The correct answer is: C. Na+ > O2- > N3- > F-
Ionic radius is the radius of an ion, which is defined as half the distance between the nuclei of two adjacent ions of the same charge. The ionic radius of an ion is inversely proportional to the effective nuclear charge of the ion. The effective nuclear charge is the net positive charge experienced by an electron in an atom or ion. It is calculated by subtracting the shielding effect of the inner electrons from the nuclear charge.
The effective nuclear charge of an ion increases as the atomic number increases. This is because the number of protons in the nucleus increases, while the number of electrons remains the same. As a result, the electrons are more tightly bound to the nucleus and the ionic radius decreases.
In the case of N3-, O2-, F-, and Na+, the atomic numbers are 7, 8, 9, and 11, respectively. Therefore, the effective nuclear charge of Na+ is the highest, followed by O2-, F-, and N3-. This means that the ionic radius of Na+ is the smallest, followed by O2-, F-, and N3-.
The ionic radii of the ions can be arranged in the following order:
Na+ > O2- > F- > N3-