Question

Why do boiling points of noble gases increase in the order of He to Radon

Answer 1

Dear Student,

Weak intermolecular forces of attraction like Vander Waal forces are present between the molecules of noble gases. Strength of weak intermolecular forces increases with the increase of size of atom.
The increasing order of size of atom from He to Rn is He<Ne<Ar<Kr<Xe<Rn
As size of atom is increasing from He to Rn, therefore weak intermolecular forces of attraction are increasing and as a result, boiling point increases.