill bacteria in water.

see page 101 in the revision guide

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16
Q

Does the reducing power of halides increase or decrease down the group?

Why?

A

The reducing power of halides increases down the group.

  • The ions get bigger, so the electrons are further away from the positive nucleus.
  • Their are extra inner electron shells so there’s a greater shielding effect.

(see page 102 in the revision guide)

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17
Q

How do halides react with sulphuric acid?

Draw an equation for F, Br and I.

A

(see page 102 in the revision guide)

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18
Q

How do you test for halides?

What are the results?

A

(see page 103 in the revision guide)

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19
Q

How do you test for group 2 ions?

What are the results?

A

(see page 104 in the revision guide)

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20
Q

How do you test for ammonium ions?

What are the results?

A

(see page 104 in the revision guide)

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21
Q

How do you test for Sulfates?

What are the results?

A

(see page 104 in the revision guide)

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22
Q

How do you test for hydroxides?

What are the results?

A

(see page 104 in the revision guide)

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23
Q

How do you test for Halides?

What are the results?

A

(see page 105 in the revision guide)

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24
Q

How do you test for carbonates?

What are the results?

A

(see page 105 in the revision guide)

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25
Q

What colour is the flame when burning magnesium?

A

Mg burns with a bright white flame.

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26
Q

Write the equation for the reaction of Mg with O2.

A

2Mg + O2 -> 2MgO

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27
Q

What is MgO’s physical state?

A

MgO is a white solid with a high melting point due to its ionic bonding.

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28
Q

Why does Mg ribbon need to be cleaned before testing reaction rates of Mg with an acid, and what is it cleaned with?

A

Mg will react slowly with oxygen without a flame. Mg ribbon will often have a thin layer of magnesium oxide on it formed by reaction with oxygen.

This needs to be cleaned off by emery paper before doing reactions with Mg ribbon.
If testing for reaction rates with Mg and acid, an un-cleaned Mg ribbon would give a false result because both the Mg and MgO would react but at different rates.

Mg + 2HCl -> MgCl2 + H2
MgO + 2HCl -> MgCl2 + H2O

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29
Q

Give the differences in the reactions of Mg with steam and water.

A

(see page 1 in the chemrevise revision guide)

30
Q

Give the equation for Ca reacting with cold water. What would you observe?

A

(see page 1 in the chemrevise revision guide)

31
Q

Give the equation for Sr reacting with cold water. What would you observe?

A

(see page 1 in the chemrevise revision guide)

32
Q

Give the equation for Ba reacting with cold water. What would you observe?

A

(see page 1 in the chemrevise revision guide)

33
Q

Why is titanium a useful metal?

A

Titanium is a useful metal because it is abundant, it has a low density and is corrosion resistant.

e.g. It is used for making strong, light alloys for us in aircraft.

34
Q

How is titanium extracted?

A

Titanium is extracted by a reaction with a more reactive metal. (e.g. Mg)

35
Q

Give the 3 steps in the extraction of titanium.

Draw the 2 equations for this process.

A
  1. TiO2 (solid) is converted to TiCl4 (liquid) at 900ºC
  2. The TiCl4 is purified by fractional distillation is an argon atmosphere.
  3. The Ti is extracted by Mg in an argon atmosphere at 500ºC

(see page 2 in the chemrevise revision guide for equations)

36
Q

Why is titanium expensive? 4 reasons.

A

(see page 2 in the chemrevise revision guide)

37
Q

Why can’t titanium be extracted with carbon?

A

Titanium cannot be extracted with carbon because titanium carbide (TiC) is formed rather than titanium.

38
Q

Why can’t titanium be extracted by electrolysis?

A

Titanium cannot be extracted by electrolysis because it has to be very pure.

39
Q

Why is TiO2 converted into TiCl4 rather than remaining TiO2 when extracting titanium?

A

TiO2 is converted to TiCl4 as it can be purified by fractional distillation, TiCl4 being molecular (liquid at room temperature) rather than ionic like TiO2 (solid at room temperature)

40
Q

Is magnesium hydroxide soluble in water?

A

Magnesium hydroxide is classed as insoluble in water.

41
Q

Give the simplest ionic equation for the formation of Mg(OH)2(s)

A

(see page 3 in the chemrevise revision guide)

42
Q

What is magnesium hydroxide used for?

A

Magnesium hydroxide is used in medicine (in suspension as milk of magnesia) to neutralise excess acid in the stomach and to treat constipation.

