Question

Name the species which is isoelectronic with ${ N }^{ 3- }$.

Answer 1

Hint: To answer this question you should know the meaning of isoelectronic. Those species which have a similar number of electrons are called isoelectronic. Now, you can easily answer this question.

Complete step by step answer:

The atomic number of N is 7, so it has 7 electrons. In ${ N }^{ 3- }$ there is a charge of more 3 electrons, that makes the total electron count equal to 10 (7+3)
To find other isoelectronic species we need species that have 10 electrons. Some examples are -
${ O }^{ 2- }$, ${ F }^{ - }$, ${ Na }^{ + }$, ${ Mg }^{ 2+ }$, ${ Al }^{ 3+ }$

The atomic number of oxygen is 8 and ${ O }^{ 2- }$ has 10 electrons.

The atomic number of fluorine is 9 and ${ F }^{ - }$ has 10 electrons.

The atomic number of sodium is 11 and ${ Na }^{ + }$ has 10 electrons.

The atomic number of magnesium is 12 and ${ Mg }^{ 2+ }$ has 10 electrons.

The atomic number of aluminum is 13 and ${ Al }^{ 3+ }$ has 10 electrons.

We can see that all the given species have the same number of electrons (10 electrons ) so, all are isoelectronic species.

Therefore, we gave examples of isoelectronic species with ${ N }^{ 3- }$.

Note: We know, the ionic radii of isoelectronic species decrease with an increase in atomic number because the magnitude of nuclear charge increases with increasing atomic number.
increasing order of radii,
${ Al }^{ 3+ }$(Z = 13) < ${ Mg }^{ 2+ }$( Z = 12 ) < ${ Na }^{ + }$ ( Z = 11) < ${ F }^{ - }$ (Z = 9) < ${ O }^{ 2- }$(Z = 8) < ${ N }^{ 3- }$ (Z = 7)