Question

Why do the boiling points of the noble gases increase in order\(He < Ne < Ar < Kr < Xe\)?

Short answer

The order of the London force and the order of a boiling point re similar.

Step-by-step solution

Definition of Boiling Point

The temperature at which the vapour pressure matches the standard sea-level air pressure is known as the normal boiling point of a liquid; the boiling point of a liquid varies depending on the applied pressure.

Explanation for the increase in the boiling points

The London force increases as the number of electrons increases. Therefore, the order of London force is \({\rm{He}} < {\rm{Ne}} < {\rm{Ar}} < {\rm{Kr}} < {\rm{Xe}}{\rm{.}}\)

Now, as the London’s force increases, the temperature required to match the vapor pressure of a liquid to external pressure also increases. Therefore, with an increase in the London force, there is also an increase in the boiling point.

Therefore, the order of the London force and the order of a boiling point are similar.