It is safe to use because it is so weakly alkaline. It is preferable to using calcium carbonate as it will not produce carbon dioxide.

43
Q

Draw the equation for the reaction of Magnesium hydroxide with stomach acid.

A

Mg(OH)2 + 2HCl -> MgCl2 + 2H2O

44
Q

Is calcium hydroxide soluble in water?

A

Calcium hydroxide is classed as partially soluble in water.

45
Q

What is calcium hydroxide used for?

A

Calcium hydroxide is used in agriculture to neutralise acidic soils.

46
Q

What would the pH appear as of a suspension of magnesium hydroxide in water?

A

Slightly alkaline (ph9)

47
Q

What would the pH appear as of a suspension of calcium hydroxide in water?

A

pH 11

48
Q

Why is calcium hydroxide more soluble in water than magnesium hydroxide?

A

A suspension fo calcium hydroxide in water will appear more alkaline (pH11) than magnesium hydroxide as it is more soluble so there will be more hydroxide ions present in solution.

49
Q

What is an aqueous solution of calcium hydroxide used for?

A

An aqueous solution of calcium hydroxide is called lime water and can be used to test for carbon dioxide. The lime water turns cloudy as white calcium carbonate is produced.

50
Q

Write the equation of the formation of calcium carbonate in lime water.

A

Ca(OH)2(aq) + CO2(g) -> CaCO3(s) + H2O(l)

51
Q

Is barium hydroxide soluble in water?

A

Barium hydroxide would easily dissolve in water.

52
Q

What would the pH appear as of a suspension of barium hydroxide in water?

A

The hydroxide ions present would make the solution strongly alkaline.

53
Q

Draw the ionic equation for barium hydroxide dissolving in an aqueous solution.

A

Ba(OH)2(aq) + aq -> Bq2+ (aq) + 2OH-(aq)

54
Q

Do group 2 hydroxides become more or less soluble down the group?

A

Group 2 hydroxides become more soluble down the group.

55
Q

Write a full and ionic equation for the formation of strontium sulphate.

A

(see page 3 in the chemrevise revision guide)

56
Q

What is barium sulphate used for and why?

A

BaSO4 is used in medicine as a ‘barium meal’ given to patients who need x-rays of their intestines. The barium absorbs the x-rays and so the gut shows up on the x-ray image. Even though barium compounds are toxic, it is safe to use here because its low solubility means it is not absorbed into the blood.

57
Q

Why does barium metal only react slowly with sulphuric acid?

A

If barium metal is reacted with sulfuric acid ti will only react slowly as the insoluble barium sulfate produced will cover the surface of the metal and act as a barrier to further attack.

58
Q

Write the equation for the reaction of barium metal with sulfuric acid.

A

Ba + H2SO4 -> BaSO4 + H2

59
Q

What is BaCl solution acidified with hydrochloric acid used as?

A

BaCl solution acidified with hydrochloric acid is used as a reagent to test for sulphate ions.

60
Q

What will form is acidified barium chloride is added to a solution that contains sulfate ions?

A

If acidified barium chloride is added to a solution that contains sulfate ions a white precipitate of barium sulfate forms.

61
Q

Write the simplest ionic equation for the formation of barium sulfate.

A

(see page 3 in the chemrevise revision guide)

62
Q

Why is hydrochloric acid needed to react with salts when trying to form a specific salt?

A

(see page 3 in the chemrevise revision guide)

63
Q

Write the equation for the formation of NaCl from Na2CO3.

What would be observed in this reaction?

A

2HCl + Na2CO3 -> 2NaCl + H2O + CO2

Fizzing due to CO2 would be observed if a carbonate was present.

64
Q

What is limewater?

A

An aqueous solution of calcium hydroxide.

65
Q

What are precipitation reactions?

A

(see top of page 4 in the chemrevise revision guide)

66
Q

Give some examples of soluble salts and insoluble salts.

not on spec but good to know

A

(see page 4 in the chemrevise revision guide)

67
Q

Draw the apparatus for a gravitational filtration.

A

(see page 4 in the chemrevise revision guide)

68
Q

Draw the apparatus for a vacuum filtration.

A

(see page 4 in the chemrevise revision guide)

69
Q

What are spectator ions?

A

Soectaor ions are ions that are:

  • Not changing state
  • Not changing oxidation number

(so when writing ions equations, leave these ions out)

70
Q

Write the ionic equation for the formation of Barium sulfate using Na2SO4.

A

(see page 4 in the chemrevise revision guide)