In which of the following pairs the ions are isoelectronic?

Options

A. `Na^(+),Mg^(2+)`
B. `Al^(3+).O^(-)`
C. `Na^(+),O^(-)`
D. `Na^(3-),Cl^(-)`

Answer

A

Explanation

For `Na^(+)=11-1=10e^(-)`
`Mg^(2+)=12-2=10e^(-)`
Thus, they have same number of electorns.
for, ` Al^(3+)=13-3=10e^(-),O^(-)=8+ 1=9e^(-)`
They do not have same number of electrons
For `Na^(+)=10e^(-),O^(2-)=8+2=10e^(-)`
They have same number of electrons.
For `N^(3-)=7+3=10e^(-).Cl^(-)=17+1=18e^(-)`
They do not have same number of electrons
Thus, `Na^(+)` is isolectronic with `Mg^(2+)` and `O^(2-)`