IB chemistry experiment: A practical study of some group II elements (SL/HL)
Aim
To study some of the properties of the elements of group II and their compounds.
Introduction
The s-block of the periodic table contains the most reactive and, in chemical terms, the most typically
metallic elements. All the elements in group I are highly reactive, but those in group II are slightly less so
and show a rather more obvious trend in reactivity.
We will concentrate on the three elements magnesium, calcium and barium. Beryllium will not be
studied because its compounds are extremely toxic and very expensive.
Requirements and materials
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safety goggles
test tubes
stopper to fit test tubes
test tube holders
angles glass bend with bung to fit test tube
beaker ,400 ml
funnel
universal indicator solution
indicator paper
filter paper
splints
magnesium ribbon
magnesium powder
calcium granules
magnesium oxide
calcium hydroxide
barium hydroxide
hydrated magnesium chloride
hydrated calcium chloride
hydrated barium chloride
magnesium carbonate
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magnesium oxide
calcium hydroxide
barium hydroxide
hydrated magnesium chloride
hydrated calcium chloride
hydrated barium chloride
magnesium carbonate
calcium carbonate
barium carbonate
lime water
0.1 mol dm-3 solutions of:
 Mg2+ (25g Mg(NO3)2.6H2O or 20g MgCl2.6H2O
per dm-3)
 Ca2+ (25g Ca(NO3)2.6H2O or 10g anhydrous
CaCl2)
 Ba2+ (25g Ba(NO3)2.6H2O or 25g BaCl2.2H2O
per dm-3)
1.0 mol dm-3 solutions of:
 OH- (40g NaOH per dm-3)
 CO32+ (100g anhydrous Na2CO3 per dm-3)
 SO42+ (300g Na2SO4.10H2O per dm-3)
SAFETY
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Eye protection must be worn throughout this practical.
Barium and its compounds are poisonous. Handle with care and wash your hands
afterwards.
Calcium and magnesium are flammable.
Calcium, hydrated calcium chloride and solutions of hydroxides are irritants.
Hydrogen chloride gas is toxic.
Procedure
Experiment 1: Reactions of the elements with water
Put a very small piece of calcium metal into a large beaker of cold water. Identify the products.
Repeat using a small piece of clean magnesium ribbon.
Experiment 2: Acid-base character
Place a very small quantity (about 0.01g) of magnesium oxide, calcium hydroxide and barium hydroxide
in three separate test tubes.
Add 10 cm3 distilled water to each tube, stopper the tube and shake.
Add 2 drops of universal indicator solution to each tube and mix.
Experiment 3: Hydrolysis of the chlorides
Ionic chlorides dissolve in water forming simple hydrated ions. Many covalent and partly covalent
chlorides, however, are hydrolysed, giving hydrogen chloride and the oxide or hydroxide. For example,
aluminium chloride reacts vigorously with water as follows:
AlCl3
+
3H2O
 Al(OH)3 +
3HCl
The extent of the hydrolysis of the group II chlorides can be estimated by heating the hydrated chloride
and testing for hydrogen chloride gas.
Working in a fume cupboard, strongly heat about 1 cm depth of the hydrated chlorides of magnesium,
calcium and barium in separate, dry, hard test tubes. Test for the evolution of hydrogen chloride.
Experiment 4: Thermal stability of carbonates.
Strongly heat about 1 cm depth of each of the dry carbonates of magnesium, calcium and barium
separately in the apparatus shown below. Continue heating strongly for several minutes.
Remember to remove the tube from the lime water as soon as heating is stopped.
Experiment 5: Solubility of some compounds of group II elements
To investigate the solubility of Group II compounds, solutions containing the appropriate anions and
cations are mixed. Deduce the solubility.
Put 2 cm3 of a 0.1 mol dm-3 solution of each of the Group II cations under investigation (Mg2+, Ca2+,
Ba2+) in separate test tubes. Add an equal volume of a 1.0 mol dm-3 solution of hydroxide ions and mix.
Remember, do not put your thumb over the test tube when mixing. Compare precipitates.
Repeat the experiment twice, using first a 1.0 mol dm-3 solution of sulphate ions and then a 1.0 mol dm-3
solution of carbonate ions, instead of the hydroxide ions.