Chapter 8.2 - Group 2 Alkaline Earth Metas Flashcards
This question is about the elements in Group 2 and their compounds.
Use the Periodic Table to deduce the full electron configuration of calcium (1)
1s2 2s2 2p6 3s2 4s2
Write an ionic equation, with state symbols, to show the reaction of calcium with an excess of water. (1)
Ca(s) + 2H2O(l) = Ca+2(aq) + 2OH-(aq) + H2(g)
State the role of water in the reaction with calcium. (1)
Oxidizing agent
Write an equation to show the process that occurs when the first ionisation energy of calcium is measured. (1)
Ca(g) = Ca+(g) + e-
State and explain the trend in the first ionisation energies of the elements in Group 2 from magnesium to barium (3)
- decreases,
- weak attraction of ion to lost electron,
- shielding increases,
- atoms get bigger
State the trend in atomic radius for atoms of the elements down Group 2 from Mg to Ba
Give a reason for this trend (2)
- increases,
- more shells
State a medical use of barium sulfate.
State why this use of barium sulfate is safe, given that solutions containing barium ions are poisonous (2)
- to help diagnose problems in the esophagus ,
- BaSO4, it is insoluble
Write an equation for the reaction of magnesium hydroxide with hydrochloric acid. (1)
Mg(OH)2 + 2HCL = MgCl2 + 2H2O
Solutions of barium hydroxide are used in the titration of weak acids.
State why magnesium hydroxide solution could not be used for this purpose. (1)
Magnesium hydroxide is insoluble
Magnesium metal is used to make titanium from titanium(IV) chloride.
Write an equation for this reaction of magnesium with titanium(IV) chloride. (1)
TiCl4 + 2Mg = 2MgCl2 + Ti
your knowledge of the reactions of Group 2 metals with water to explain why
water should not be used to put out a fire in which magnesium metal is burning. (2)
- Hydrogen is produced,
- highly flammable and risk of explosion
Explain why calcium has a higher melting point than strontium (2)
- delocalized electrons closer to cations
- strong attraction between positive ions and delocalized electrons,
- more delocalized electrons
Give the formula of a Group 2 metal hydroxide used in agriculture (1)
Ca(OH)2
State the trend in reactivity with water of the Group 2 metals from Mg to Ba (1)
-reactivity with water increases down the group
Write an equation for the reaction of barium with water. (1)
Ba + 2H2O = Ba(OH)2 + H2
Give the formula of the least soluble hydroxide of the Group 2 metals from Mg to Ba (1)
Mg(OH)2
State how barium sulfate is used in medicine.
Explain why this use is possible, given that solutions containing barium ions are poisonous. (2)
- Barium sulfate is given in a meal to outline the gut
- barium sulphate is insoluble
From Mg(OH)2 to Ba(OH)2, the solubility in water
Decreases,
Increases,
Stays the same. (1)
Increases
From Mg to Ba, the first ionisation energy
decreases.
increases.
stays the same (1)
Decreases
From Mg to Ba, the atomic radius
Decreases.
Increases.
Stays the same (1)
Increases
Explain why calcium has a higher melting point than strontium. (2)
- strong attraction between positive ions and delocalized electrons,
- delocalized electrons closer to cations
Write the simplest ionic equation for the reaction that occurs when acidified barium chloride solution is added to a solution containing sulfate ions. (1)
Ba2+ + SO42– = BaSO4 O