Predicting Reactivity

• Predicting Reactivity:

  • Using some of the patterns of reactivity in the Periodic Table we can predict what properties an element may have 
• Predicting Reactivity:

  • Key patterns include:
  • Elements in Group 1 and 2 are highly reactive 
  • Metals in Group 1 and 2 get more reactive as you go down
  • Metals form ionic compounds with reactive non metals
  • Non- metals in Group 7 get less reactive as you go down 
  • Group 0 elements are unreactive
• Diagram: here...

  
• Comparison of Transition Metals and Group 1 Properties:

  • There are also some key differences between the reactivity of transition metals and Group 1 metals
  • All of the group 1 metals form ions with a +1 charge while the transition metals can form ions with variable charges
  • For example iron can form an Fe2+ ion or an Fe3+ ion
• Comparison of Transition Metals and Group 1 Properties:

  • The transition metals are much harder, stronger and denser than the group 1 metals, which are very soft and light
  • They have much higher melting points e.g. titanium melts at 1,688 ºC whereas potassium melts at only 63.5 ºC, not far off the average cup of tea!
  • The transition metals are much less reactive than the group 1 metals
  • The alkali metals react with water, oxygen and halogens while the transition metals either react very slowly or do not react at all
• Comparison of Transition Metals and Group 1 Properties:

  • A classic example of this is the reaction with oxygen
  • A Group 1 metal will tarnish in the presence of oxygen as a metal oxide is formed
  • When cut with a knife, the shiny appearance of the metal disappears in seconds as it is covered by the dull metal oxide
  • Iron on the other hand can take several weeks to react with oxygen to form iron oxide (rust) and requires the presence of water