Why does aluminium conduct electricity well? Why is oxygen a gas at room temperature? Why is diamond such a strong substance? Why does water have a higher boiling point than expected? Why are the noble gases all gases? Why does sodium bromide have a high melting point?

Explaining bonding and its properties Describe metallic bonding as the attraction of positive ions to delocalized electrons.   Describe the following structures: giant ionic lattice, giant covalent lattices, giant metallic lattices and simple molecular lattices (eg ice) Interpret physical properties from different bonding types above: Melting Points/Boiling Points Electrical conductivity Solubility

Homework 1) What is the different between permanent dipole interactions and Van der Waals forces? 2) Why does xenon have a higher boiling point than helium? 3) Explain why symmetric molecules don’t have dipoles. 4) What type of bonding are dipole-dipole interactions similar to? Page 35

Topics so far Atomic theories and Ar and Mr Mole calculations and equations Acids, alkalis and titrations Oxidation and reduction Electronic structure and ionisation energies Ionic, covalent and metallic bonding Shapes of compounds Electronegativity and dipoles Hydrogen bonding and Van der Waals forces

Metallic Bonding Metallic bonded materials have positive metal ions in a sea of delocalised electrons.

Explaining properties The way substances bond determine exactly how the substance acts. e.g. Copper has a high melting point, because the positive Cu2+ ions are strongly attracted to the negative delocalised electrons (2 per atom). Aluminium is a good thermal conductor because the delocalised electrons can pass kinetic energy to each other.

Properties you need to explain: 1) Structure (simple molecular or giant lattice?) 2) Melting and Boiling Points (what attraction is there?) 3) Solubility (is the substance polar?) 4) Thermal and electrical conductivity (delocalised electrons)

Answer the questions at the bottom of page 27, 29 and 31

Compound Shape Revision

Explaining bonding and its properties Describe metallic bonding as the attraction of positive ions to delocalized electrons.   Describe the following structures: giant ionic lattice, giant covalent lattices, giant metallic lattices and simple molecular lattices (eg ice) Interpret physical properties from different bonding types above: Melting Points/Boiling Points Electrical conductivity Solubility