Older MCQs might not have the typical A, B, C,
D
choices. They
have choices 1, 2, 3, and a combination of them is the answer. Below is the key that maps such
combinations to the answer.
A
1, 2 and 3 are correct
B
1 and 2 only are correct
C
2 and 3 only are correct
D
1 only is correct
(a) describe van der Waals’ forces as the intermolecular forces between molecular entities other than those due to bond formation, and use the term van der Waals’ forces as a generic term to describe all intermolecular forces (b) describe the types of van der Waals’ forces: • instantaneous dipole–induced dipole (id-id) forces, also called London dispersion forces • permanent dipole–permanent dipole (pd-pd) forces, including hydrogen bonding (c) describe hydrogen bonding and understand that hydrogen bonding is a special case of permanent dipole–permanent dipole forces between molecules where hydrogen is bonded to a highly electronegative atom
describe addition polymerisation as exemplified by poly(ethene) and poly(chloroethene), PVC
(a) describe covalent bonds in terms of orbital overlap giving σ and π bonds: - σ bonds are formed by direct overlap of orbitals between the bonding atoms - π bonds are formed by the sideways overlap of adjacent p orbitals above and below the σ bond (b) describe how the σ and π bonds form in molecules including H\(_2\), C\(_2\)H\(_6\), C\(_2\)H\(_4\), HCN and N\(_2\) (c) use the concept of hybridisation to describe sp, sp\(^2\) and sp\(^3\) orbitals
