What is being taught lesson by lesson:
- The ions of metal and non-metal atoms. It is really useful at this time to learn some of the most common ions and their charges.
- Describing how an ionic bond is formed, drawing a depiction and calculating the ratio of ions in an ionic compound.
- Covalent bonding.
- Metallic bonding and monatomic substances.
- States of matter and their transitions including graphs.
- Properties of ionic substances.
- Properties of covalent substances (simple molecules).
- Giant covalent structures and the allotropes of carbon.
- Alloys and nano-particles.
- Polymers – look at their properties.
Key Terms for this topic (Tier 3 vocabulary)
Ions – charges – electrostatic attraction – lattice – free moving ions – covalent – intermolecular forces – simple molecules – conductivity – polymers – allotrope – diamond – graphite – fullerene – graphene – delocalised – sublimation.
Bonding, Structure & Properties
Are you ready for your assessment in this topic? Try out this simple quiz.
What everyone needs to know:
Ionic bonds are formed between metals and non-metals in a compound. Covalent bonds are formed with non-metals only. Metallic bonding is present in metals and alloys. You need to explain these bonds in terms of electron transfer and sharing.
Ionic compounds have specific properties such as high melting points, they are usually soluble and only conduct electricity if they are melted or dissolved in water (as they need free moving ions to conduct). They are held together by strong electrostatic forces.
Covalent molecules are also called simple molecules. This is because despite having very strong covalent bonds between the atoms, they have very weak intermolecular forces between molecules giving them very low melting ad boiling points. You need to be able to draw dot and cross diagrams for their structures.
In metallic bonding, you need to describe the regular arrangement of ions (remember that there are no atoms in metal, they are all ions) surrounded by the delocalised electrons (sea of electrons). This explains why metals can conduct both heat and electricity.
You need to describe the properties of polymers, giant covalent structures including the allotropes of carbon and different alloys (how adding different sized atoms can change the strength etc).
Linking to these properties, you need to understand the models of solids, liquids and gases. Accurately sue state symbols.
Extra topics needed for the Higher papers:
For this, you need to be able to explain the limitations of the models we use for solids liquids and gases, for example, there are no forces between the molecules in this model and that the particles are shown as perfect spheres that do not change shape at all.