Final answer:
An asymmetrical electron distribution creates an instantaneous dipole moment that can induce dipoles in adjacent atoms, leading to temporary attractions known as London dispersion forces, following a 1/r^6 relationship.
Step-by-step explanation:
When an atom has an asymmetrical distribution of electrons, it creates what is known as an instantaneous dipole moment. This can occur in an atom like helium, where the two electrons are usually evenly spread but can momentarily be found more on one side.
Adjacent atoms with their own instantaneous dipole moments can influence one another, resulting in the induced dipole of the second atom. The interaction between these temporary dipoles leads to a weak, temporary attractive force, described as London dispersion forces. The attractive energy due to these interactions decreases rapidly with distance, obeying a 1/r6 relationship, as shown by quantum mechanics.