Answer:
The radii of potassium is 231 pm
Step-by-step explanation:
Atomic radii trend along group:
As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.
The given elements are present in same group i.e group one,
Li 152 pm
Na 186 pm
K
Rb 244 pm
The radii of potassium must be greater than sodium and smaller than rubidium.
Thus the value must be between 186 pm - 244 pm
it means the radii of potassium is 231 pm.