Briefly describe the nature of three types of intramolecular bonding and two types of intermolecular bonding (drawings encouraged)

The terms intra- and intermolecular bonding refers to bonds formed between atoms within molecules and between two or more molecules respectively. Intramolecular bonding would be: ionic, covalent and metallic bonding. Whereas intermolecular bonding could include: hydrogen bonding and Van de Waals interactions. Ionic bonding involves the donation of one or more electrons from one atom to another creating a negative ion and a positive ion (anion and cation respectively). This typically occurs between highly electropositive and electronegative elements such sodium (Na) and chlorine (Cl) to create table salt, sodium chloride (NaCl). Covalent bonding involves two atoms ‘sharing’ a pair of electrons. It is the most ubiquitous bond in organic synthetic chemistry and usually occurs between non-metals of similar electronegativity, for example, in di-atomic halogen molecules (F2, Cl2, Br2) and the C-C and C-H bonds in an alkane. Metallic bonding, as the name suggests, occurs in pure metal compounds and involves the metal cations existing arranged in a lattice amidst a sea of delocalised electrons. This is why metals can conduct electricity because the electrons are able to ‘move’ across the material. Hydrogen bonding occurs when a delta(+) hydrogen (such as an alcohol O-H) on one molecule and a lone pair of electrons in a functional group on another molecule (perhaps on the oxygen in another alcohol O-H) are close enough that there is an electrostatic attraction. Hydrogen bonding is a very important form of intermolecular bonding to consider and is responsible for water’s unusually high boiling point and the fact it expands when it freezes. Van de Waals interactions refers to the attraction between instantaneous dipoles in atoms and molecules. Orbitals describe the electron density in molecules and at any instant that electron density may be asymmetrical creating an instantaneous dipole. Van de Waals interactions are very weak and short range so molecules typically have to be very close to one another to ‘feel’ this interaction.