2.2 group 2 notes Flashcards Preview

Chemistry > 2.2 group 2 notes > Flashcards

Flashcards in 2.2 group 2 notes Deck (60)
Loading flashcards...
1
Q

what are group 2 MP like

A

high

2
Q

why are group 2 MP high

A

metals have strong metallic bnding

3
Q

are group one or group 2 harder

A

group 2 are harder and have a higher density than group one elements

4
Q

why are group 2 elements harder and have a higher density than group 1 elements

A

ions are smaller and more highly charged therefore ions pack together more closely leading to stronger bonding

5
Q

what are group 2 elements reactivity’s like

A

reactive with similar chemical reactions

6
Q

why are group 2 elements reactive metals with similar chemical reactions

A

they all lose 2 electrons when they react

7
Q

appearance of group 2 compounds

A

white solids/colourless solutions

8
Q

trend in atomic radius in group 2

A

increases down group 2

9
Q

why does atomic radius increase down group 2

A

shells increase
shielding increases
nuclear attraction on outer electrons decreases

10
Q

trend in first IE down group 2

A

decreases

11
Q

why does first IE decrease down group 2

A

shells increase
shielding increases
nuclear attraction on outer electrons decreases

12
Q

trend in melting points down group 2

A

decrease

13
Q

why do melting points decrease down group 2

A
  • ions all have 2+ charge but increase in size

- as ions increase, charge density decreases- attraction/bonding decreases

14
Q

trend in reactivity down group 2

A

increases

15
Q

why does reactivity increase down group 2

A

lose electrons more readily as we go down group because:

  • ions all have 2+ charge but increase in size
  • as ions increase, charge density decreases- attraction/bonding decreases
16
Q

observations of the reaction of magnesium with cold water

A

very slow

few bubbles of gas

17
Q

products of the reaction of magnesium with cold water

A

magnesium hydroxide and hydrogen

18
Q

Products of the reaction of magnesium with steam

A

Magnesium oxide and hydrogen

19
Q

Observations of the reaction between calcium and water

A

Effervescence

Solid Ca dissolves

20
Q

Products of the reaction between calcium and water

A

Calcium hydroxide and hydrogen

21
Q

Observations of the reaction between strontium and water

A

Vigorous fizzing

Solid strontium dissolves

22
Q

Products of reaction between strontium and water

A

Strontium hydroxide and hydrogen

23
Q

Observations of reaction between barium and water

A
  • even more vigorous fizzing

- solid barium dissolves

24
Q

Products of the reaction between barium and cold water

A

Barium hydroxide and hydrogen

25
Q

What is the general trend in reactivity with water of group 2 element as you go down the group

A

Reactivity increases

26
Q

Why is titanium a useful metal

A

Strong, high melting point and high corrosion resistance

27
Q

Where does titanium have many applications

A

In the aerospace, marine and motor vehicle industries

28
Q

Why is it difficult to extract titanium from its ores

A

Because reduction with carbon produces a brittle titanium carbide

29
Q

How is the production of titanium carbide avoided in the extraction of titanium from its ore

A

The titanium oxide ore is first reacted with chlorine and carbon to form titanium chloride

30
Q

What happens to the titanium chloride to produce titanium

A

It is reduced with magnesium to produce titanium

31
Q

What are group 2 hydroxides

A

Bases

32
Q

What do group 2 hydroxides react with

A

Acids

33
Q

Example of acid base reaction between magnesium hydroxide and hydrochloric acid

A

Mg(OH)2 + 2HCL > MgCl2 + 2H20

34
Q

What is magnesium hydroxides solubility like and pH of the solution it makes

A

V sparingly soluble

PH 8-9

35
Q

What is calcium hydroxides solubility like and pH of the solution it makes

A

Not much better than magnesium

pH 10-11

36
Q

What is strontium hydroxides solubility like and pH of the solution it makes

A

Relatively soluble, pH 11-12

37
Q

What is barium hydroxides solubility like and pH of the solution it makes

A

Pretty soluble, pH 12-14

38
Q

What the trend in water solubility of group 2 hydroxides

A

Increases down the group

39
Q

What is the trend in pH of resultant solutions from reaction of group 2 hydroxides and acids

A

Increases down the group

40
Q

How are relative solubilities of group 2 hydroxides tested

A

Adding aqueous sodium hydroxide to the solutions of group 2 ions and observing the precipitate formed

41
Q

What indicates that magnesium hydroxide is sparingly soluble

A

The pH of the solution is slightly alkaline, indicating a small amount of hydroxide ions have dissolved- hence a thick white precipitate will be seen

42
Q

How is it indicated that barium hydroxide is more soluble than magnesium hydroxide

A

Very thin white PPT seen

43
Q

What is magnesium hydroxide used for

A

In medicine

Milk of magnesium

Indigestion medicine- neutralises stomach acid

44
Q

How is calcium hydroxide used

A

To neutralise acidic soil

Obtained from limestone- cheap

45
Q

What is the trend in solubility of group 2 sulfates

A

Decreases down the group

46
Q

What are calcium and barium sulfates’ solubility like

A

Calcium- sparingly soluble

Barium- insoluble

47
Q

How to test the relative solubility of group 2 sulfates

A

Add sulfuric acid/aqueous sodium sulfates to solutions of group 2 ions and observing the precipitates formed

48
Q

What is magnesium sulfate solubility and how would this be seen

A

Soluble- no precipitate

49
Q

What is barium sulfate solubility and how would this be seen

A

Insoluble so a thick white precipitate would be seen

50
Q

What can the solubilities of group 2 hydroxides and sulfates be used to test

A

The identity of group 2 ions in solution

51
Q

Uses of barium salts

A

Tests for sulfates

52
Q

Method for using barium salts to test for sulfates

A
  • add to 1cm3 unknown solution
  • add HCl
  • add 1cm3 BaCl2(aq)
53
Q

Interpretation for using barium salts to test for sulfates

A

White PPT? Sulfate ions present

54
Q

Equation for using barium salts to test for sulfates

A

BaCl2 + Na2SO4 > BaSO4 + 2NaCl

55
Q

Uses of barium sulfate

A

Medicine

56
Q

Barium meal

A

BaSO4- good at absorbing xrays- if ingested provides a good image of the digestive tract via X-ray images

57
Q

Why is using barium sulfate in medicine harmless despite it being toxic

A

Barium sulfate is insoluble so barium ions are not absorbed into the blood

58
Q

Uses of calcium compounds

A

CaO or CaCO3 can be used to remove sulfur dioxide from flue gas

59
Q

Equation of neutralisation of sulfur dioxide using calcium oxide

A

CaO + SO2 > CaSO3

60
Q

Equation for reaction of calcium carbonate with so2

A

CaCO3 + SO2 > CaSO3 + CO2