Question

In which of the following pairs, the ions are iso-electronic?

(i) \[\ce{Na^{+}, Mg^{2+}}\]

(ii) \[\ce{Al3^{+}, O-}\]

(iii) \[\ce{Na+ , O2-}\]

(iv) \[\ce{N3-, Cl-}\]

Answer 1

(i) \[\ce{Na^{+}, Mg^{2+}}\]

(iii) \[\ce{Na+ , O2-}\]

Explanation:

Isoelectronic species are those species that possess the same number of electrons.

Here both  \[\ce{Na+, Mg^{2+}}\] possess 10 electrons and both \[\ce{Na+ , O2-}\] possess 10 electrons.