Group 2, The Alkaline Earth Metals

• Why is barium (Ba) more reactive than magnesium (Mg)?

  Ba has lower ionization energy than Mg
• Write a balanced symbol equation for the reaction of magnesium with oxygen.

  2Mg + O₂ → 2MgO
• What would you observe when magnesium reacts with oxygen?

  Bright white light and white solid
• What is reduction in terms of electrons?

  Gain of electrons
• What happens to magnesium in the redox reaction with oxygen?

  Mg is oxidized, losing electrons
• Why does barium have a lower melting point than magnesium?

  Barium has weaker metallic bonds than magnesium
• How many hydroxide ions are in 5g of magnesium hydroxide?

  10 hydroxide ions
• What characterizes the reactions of group 2 elements?

  • All are redox reactions
  • Oxidation state changes from 0
• What is the balanced equation for calcium reacting with water?

  • Ca (s) + H₂O (l) → Ca(OH)₂ (aq) + H₂ (g)
• What happens when magnesium reacts with hydrochloric acid?

  • Mg (s) + 2HCl (aq) → MgCl₂ (aq) + H₂ (g)
• What is produced when magnesium reacts with steam?

  • Bright white light and magnesium oxide
• What is the equation for magnesium reacting with steam?

  Mg(s) + H₂O(g) → MgO(s) + H₂(g)
• What does the oxidation state of hydrogen become when magnesium reacts with hot steam?

  Hydrogen is reduced to +1
• What happens to metal hydroxides in water?

  • They can dissolve to produce alkaline solutions
• What is the dissociation equation for barium hydroxide?

  Ba(OH)₂ → Ba²⁺ + 2OH⁻
• What is the trend in solubility of group 2 hydroxides?

  • Solubility increases down group 2
• What is the trend in solubility of group 2 sulfates?

  • Solubility decreases down group 2
• What factors affect whether a substance dissolves?

  Energy required to break interactions vs released
• Why do group 2 hydroxides form more alkaline solutions down the group?

  • Higher concentration of OH⁻ ions
• What is magnesium hydroxide used for?

  As an antacid for indigestion
• What is calcium hydroxide used for?

  To regulate pH of soil
• What happens when barium sulfate is formed?

  It is an insoluble white precipitate
• What is the basis of the sulfate ion test?

  Add BaCl₂ to form a white precipitate
• What is the equation for the sulfate ion test?

  Ba²⁺ + SO₄²⁻ → BaSO₄ (s)
• What is the observation when barium ions are added to sulfate ions?

  White precipitate of BaSO₄ forms
• Why is it important to remove carbonate ions before the sulfate test?

  To avoid false positives from BaCO₃
• What is the test for carbonate ions?

  Add acid to produce bubbles
• What is the equation for the carbonate test?

  2H⁺ + CO₃²⁻ → CO₂ (g) + H₂O
• What happens when bubbles of gas stop during the carbonate test?

  It indicates carbonate ions are depleted
• What is the order of tests for carbonate and sulfate ions?

  1. Carbonate test
  2. Sulfate test
• How is barium sulfate used in medical imaging?

  It shows up on X-rays of the digestive tract
• What is the reaction of magnesium with titanium tetrachloride, to produce Titanium?

  2Mg + TiCl₄ → Ti + 2MgCl₂
• What are the properties of titanium produced from magnesium and titanium tetrachloride?

  • Strong
  • Light metal
• When do you move from the Carbonate test too the Sulfate test?

  After effervescence stops
• What is the topic covered in the video?

  Group 2 topic within unit 2 specification
• What are the alkaline earth metals?

  They are group 2 elements in the periodic table
• What charge do metal ions from group 2 have?

  They have a two plus charge
• How do group 2 metals react with water?

  They react to form hydroxides and hydrogen
• What is the general reaction of a group 2 metal with water?

  M + H2O → MOH + H2
• What happens to the oxidation state of group 2 metals when they react with water?

  The oxidation state increases from 0 to +2