3.1.6.1 Chemical equilibria and Le Chatelier's principle

The trends in atomic radius, first ionisation energy and

melting point of the elements Mg–Ba

Students should be able to:

• explain the trends in atomic radius and first ionisation energy

• explain the melting point of the elements in terms of their structure and bonding.

The reactions of the elements Mg–Ba with water.

The use of magnesium in the extraction of titanium from TiCl4

The relative solubilities of the hydroxides of the elements Mg–Ba in water.

Mg(OH)2 is sparingly soluble.

The use of Mg(OH)2 in medicine and of Ca(OH)2 in agriculture.

The use of CaO or CaCO3 to remove SO2 from flue gases.

The relative solubilities of the sulfates of the elements Mg–Ba in water.

BaSO4 is insoluble.

The use of acidified BaCl2 solution to test for sulfate ions.

The use of BaSO4 in medicine.

Students should be able to:

• explain why BaCl2 solution is used to test for sulfate