Question

1. Considering only ions with charges of +1, +2, -1 and -2, or neutral atoms, give the symbols for 4 species that are isoelectronic with the sulfide ion, S2-.

2. Considering only ions with charges of +1, +2, -1 and -2, or neutral atoms, give the symbols for 4 species that are isoelectronic with Ar.

Answer 1

1. $S^{2-}=1s^22s^22p^63s^23p^6$ Sulphide ion has 18 electrons. Thus, it's isoelectronic species are : $Cl^-$ (chloride ion), $Ar$ (neutral Argon atom), $K^+$ (Potassium ion) and $Ca^{2+}$ (Calcium ion).
2. $Ar=1s^22s^22p^63s^23p^6$ Argon has 18 electrons. Thus it's isoelectronic species are : $Cl^-$ (Chloride ion), $S^{2-}$ (Sulpide ion), $K^+$ (Potassium ion) and $Ca^{2+}$ (Calcium ion).