The Periodic Table: chemical periodicity

You will be able to

• Describe qualitatively the variation in atomic radius, ionic radius, melting point and electrical conductivity across Period 3.
• Explain the variation in melting point in terms of metallic, giant covalent and simple molecular structure and bonding.
• Explain the variation in electrical conductivity in terms of delocalised electrons and the absence of mobile charge.

You will be able to

• Describe and write equations for the reactions of the oxides Na2O, MgO, Al2O3, SiO2, P4O10, SO2 and SO3 with water, including the likely pH of the solutions.
• Describe, explain and write equations for the acid–base behaviour of the oxides, including the amphoteric behaviour of aluminium oxide.
• Explain the variation in behaviour in terms of the oxidation number and the bonding (electronegativity difference with oxygen).