Group 2

• What happens to atomic radius as one goes down a group in the periodic table?


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


  Atoms have more shells of electrons, making the atom bigger.
• What happens to the outermost electrons as you go down a group regarding ionization energy?


  The outermost electrons are held more weakly because they are further from the nucleus.
• What effect do inner shell electrons have on outer shell electrons?


  Inner shell electrons shield outer shell electrons from the nucleus's attraction.
• What trend is observed in the melting points of Group 2 metals?


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


  The metallic bonding weakens as atomic size increases, increasing distance between ions and electrons.
• How does the reactivity of Group 2 metals change down the group?


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


  Magnesium reacts slowly in oxygen without a flame, forming magnesium oxide.
• What is the balanced equation for the reaction of magnesium with oxygen?

  $2 \text{Mg} +$$\text{O}_2 \rightarrow 2 \text{MgO}$
• Why must magnesium oxide be removed before conducting reactions with magnesium ribbon?


  To avoid false results due to different reaction rates of Mg and MgO.
• What is the balanced equation for the reaction of magnesium with hydrochloric acid?

  $\text{Mg} +$$2 \text{HCl} \rightarrow \text{MgCl}_2 +$$\text{H}_2$
• What is the balanced equation for the reaction of magnesium oxide with hydrochloric acid?

  $\text{MgO} +$$2 \text{HCl} \rightarrow \text{MgCl}_2 +$$\text{H}_2\text{O}$
• What do Group 2 metals do when they react with oxygen?


  They burn in oxygen, producing magnesium oxide.
• What is the appearance of magnesium oxide when formed?


  MgO appears as a white powder.
• What is the reaction of magnesium with steam?


  Magnesium reacts in steam to produce magnesium oxide and hydrogen.
• What is the balanced equation for the reaction of magnesium with steam?

  $\text{Mg}(s) +$$\text{H}_2\text{O}(g) \rightarrow \text{MgO}(s) +$$\text{H}_2(g)$
• How do the other Group 2 metals react with cold water?


  They react with increasing vigor down the group to form hydroxides.
• What is the balanced equation for the reaction of calcium with water?

  $\text{Ca} +$$2 \text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2 +$$\text{H}_2$
• What is the balanced equation for the reaction of strontium with water?

  $\text{Sr} +$$2 \text{H}_2\text{O} \rightarrow \text{Sr(OH)}_2 +$$\text{H}_2$
• What is the balanced equation for the reaction of barium with water?


  $\text{Ba} +$$2 \text{H}_2\text{O} \rightarrow \text{Ba(OH)}_2 +$$\text{H}_2$
• What observable effects occur when Group 2 metals react with water?


  Fizzing, metal dissolving, solution heating up, and precipitate formation with calcium.
• What is the difference in the reaction of magnesium with steam compared to warm water?


  The reaction with steam is much faster and produces magnesium oxide with a flame, while warm water reaction is slower without a flame.
• What is titanium used for?


  Titanium is used for making strong, light alloys for use in aircraft.
• Why can't titanium be extracted with carbon?


  Because titanium carbide (TiC) is formed rather than titanium.
• Why can't titanium be extracted by electrolysis?


  Because it has to be very pure for electrolysis.
• How is titanium extracted?


  By reaction with a more reactive metal, such as magnesium.
• What are the steps in extracting titanium?

  1. Convert TiO2 (solid) to TiCl4 (liquid) at 900°C.
  2. Purify TiCl4 by fractional distillation in an argon atmosphere.
  3. Extract Ti by reaction with Mg in an argon atmosphere at 500°C.
• Why is titanium expensive to extract?


  Due to the cost of magnesium, batch processing, argon use, moisture removal, and high temperatures required.
• What is the balanced equation for the extraction of titanium using magnesium?

  $\text{TiCl}_4 +$$2 \text{Mg} \rightarrow \text{Ti} +$$2 \text{MgCl}_2$
• How does calcium oxide help in flue gas desulfurization?


  It reacts with sulfur dioxide to neutralize it, forming calcium sulfite.
• What is the balanced equation for the reaction of sulfur dioxide with calcium oxide?

  $\text{SO}_2 +$$\text{CaO} \rightarrow \text{CaSO}_3$
• What happens to the solubility of Group II sulfates down the group?


  Group II sulfates become less soluble down the group.
• Which Group II sulfate is the least soluble?


  Barium sulfate (BaSO4) is the least soluble.
• How can sulfate ions be tested for in a solution?


  By adding acidified barium chloride, which forms a white precipitate of barium sulfate.
• What is the simplest ionic equation for the reaction of barium ions with sulfate ions?

  $\text{Ba}^{2+}(aq) +$$\text{SO}_4^{2-}(aq) \rightarrow \text{BaSO}_4(s)$
• Why is barium sulfate safe to use in medical imaging despite being toxic?


  Because its low solubility means it is not absorbed into the blood.
• What observable effect indicates the presence of carbonates when reacting with hydrochloric acid?


  Fizzing due to the release of carbon dioxide (CO2).
• What happens when barium metal reacts with sulfuric acid?


  It reacts slowly due to the insoluble barium sulfate forming a barrier.
• What is the balanced equation for the reaction of barium with sulfuric acid?


  $\text{Ba} +$$\text{H}_2\text{SO}_4 \rightarrow \text{BaSO}_4 +$$\text{H}_2$
• Why can't sulfuric acid be used to test for sulfate ions?


  Because it contains sulfate ions and would give a false positive result.