Group 2 Unit 1 Chemistry

CAPE Chemistry Unit 1: Module 3 Chemistry of the elementsRefer to Chapter 14 of Chemistry for Cape by Susan Maraj

GROUP-2

INDEX

2.1 Explain the variations in properties of the elements in terms of structure and bonding

2.2 Describe the reactions of the elements with oxygen, water and dilute acids

2.3 Explain the variation in the solubility of the sulphates

2.4 Explain the variation of the thermal decomposition of the carbonates and the nitrates

2.5 Discuss the uses of some of the compounds of magnesium and calcium

2.1 Physical properties of Group 2

Physical properties of group 2

2.2 Reactions of group 2 elements

Click here for the reaction of the group elements with acid

2.3Solubility of Group 2 sulphates

The solubility of a solid (Enthalpy of a solution ) is determined by two factors : Lattice Enthalpy/Energy and the Enthalpy change of Hydration of the aqueous ionsClick here for more

VIDEO

You can conduct a lab experiment to investigate the solubility of the group 2 sulphates by mixing aqueous solutions of the Group 2 cations with H2SO4 and observing the appearance/thickness of the precipitates

2.4Thermal decompositon of carbonates

Trend in thermal stability

In the table on the left, notice that as you go down the group, the temperature to decompose the caarbonates increases. You can either say Thermal stability INCREASES DOWN THE GROUP or Thermal decomposition decreases down the group.

Image showing how the group 2 cation can polarize the carbonate ion

2.4 THERMAL DECOMPOSITON OF NITRATES

VIDEO

2.5 Uses of group 2 compounds

Calcium hydroxide

Magnesium oxide

Calcium oxide

Calcium carbonate

neutralizing acidic soil, making bleaching powder, making lime water

refractory lining in furnaces because of high m.p. and low reactivity

used to make cement and mortar, drying agent, in agriculture to counteract soil acidity

as a building material, , as a dietary supplement, as antacid, in the extraction of iron in the blast furnace

THANKS!