Predicting Structure and Physical Properties

Understanding the fundamental link between structure, bonding, and physical and chemical properties is essential.
Covalent, ionic, metallic and van der Waals bonding types presents different structures and related properties.
Covalent bonds are typically found in individual molecules or networks of covalent bonds, leading to differing physical properties such as incipiently weak forces between molecules, but strong bonds within them.
Ionic bonds result in structures featuring oppositely charged ions arranged in a repeating lattice structure. The resulting substances tend to be rigid and brittle, with high melting and boiling points due to the strong electrostatic forces of attraction between the ions.
Metallic bonds involve a ‘sea’ of delocalised electrons, which gives metals their notable properties such as high thermal and electrical conductivity, malleability, and ductility.
Van der Waals forces or London dispersion forces, are weak intermolecular attractions resulting from constantly changing electron clouds. Higher mass and size equals increased Van der Waals forces.
Polar molecules, having a positive and negative end, have dipole-dipole attractions adding to the Van der Waals forces.
Hydrogen bonding, a strong type of intermolecular force, occurs when a hydrogen atom in a molecule is attracted to a lone pair of electrons on a highly electronegative atom (typically nitrogen, oxygen, or fluorine) in another molecule.
Understanding the impact of shape on molecules is fundamental when predicting physical properties and reactivity. This is especially important in organic compounds, where structural isomerism can result in substantially different properties.
The number of electron pairs surrounding an atom will determine its shape based on the theory of Valence Shell Electron Pair Repulsion (VSEPR).
Macroscopic properties such as boiling points, melting points, hardness and electrical conductivity can often be predicted based on the type and strength of forces between particles within a substance.
The ability to predict and explain these properties forms a significant portion of understanding and applying chemical knowledge.