group 2

• What are the elements in Group 2 commonly called?

  Alkaline earth metals
• Why are Group 2 metals called alkaline earth metals?

  Because their oxides and hydroxides are alkaline
• What is the trend in reactivity of Group 2 elements?

  Reactivity increases going down the group
• What are the physical properties of Group 2 elements from magnesium to barium?

  • Atoms get larger down the group
  • Atomic radii increase due to extra filled electron levels
  • High melting points typical of giant metallic structures
  • Melting points decrease slightly down the group
• What is the electron arrangement for Group 2 elements?

  Two electrons in an outer s-orbital
• How does the atomic size change in Group 2 elements?

  Atoms get bigger going down the group
• What happens to the melting points of Group 2 elements as you go down the group?

  Melting points decrease slightly down the group
• Why do melting points decrease down Group 2 elements?

  Electrons are further from the positive nuclei
• What is the anomaly in the melting point trend of Group 2 elements?

  Magnesium has the lowest melting point
• What do Group 2 elements do in their reactions?

  They lose two outer electrons to form ions
• How do first and second ionisation energies change down Group 2?

  Both decrease going down the group
• Why does it take less energy to remove electrons down Group 2?

  Electrons are further from the positive nucleus
• What is the general reaction of Group 2 metals with water?

  • M(s) + 2H₂O(l) → M(OH)₂(aq) + H₂(g)
  • Reactivity increases down the group
  • Magnesium reacts slowly with cold water
  • Calcium reacts vigorously with cold water
• What is magnesium hydroxide commonly known as?

  Milk of magnesia
• What is the use of calcium hydroxide?

  To treat acidic soil
• What is the reaction of titanium chloride with magnesium?

  TiCl₄(l) + 2Mg(s) → 2MgCl₂(s) + Ti(s)
• What are the trends in solubility for Group 2 hydroxides and sulfates?

  • Hydroxides: More soluble down the group
  • Magnesium hydroxide is almost insoluble
  • Calcium hydroxide is sparingly soluble
  • Sulfates: Less soluble down the group
  • Barium sulfate is virtually insoluble
• What is the solubility of magnesium hydroxide?

  Almost insoluble
• Why is barium sulfate used in medical X-rays?

  It is virtually insoluble and absorbs X-rays
• What happens when barium chloride is added to a sulfate solution?

  A white precipitate of barium sulfate forms
• What is the oxidation number of all Group 2 elements in their compounds?

  +2
• Why does it become easier to form +2 ions going down Group 2?

  Electrons are further from the nucleus
• What is a redox reaction in the context of Group 2 elements?

  Oxidation is loss of electrons
• How does strontium's reaction with water compare to calcium's?

  Strontium reacts more vigorously than calcium
• How would you predict the solubility of radium compounds compared to other Group 2 members?

  Radium compounds are likely more soluble
• What is the implication of using lime in agriculture?

  It neutralizes acidic soils for better growth
• What factors should be considered when choosing between lime and slaked lime?

  Cost, availability, and effectiveness