The ionic radii of N^3-, O^2-, F^- and Na⁺ follows the order

Give the solution plz

When a neutral atom gains or loses an electron, creating an anion or cation, the atom's radius increases or decreases.

cations are smaller than their respective neutral atoms.
anions are bigger than their respective neutral atoms.

why? because cations lose electrons and so decrease electron-electron shielding so protons are better able to pull the remains electrons towards the nucleus. more electrons the smaller the radius.

anions gain electrons so per gain an additional electron occupies an outer orbital > there is an increased electron-electron repulsion (And hence shielding) which pushes electrons further apart.

also the electrons outnumber the protons in the nucleus because we added electrons and in an neutral atom proton number = no. of electrons. Therefore, the protons in the ion, cannot pull the extra electrons as tightly towards the nucleus as they could in the neutral atom.