Group 2

• What happens to atomic radius down a group?

  Atomic radius increases down the group
• Why does atomic radius increase down a group?

  Atoms have more shells of electrons
• How does the outermost electron's attraction change down a group?

  They are held more weakly due to distance
• What effect do inner shell electrons have on outer shell electrons?

  They shield outer electrons from the nucleus
• What trend occurs in melting points down Group 2?

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

  Metallic bonding weakens as atomic size increases
• What happens to the distance between positive ions and delocalized electrons down Group 2?

  The distance increases as atomic size increases
• How does reactivity change down Group 2 metals?

  Reactivity increases down the group
• What happens to magnesium when it reacts with oxygen?

  It forms magnesium oxide and burns with a white flame
• What is the equation for magnesium reacting with oxygen?

  2 Mg + O2 → 2 MgO
• Why must magnesium oxide be removed before reactions?

  It reacts at different rates than magnesium
• What is the reaction of magnesium with hydrochloric acid?

  Mg + 2 HCl → MgCl2 + H2
• What is the reaction of magnesium oxide with hydrochloric acid?

  MgO + 2 HCl → MgCl2 + H2O
• How do group 2 metals react with oxygen?

  They burn in oxygen producing metal oxides
• What is the appearance of magnesium oxide?

  It appears as a white powder
• What is produced when magnesium reacts with steam?

  Magnesium oxide and hydrogen are produced
• What is the equation for magnesium reacting with steam?

  Mg(s) + H2O(g) → MgO(s) + H2(g)
• How do other group 2 metals react with cold water?

  They react with increasing vigor down the group
• What is the reaction of calcium with water?

  Ca + 2 H2O → Ca(OH)2 + H2
• What is the reaction of strontium with water?

  Sr + 2 H2O → Sr(OH)2 + H2
• What is the reaction of barium with water?

  Ba + 2 H2O → Ba(OH)2 + H2
• What do the hydroxides produced in reactions with water do?

  They make the water alkaline if soluble
• What observations indicate a reaction with water?

  Fizzing, metal dissolving, solution heating
• What is the difference in magnesium's reaction with warm water compared to steam?

  It is slower and no flame occurs
• What is the equation for magnesium reacting with warm water?

  Mg + 2 H2O → Mg(OH)2 + H2
• Why is titanium useful in alloys?

  It is abundant, low density, and corrosion resistant
• Why can't titanium be extracted with carbon?

  Titanium carbide forms instead of titanium
• Why can't titanium be extracted by electrolysis?

  It must be very pure for electrolysis
• What is the first step in extracting titanium?

  TiO2 is converted to TiCl4 at 900°C
• How is TiCl4 purified?

  By fractional distillation in an argon atmosphere
• What is the final step in extracting titanium?

  Ti is extracted by Mg at 500°C
• Why is titanium expensive to extract?

  Due to magnesium cost and batch process
• What is the role of calcium oxide in flue gas desulfurization?

  It reacts with sulfur dioxide in a neutralization reaction
• What is the reaction of sulfur dioxide with calcium oxide?

  SO2 + CaO → CaSO3
• What happens to group II sulfates down the group?

  They become less soluble down the group
• What reagent is used to test for sulfate ions?

  Barium chloride solution acidified with hydrochloric acid
• What happens when barium chloride is added to sulfate ions?

  A white precipitate of barium sulfate forms
• What is the simplest ionic equation for sulfate testing?

  Ba2+(aq) + SO4^2-(aq) → BaSO4(s)
• Why is barium sulfate safe for medical use?

  It is not absorbed into the blood
• What is observed when a carbonate is present in a reaction?

  Fizzing due to CO2 is observed