In their compounds, what oxidation number do these atoms have? What type of compounds do they form?
2+. Ionic
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What energies are required to form an ionic bond? Why is this?
the 1st and 2nd ionisation energies. Because the outer 2 electrons are relatively easy to remove.
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What is the general equation for forming an ionic bond from one of these atoms? (If M is any group 2 metal)
M (g) -------------- M (g)2+ + 2e-
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What is the trend of 1st ionisation energies down the group?Why is this?
Decreases down the group. the outer electron gets easier to remove as it is further away from the nucleus (greater atomic radius) and is affecgted by electron shielding.
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What causes group 2 metals to be harder and denser than Na & K? Why is this?
They form giant metallic structures. Because there are two valence electrons involved instead of one.
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What is the trend of melting points down this group? Why is this?
Decreases slightly down the group from calcium, Because the atmoic radii increase causing the sea of delocalised electrons in the metallic structures attraction to the metal cation decrease.
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What type of agents are these elements? What is the trend of electropositivity down the group?
Strong reducing agents. They become more electropositive down the group.
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What is the general equation when an earth metal reacts with water? (If M is any group 2 metal)
M(s) + 2H2O ------------ M(OH2) (aq) + H2 (g)
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The reactions of strontium and barium react with water more vigorously. What does each of them form?
Sr reacts to form Strontium Hydroxide. Ba reacts to form Barium Hydroxide.
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What physical property do all these hydroxides have? What is the trend in solubility of them down the group?
White Solids. They become more soluble down the group.
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What are the two key properties of Barium? How does this allow it to be used medically?
Virtually insoluble and highly toxic. Its a very heavy atom and is good at absorbing X-rays so is taken to line the gut before an X-ray. (isnt dissolved in body)
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What can the insolubility of Barium Sulphate provide a test for?
Sulphate ions in solution.
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Outline how Barium Chloride incorporates in the test for sulphate ions in solution where Barium Sulphate (insoluble) is the product).
BaCl2 is added to test solution after it has been acidified with nitric or HCl. If a sulphate ion is present in the solution, a white precipitate is seen.
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Other cards in this set
Card 2
Front
In their compounds, what oxidation number do these atoms have? What type of compounds do they form?
Back
2+. Ionic
Card 3
Front
What energies are required to form an ionic bond? Why is this?
Back
Card 4
Front
What is the general equation for forming an ionic bond from one of these atoms? (If M is any group 2 metal)
Back
Card 5
Front
What is the trend of 1st ionisation energies down the group?Why is this?
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