3.1.2 - group 2

Created by

Katie Hine

Cards (24)

The common name given to group 2 metals is alkaline earth metals
The most reactive metal of group 2 is barium
The least reactive element in group 2 is beryllium
The highest energy electrons of group 2 are in the s orbital
Group 2 elements take part in redox reactions when they react with oxygen
Group 2 metals react with oxygen to form metal oxides with the general equation
metal + oxygen —> metal oxide
Calcium reacts with oxygen:
2Ca (s) + O2 (g) —> 2CaO (s)
group 2 elements react with water in a redox reaction to form a metal hydroxide and a hydrogen gas with general equation
metal + water —> metal hydroxide + hydrogen gas
Beryllium doesnt react with water
Magnesium reacts very slowly with water
Barium reacts with water:
Ba (s) + 2H2O (l) —> Ba(OH)2 (aq) + H2 (g)
In a redox reaction of group 2 metals and water the metal is oxidised and one hydrogen atom from each water is reduced
Calcium reacts with hydrochloric acid:
Ca (s) + 2HCl (aq) —> CaCl2 (s) + H2 (g)
When group 2 oxides react with water they form a metal hydroxide
calcium oxide reacts with water :
CaO (s) + H2O (l) —> Ca(OH)2 (aq)
Beryllium oxide is insoluble in water
Calcium hydroxide is used to neutralise soil.
Ca(OH)2 (aq) + 2HCl (aq) —> 2H2O (l) + CaCl2 (aq)
Magnesium hydroxide and calcium carbonate are used as an antacid to treat indigestion, heartburn.
What is used to treat indegestion?
magnesium hydroxide and calcium carbonate
Calcium carbonate is present in limestone and marble and is used in building construction
The drawback of using calcium carbonate in construction is that group 2 elements react with acids
When CaCO3 (limestone) is heated it undergoes thermal decomposition into CaO (quick-lime) and CO2.
the CaO (quick lime) then turns into Ca(OH)2 (limewater) when in the presence of water.
finally, when CO2 is added it returns to CaCO3 (limestone) to complete the calcium cycle
Ca(OH)2 in the solid state is known as slaked lime
Ca(OH)2 in the aqueous state is known as limewater