Chapter 8- reactivity trends

• List 3 physical properties of group 2 metals

  High melting and boiling points

  Form colourless compounds

  Low density metals
• Does reactivity increase or decrease going down group 2 and why?

  It increases as there is a larger atomic radius and more electron shielding so less electrostatic attraction between nucleus and outer shell electrons so outer electrons are lost more easily
• What happens to first ionisation energy going down group 2 and why?

  It decreases as there is increased electron shielding and an increased atomic radius so weaker force between outer electron and nucleus so less energy needed to remove electron
• What type of reaction is between group 3 and oxygen?

  Redox
• Equation for the reaction of calcium and oxygen

  2Ca (s) + O2 (g) = 2CaO (s)
• What are the products when group 2 react with water?

  Hydroxide and hydrogen gas
• What are the products when a group 2 element reacts with a dilute acid?

  Salt and hydrogen gas
• An equation for reaction of Ca and HCl

  Ca (s) + HCl (aq) = CaCl2 (s) + H2 (g)
• What forms when group 2 oxides react with water?

  Metal hydroxide
• An equation between a group 2 oxide and water

  MO (s) + H2O (l) = M(OH)2 (aq)
• Explain the solubility of group 2 hydroxides

  Increases down the group so the remaining solutions contain more OH- and are more alkaline
• What is Ca(OH)2 used for

  In agriculture to increase the pH of acidic soils
• State and explain the trend in alkalinity of the solution formed when group 2 oxides are added to water

  Group 2 oxides react with water forming the metal hydroxide. Hydroxide ions in solution cause alkalinity. Down group 2 the solubility of the metal hydroxide increases increasing the pH and alkalinity.
• Why are group 2 elements reducing agents?

  They add electrons to other species