Arrange the following in increasing order of ionic radii?

C^4-, N³, F^-, O²⁻

CONCEPT:

Ionic Radii

• The ionic radius is the measure of an atom's ion in a crystal lattice. It is half the distance between two ions that are barely touching each other.
• The size of an ion is affected by its charge. As the number of electrons increases (for anions), the ion becomes larger. Conversely, as the number of electrons decreases (for cations), the ion becomes smaller.

EXPLANATION:

•  C4- :
  • With the lowest nuclear charge ( Z = 6 ), C4-  has the largest ionic radius in this series.
• N3- :
  • Nitrogen ( Z = 7 ) has a slightly higher nuclear charge than carbon, so N3- has a smaller ionic radius than C4-  .
• O2- :
  • Oxygen ( Z = 8 ) has a higher nuclear charge than nitrogen, so O2-  has a smaller ionic radius than N3- .
• F- :
  • Fluorine ( Z = 9 ) has the highest nuclear charge in this series, so F^- has the smallest ionic radius.

Increasing Order of Ionic Radii: F- < O2- < N3- < C4- .