question_answer 21)

What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the following atoms or ions: (i) \[{{F}^{-}}\] (ii) \[Ar\] (iii) \[M{{g}^{2+}}\] (iv) \[R{{b}^{+}}\]  

Answer:

Ions of different elements which have same number of electrons but differ from one another in magnitude of nuclear charge are known as isoelectronic species. (i) \[{{F}^{-}}\] has 10 electrons. Isoelectronic species: \[N{{a}^{+}},M{{g}^{2+}},A{{l}^{3+}},{{N}^{3-}},{{O}^{2-}}\] (ii) Ar has 18 electrons. Isoelectronic species: \[{{K}^{+}},C{{a}^{2+}},{{P}^{3-}},{{S}^{2-}},C{{l}^{2-}}\] (iii) \[M{{g}^{2+}}\] has 10 electrons. Isoelectronic species: \[N{{a}^{+}},A{{l}^{3+}},{{N}^{3-}},{{O}^{2-}},{{F}^{-}}\] (iv) \[R{{b}^{+}}\] has 36 electrons. Isoelectronic species: \[S{{r}^{2+}},Kr,B{{r}^{-}}S{{e}^{2-}},A{{s}^{3-}}\]