In which of the following, the van der wall’s radii is largest?
A. Ne
B. O
C. Cl
D. F

Hint: The atomic radius of a chemical element is generally used to measure the size of its atoms and represented by the mean or general distance from the centre of the nucleus to the boundary of the surrounding shells of electrons or we can say that from nuclear to outermost shell of the electrons.

Complete answer:
Atomic radius is categorized into three types of radius known by the name Van der Waals radius, ionic radius and covalent radius. Variation of atomic radii in periodic table can be explained as, the radii generally decrease along each period or we can say each row of the table i.e. from the alkali metals to the noble gases and increase down each group column.
Van Der waals radius is defined as the radius of an imaginary hard sphere known as nucleus which represents the distance of closest approach for another atom. Vander wall radius also increases with increase in the atomic number. Here we know that chlorine has the highest atomic number out of four atoms.

Hence option C is the correct answer.

Note:
The trends of the atomic radii and van der waal radii can be explained in the way that the atomic radii decrease across the periods due to the increase in atomic number which increases the effective nuclear charge towards the outermost electrons increases and atomic radius decreases. On moving down the group atomic radii increases due to increase in the number of shells.