Summary

The reactions of the Period 3 elements with oxygen are considered. The pH of the solutions formed when the oxides react with water illustrates further trends in properties across this period. Explanations of these reactions offer opportunities to develop an in-depth understanding of how and why these reactions occur.

Specification

3.2.4 Properties of Period 3 elements and their oxides

The reactions of Na and Mg with water.

The trends in the reactions of the elements Na, Mg, Al, Si, P and S with oxygen, limited to the formation of Na2O, MgO, Al2O3, SiO2, P4O10, SO2 and SO3

The trend in the melting point of the highest oxides of the elements Na–S

The reactions of the oxides of the elements Na–S with water, limited to Na2O, MgO, Al2O3, SiO2, P4O10, SO2 and SO3, and the pH of the solutions formed.

The structures of the acids and the anions formed when P4O10, SO2 and SO3 react with water.

Students should be able to:

• explain the trend in the melting point of the oxides of the elements Na–S in terms of their structure and bonding

• explain the trends in the reactions of the oxides with water in terms of the type of bonding present in each oxide

• write equations for the reactions that occur between the oxides of the elements Na–S and given acids and bases.