Moderate

In the isoelectronic species, the ionic radii of N3- ,O2- and F- are respectively given by:

Correct answer: C. 1.71 Å, 1.40 Å, 1.36 Å

  • A. 1.36 Å,1.40Å, 1.71 Å
  • B. 1.36 Å, 1.71Å, 1.40Å
  • C. 1.71 Å, 1.40 Å, 1.36 Å
  • D. 1.71Å, 1.36Å, 1.40Å

Explanation

N³⁻, O²⁻, and F⁻ are isoelectronic (all have 10 electrons). For isoelectronic species, the ionic radius decreases as the nuclear charge (atomic number) increases. Since the order of atomic numbers is N < O < F, the order of ionic radii is N³⁻ > O²⁻ > F⁻, which corresponds to the decreasing values 1.71 > 1.40 > 1.36.

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About Periodic Properties and Trends

Periodic properties arise from electron configuration and effective nuclear charge, producing trends in atomic and ionic radius, ionization energy, electron affinity, electronegativity, metallic character and reactivity. Comparisons run across periods and down groups, with attention to common exceptions. The topic also relates these trends to the behavior of s-block and p-block elements.

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