The vander waals radii of O, N, Cl, F and Ne increase in the order

$\mathrm{Radius}\propto \frac{1}{{\mathrm{Z}}_{\mathrm{eff}.}}$

• As the Zeff​ increase in a period for left to right direction so the radius decreases.
   
• But in the case of Nobel gases, the van der Waal's radius is much larger than other elements. This is because of the more electron-electron repulsion.
   
• In a group radious increase down the group.

So the order is, F<Cl<O<N<Ne