IB Chemistry S2.1 Notes

In this topic, you will explore the types of bonds within molecules, called intramolecular bonds (aka. interatomic bonds), and the bonds between molecules, called intermolecular bonds (aka. intermolecular forces).

There are three intramolecular bond types you need to be aware of. These are shown below in order of decreasing strength:

1. Covalent bonding (strongest)
2. Ionic bonding
3. Metallic bonding (weakest)

When considering covalent compounds (formed from covalent intramolecular bonds), there are also three intermolecular bonds/forces you need to be aware of. These are shown below in order of decreasing strength:

1. Hydrogen bonds (strongest)
2. Dipole-dipole forces
3. London dispersion forces (weakest)

You may have heard ionic bonds are stronger than covalent, and whilst there are certain situations in which this can be the case, it depends on the environment in which the ionic species is found (solvated, vacuum, etc.) and the IB does not recognise this. Therefore, for your IB exam you should focus on the intramolecular ranking listed above.