Group 2

• What happens to atomic radius as one goes down a group?

  Atomic radius increases down the group
• Why do atoms get bigger down a group?

  Atoms have more shells of electrons
• What happens to the outermost electrons as you go down a group?

  They are held more weakly due to distance
• What causes outer shell electrons to be more shielded?

  Repulsive force of inner shell electrons
• 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?

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

  It reacts slowly without a flame
• What is the reaction equation for magnesium and oxygen?

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

  It gives false results in reaction rates
• What is the reaction equation for magnesium with hydrochloric acid?

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

  MgO + 2 HCl → MgCl2 + H2O
• What happens when group 2 metals react with oxygen?

  They burn and produce magnesium oxide
• 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 reaction equation for magnesium 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 equation for calcium with water?

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

  Sr + 2 H2O → Sr(OH)2 + H2
• What is the reaction equation for 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 reaction between magnesium with steam and warm water?

  Steam produces magnesium oxide with flame
• What is the reaction equation for magnesium with warm water?

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

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

  Titanium carbide is formed instead
• 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
• What is the second step in extracting titanium?

  TiCl4 is purified by fractional distillation
• What is the third step in extracting titanium?

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

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

  It reacts with sulfur dioxide in neutralization
• What is the reaction equation for calcium oxide and sulfur dioxide?

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

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

  Barium chloride solution acidified with HCl
• 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 ion testing?

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

  It has low solubility and is not absorbed
• What indicates the presence of carbonates in a reaction?

  Fizzing due to CO2 release