Group 2, the alkaline earth metals

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  • Created by: Heather
  • Created on: 01-03-15 18:21
What are the elements in group 2 called and why?
The alkaline earth metals as their oxides and hydroxides are alkaline,
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Describe how the atomic radius changes as we go down group 2?
The atomic radius of atoms increase as we go down Group 2 as each element has an extra filled main level of electrons compared with the one before it,
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Do Group 2 metals generally have low melting points?
No they are high,
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Describe how the melting points change as we go down Group 2 and why?
They decrease as we go down the group as the 'sea' of delocalised electrons are further away from the positive nuclei and as a result, the strength of the metallic bonds decrease as we go down the group,
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Describe why magnesium is not included in the melting point trend?
AS magnesium doesnt fit the trend becuase the lattice arrangement of atoms is different from that of the elements in Group 2 so it makes them easier to separate,
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Describe how first and second ionisation energies change as we go down Group 2?
They decrease as it takes less energy to remove the electrons as they become further and further away from the positive nucleus which becomes more shilded by more inner shells of electrons,
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Describe the metals reactivity as we go down group 2 and why?
Group 2 metals get more reactive as the 2 outer electrons become further away from the positive nucleus and are more shileded by inner shells of electrons so the two electrons have less attraction holding them to the atom and are more likely to react
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What is the definition of oxidation and what does this mean for Group 2 metals?
Oxidation is the loss of electrons so in all their reactions, the Group 2 metals are oxidised,
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In all their reactions, what oxidation states do the metals go from and to?
They go from oxidation state of 0 to +2
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When reacting with water, describe their reactivity down the group?
The metals react more with water as we go down the group,4
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What is the general reaction equation for Group 2 metals to react with water
M(s) + 2H20(l) = M(OH)2(aq) + H2(g)
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If magneisum reacts slowly with cold water, what does it react rapidly with?
steam
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Give the equation for magnesium reacting with steam
Mg(s) + H20(g) = MgO(s) + H2(g)
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Explain why water should not be used to put out a fire in which magnesium is burning?
As hydrogen is produced when magnesium reacts with water in heat. Hydroen is flammable and there is a risk of an explosion,
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What is magnesium hydroxide used for?
It is used in indigestion remedies to neutralise stomach acid,
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What is calcium hydroxide often refered to as and what is its use?
-Slaked lime, -It is used to treat acidic soil
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What is the trend in solubilities of the Group 2 hydroxides?
They become more soluble as we go down group 2,
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What form are all hyroxides?
White solids,
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Which hydroxide is the most insoluble?
magnesium hydroxide,
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Which hydroxide is most soluble and what does it dissolve to produce?
barium Hydroxide dissolves to rpoduce a strongly alkaline solution
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Give the equation to show barium hydroxide dissolving?
Ba(OH)2(s) + aq = Ba2+(aq) +2OH-(aq)
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What is the trend in solubilities of the Group 2 sulfates?
They becomes less soluble (insoluble) as we go down Group 2,
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Which sulfate is nearly insoluble?
Barium sulfate,
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What is the use of barium sulfate?
It is used to outline the gut in medical X-rays as it is very good at absorbing x-rays,
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is barium sulfate safe to use and why?
Yes as it is so insoluble, it will not react with the water in our bodies,
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What test is barium sulfate used for?
To test for sulfate ions in solution,
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What is first added to the solution?
nitric or hydrochloric acid to acidify it,
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Why is acid added to the solution?
To remove any carbonate ions as carbon dioxide
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Why is it important to remove carbonate ions?
As barium carbonate forms also a white insoluble solid which would be indistinguishable from barium sulfate,
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What is secondly added to the solution?
Barium chloride solution
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If a sulfate is present, what should form?
A white precipitate
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Give the ionic equation to show the formation of barium sulfate?
Ba2+(aq) + SO42-(aq) = BaSO4(s)
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Other cards in this set

Card 2

Front

Describe how the atomic radius changes as we go down group 2?

Back

The atomic radius of atoms increase as we go down Group 2 as each element has an extra filled main level of electrons compared with the one before it,

Card 3

Front

Do Group 2 metals generally have low melting points?

Back

Preview of the front of card 3

Card 4

Front

Describe how the melting points change as we go down Group 2 and why?

Back

Preview of the front of card 4

Card 5

Front

Describe why magnesium is not included in the melting point trend?

Back

Preview of the front of card 5
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