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
State why sulfuric acid should not be used to acidify the barium chloride (1)
Sulphuric acid contains sulfate ions
Magnesium ribbon reacts with hot water. Heated magnesium ribbon reacts with steam. State two differences between these reactions (2)
- slower with hot water,
- hot water produces hydroxides and steam produces the oxide
Use your knowledge of the solubilities of Group 2 sulfates to explain why these reactions of magnesium and calcium with dilute sulfuric acid are so different. (3)
- magnesium sulfate is soluble,
- calcium sulfate is insoluble,
- calcium sulfate coats the surface of the calcium,
- coating prevents further reaction with the acid
State one use of barium sulfate in medicine.
Explain why this use is possible, given that solutions containing barium ions are poisonous (2)
- to help diagnose problems in the esophagus,
- barium sulfate is insoluble
State which of the first, second or third ionisations of aluminium would produce an ion with the electron configuration 1s2 2s2 2p6 3s1 (1)
2nd
Explain why the value of the first ionisation energy of sulfur is less than the value of the first ionisation energy of phosphorus (2)
-paired electrons in 3p orbital repel
Identify the element in Period 2 that has the highest first ionisation energy and give its electron configuration (2)
- neon,
- 1s2 2s2 2p6
State the trend in first ionisation energies in Group 2 from beryllium to barium. Explain your answer in terms of a suitable model of atomic structure (3)
- decreases,
- atomic radius increases,
- electrons removed further from the nucleus
Write an equation for the reaction between barium hydroxide and sulfuric acid (1)
Ba(OH)2 + H2SO4 = BaSO4 + 2H2O
State a use of magnesium hydroxide in medicine (1)
Neutralize acidity
Explain why the rate of this reaction decreases when the temperature of the water in the lake falls. (3)
- decrease in T decreases the energy of the particles,
- less particles have energy greater than the activation energy,
- less successive collisions
Explain why strontium has a higher melting point than barium. (2)
- delocalized electrons closer to cations,
- strong metallic bond or strong attraction between positive ions and delocalized electrons
Write an equation for the reaction of strontium with water (1)
Sr+2H2O→Sr(OH)2 +H2
Use your knowledge of Group 2 sulfates to explain why the magnesium sulfate formed is easy to separate from the titanium (1)
Magnesium sulphate is soluble
State the trend in the reactivity of the Group II elements Mg–Ba with water. (2)
- reactivity increases down the group,
- Ba+2H2O→Ba(OH)2 +H2
Which one of the following is the electron arrangement of the strongest reducing agent?
A 1s2 2s2 2p5
B 1s2 2s2 2p6 3s2
C 1s2 2s2 2p6 3s2 3p5
D 1s2 2s2 2p6 3s2 3p6 4s2 (1)
D
State the trends in solubility of the hydroxides and of the sulphates of the Group II elements Mg–Ba. (2)
- solubility increases for hydroxides,
- solubility decreases for sulphates
State the trend in atomic radius down Group 2 from Mg to Ba and give a reason for this trend (2)
- increases,
- more energy levels
State and explain the trend in melting points of the elements down Group 2 from Mg to Ba.
(2)
- decreases,
- weak metallic bonds,
- large ions
State the trend in reactivity with water of the elements down Group 2 from Mg to Ba. Write an equation for the reaction of magnesium with steam and an equation for the reaction of strontium with water (3)
Trend: increases,
Equation for Mg: Mg + H2O → MgO + H2,
Equation for Sr: Sr+2H2O→Sr(OH)2 +H2
Sulfates of the Group 2 elements from Mg to Ba have different solubilities.
Give the formula of the least soluble of these sulfates and state one use that depends upon the insolubility of this sulfate (2)
Formula:
Use:
- BaSO4,
- test for sulfate ions
How to metals react with carbonate (CO3) -2 ?
metal carbonate + acid = CO2 + salt + H2O
Other than cost, explain one advantage of using magnesium hydroxide rather than magnesium carbonate to reduce acidity in the stomach (1)
Does not produce CO2
Write the simplest ionic equation for the reaction that occurs between magnesium chloride and sodium hydroxide.
Include state symbols in your equation. (1)
Mg+2(aq) + 2OH-(aq) = Mg(OH)2 (s)
Other than cost, explain one advantage of using magnesium hydroxide rather than magnesium carbonate to reduce acidity in the stomach. (1)
Does not produce CO2
Describe and explain the trend, down the group, in the reactivity of the Group 2 elements with water. (5)
- reactivity increases down the group,
- atomic radius increases,
- increase in shielding,
- increased nuclear charge,
- ionization energy decreases
A student added an excess of hydrochloric acid to an old sample of magnesium oxide that is contaminated with magnesium carbonate.
State two observations that the student would make (3)
-solid dissolves,
-fizzing,
MgO + 2HCl → MgCl2 + H2O
MgCO3 + 2HCl → MgCl2 + CO2 + H2O
Explain why barium is more reactive than calcium. (4)
- barium ions are larger,
- barium atoms have more shielding,
- this outweighs-the increase in nuclear charge
- barium electrons are lost easily,
Write the equation for the reaction of magnesium with oxygen. (1)
2!g + O2 = 2MgO
Describe the trend in solubility of the sulfate in group 2
-decreases
Describe the trend in solubility of the hydroxide as you go down group 2
-Increases
Using equations describe how calcium oxide or calcium carbonate can be used to reduce sulfur dioxide emissions (2)
CaO + SO2 = CaSO4
CaCO3 + SO2 = CaSO3 + CO2
But calcium oxide is more suitable bcoz in the next reaction CO2 is produced
State the use of barium sulfate in medicine (BaSO4)
Use: (1)
Use: to help diagnose or find problems in the esophagus and stomach
student added a few drops of concentrated sulfuric acid to solid sodium bromide.
Give two observations that the student would make.
Write an ionic equation for the redox reaction.
Observations lonic equation (4)
Observation: brown/ orange gas, choking gas
Equation: SO4^-2 + 2Br- 4H+ = SO2 + Br2 + 2H2O