Which element has an ion with a radius that is larger than its atomic radius
a)k
b)cr
c)zn
d) cl

d) Chlorine

Explanation:

when an atom form ion its atomic radius changed from neutral atomic radius.

if the atom form cation its atomic radius is smaller than neutral atomic radius.

If atom form anion its anionic radius is larger than the neutral atomic radius.

The reason is that when electron is remove energy shell deduced so cation get smaller ionic radii while in case of anion electron is added and size increase.

In given list of elements potassium, zinc and chromium form cation while chlorine form anion.

That's why its ionic radius will larger than atomic radius.