• # question_answer 51) In the following Questions only one option is correct. Consider the isoelectronic species, $N{{a}^{+}},M{{g}^{2+}},{{F}^{-}}$ and ${{O}^{2-}}$. The correct order of increasing length of their radii is : (a)${{F}^{-}}<{{O}^{2-}}<M{{g}^{2+}}<N{{a}^{+}}$                                        (b) $M{{g}^{2+}}<N{{a}^{+}}<{{F}^{-}}<{{O}^{2-}}$ (c) ${{O}^{2-}}<{{F}^{-}}<N{{a}^{+}}<M{{g}^{2+}}$                                        (d) ${{O}^{2-}}<{{F}^{-}}<M{{g}^{2+}}<N{{a}^{+}}$

(b) In isoelectronic species, the ionic radii decrease as the nuclear charge increases, i.e., atomic number increases. $M{{g}^{2+}}<N{{a}^{+}}<{{F}^{-}}<{{O}^{2-}}$                            Z =12        11        9         8