Reactions

• Elements with Oxygen

  A) 2Mg0

  B) 2CaO

  C) 2SrO

  D) 2BaO

  
• Group 1 flame tests

  Each element has a characteristically different colour when it burns

  Lithium -> RED

  Na -> ORANGE

  K -> LILAC
• Group 2 flame tests

  each element has a characteristically different colour when it burns

  Be -> no

  Mg -> white

  Ca -> red

  Sr -> red

  Ba -> green

  Ra -> too reactive to tell
• Why are different colour observed when burning different elements?

  different colours are observed because when the atoms are heated the electrons are able to move from their ground state to higher energy levels.

  returning to their ground state emits a light of a specific energy

  this energy corresponds to particular wavelengths of visible light.
• Group 2 elements with water:

  increasingly readily with water as you go down the group.

   

  Forming hydroxide and hydrogen gas

  A) Ca(OH)2 (s) + H2

  B) Sr(OH)2 (s) + H2 (g)

  C) Ba(OH)2 (s) + H2 (g)

  
• Exceptions with magnesium and water

  magnesium reacts readily with steam but very slowly with water

   

  With steam, forms magnesium oxide and hydrogen gas

   

  With water, forms magnesium hydroxide and hydrogen gas
• Elements with dilute acids

  when reacting with dilute acids, forms corresponding salt along with hydrogen gas

  A) MgCL2 + H2

  B) Ca(NO3)2 +H2

  C) SrCL2 + H2

  D) BaSO4 + H2

  
• The reaction with sulphuric acid in group 2 elements will be increasingly slow from Calcium to Barium due to the formation of the insoluble sulphate salt coating the metal and stopping the reaction.
• Oxides with water:

  react with water to form hydroxide forms

   

  general equation

  M0 + H20 -> M(OH)2

  A) Mg(OH)2

  B) Ca(OH)2

  C) Sr(OH)2

  D) Ba(OH)2

  
• Oxides with dilute acids:

  metal oxides + dilute acids = corresponding salt and water

  A) MgCL2 + H2O

  B) Ca(NO3)2 + H20

  C) SrCL2 + H2O

  D) BaSO4 +H2O

  
• Reaction with sulphuric acid will be increasingly ineffective from Ca -> Ba due to the formation of the insoluble sulphate salt coating the oxide and stopping the reaction.
• Hydroxides with water and dilute acids:

  NO reaction between group 2 hydroxides and water

   

  usual neutralisation

  A) MgCL2 + 2H2O

  B) Ca(NO3)2 + 2H20

  C) SrCL2 + 2H2O

  D) BaSO4 +2H2O

  
• Carbonates with water and dilute acids:

  NO reaction between group 2 carbonates and water

   

  because they are insoluble

  Usual neutralisation forming carbon dioxide

  A) MgCL2 + CO2 +H20

  B) Ca(NO3)2 + CO2 +H20

  C) SrCL2 + CO2 +H20

  D) Ba(NO3)2 + CO2 +H20

  
• Sulphuric acid only reacts successfully with magnesium carbonate due to insoluble nature of sulphates.
• What colour does Ra burn when burnt ?

  too reactive too tell