🧪 Chemistry · Classification of Elements and Periodicity in Properties · NEET & JEE

The increasing order of ionic radius for the isoelectronic species Na+, Mg2+, F- and O2- is:

Answer: Mg 2+ + - 2-.

A O2- < F- < Na+ < Mg2+
B Na+ < Mg2+ < F- < O2-
C F- < O2- < Na+ < Mg2+
D Mg2+ < Na+ < F- < O2-

Correct answer: D. Mg2+ < Na+ < F- < O2-

Explanation: For isoelectronic species, the higher the nuclear charge the smaller the radius, so size increases as Mg2+ < Na+ < F- < O2-.

The complete modern periodic table showing all 118 elements with atomic number, symbol, and atomic mass, color-coded by element category

The complete modern periodic table (118 elements). Image: Cepheus et al., Public Domain, via Wikimedia Commons.

Concept context

The periodic table organises all 118 elements by atomic number and similar properties. Study periodic trends like atomic radius, ionization energy, and electronegativity, and learn how an element's position predicts its behaviour.

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The increasing order of ionic radius for the isoelectronic species Na<sup>+</sup>, Mg<sup>2+</sup>, F<sup>-</sup> and O<sup>2-</sup> is:

Concept context

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