Humber Admissions Practice Test

Which type of force is found between all atoms, regardless of their type?

1. Dipole-dipole forces

2. Metallic bonding

3. Dispersion forces

4. Intramolecular forces

The correct answer is: Dispersion forces

Dispersion forces, also known as London dispersion forces, are a type of van der Waals force that occur between all atoms and nonpolar molecules, regardless of their specific types. These forces arise due to the temporary fluctuations in electron density within molecules or atoms, which create instantaneous dipoles. These dipoles can induce further dipoles in neighboring atoms or molecules, leading to an attractive interaction. One of the key reasons dispersion forces are found universally is that all atoms possess electrons that can fluctuate in their distribution, leading to these temporary dipoles. This means that even in noble gases or nonpolar substances, where no other types of intermolecular forces (like dipole-dipole or hydrogen bonding) exist, dispersion forces play a crucial role in their interactions. In contrast, dipole-dipole forces only occur between polar molecules where permanent dipoles are present. Metallic bonding is specific to metals where electrons are delocalized, and intramolecular forces refer to the forces that hold atoms together within a molecule, not between different atoms or molecules. Therefore, among the choices provided, dispersion forces are indeed the only type of force present between all atoms.