Question

Which of the following are isoelectronic?

A. K⁺¹, Na⁺¹, He
B. Mg⁺², O⁻², Kr
C. N⁻³, O⁻², Ne
D. All are equally similar

Answer 1

The correct answer is option C.

Step-by-step explanation:

Isoelectronic species are those atoms or ions which same number of electrons.But they differ in physical and chemical properties.

Atomic number of nitrogen atom is 7.

`[N]=1s^22s^22p^3`

`[N]^(3-)=1s^22s^22p^6`

Number electron in nitride ions =
`N^(3-)=10`

Atomic number of oxygen atom is 8.

`[O]=1s^22s^22p^4`

`[O]^(2-)=1s^22s^22p^6`

Number electron in oxide ions =
`O^(2-)=10`

`[Ne]=1s^22s^22p^6`

Number of electrons neon =
`Ne=10`

Hence,
`N^(3-) , O^(2-) \& Ne` are isoelectronic.