Classification Of Elements And Periodicity In Properties

  • Question
    CBSEENCH11008104

    The correct sequence which shows decreasing order of the ionic radii of the elements is

    • Al3+ > Mg2+ > Na+ > F- > O2-

    • Na+ > Mg2+ > Al3+ > O2- > F-

    • Na+ > F- > Mg2+ > O2- > Al3+

    • O2- >F- > Na+ > Mg2+ >Al3+

    Solution

    D.

    O2- >F- > Na+ > Mg2+ >Al3+

    O2-, F-, Na+, Mg2+,Al3+ are isoelectronic species (10 electrons each)
    Cation having a positive charge is smaller in size than neutral atom whereas anion having a negative charge is larger in size than neutral atom.

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