Group 2 elements:  Redox eactions:

The Group 2 elements:

Physical properties:

Electronic configuration:

Reactivity of Group 2 elements:

Practical

M M2+ + 2e-

 

Oxidation

            Is

            Loss of electrons

 

            Reduction

            Is

            Gain of electrons

Reaction with oxygen

Metal              +          Oxygen                 Metal oxide

Calcium + Oxygen Calcium oxide    
2Ca(s) + O2(g) 2CaO(s)    

 

Element 2Ca(s) + O2(g) 2CaO(s) Change in Ox No Redox
Up Down
Ca 0       +2 2   Ox
O     0   - 2   2 Red

 

Reaction with water

 

Metal              +          Water                     Metal hydroxide         +          Hydrogen

Calcium + Water Calcium hydroxide + Hydrogen
Ca(s) + 2H2O(l) Ca(OH)2(aq) + H2(g)

 

Element Ca(s) + 2H2O(l) Ca(OH)2(aq) + H2(g) Change in Ox No Redox
Up Down
Ca 0       +2     2   Ox
H     +1   (+1)   0   1 Red
O     -2   -2   - - - -

Questions 1 - 2  P89

 

Group 2 compounds:  reactions

Group 2 oxides and hydroxides:

MgO(s) + 2HCl(aq) MgCl2(aq) + H2O(l)
Ca(OH)(s) + 2HCl(aq) CaCl2(aq) + 2H2O(l)

1)  Group 2 oxides:

MgO(s) + H2O(l) Mg(OH)2(aq)    

2)  Group 2 hydroxides:

Ca(OH)2(s) + aq Ca2+(aq) + 2OH-(aq
  • The solubility of the Group 2 hydroxides increases as you go down the Group.
  • This means that as you go down Group 2 more hydroxide ions are formed (for the same amounts).
  • This means that as you go down Group 2 they become more alkaline.

3)  Group 2 carbonates:

            Is the breaking down of a chemical substance with heat into at least 2 chemical substances

MgCO3(s) MgO(s) + CO2(g)    
  • As you go down Group 2, the carbonates become harder to decompose.

Properties of Group 2 elements and their compounds:

Reactions of calcium and its compounds (or any Group 2 element / compound)

 

Uses of Group 2 hydroxides:

1)  Calcium hydroxide

Ca(OH)2(s) + 2HCl(aq) CaCl2(aq) + 2H2O(l)

 

 

2)  Magnesium hydroxide

Mg(OH)2(s) + 2HCl(aq) MgCl2(aq) + 2H2O(l)

 

Group 2

 

 Questions 1 - 2  P91  /  4, 9, 11, and 12  P97  /  4  P98