Question

Anion ${\mathrm{O}}^{-}$ is isoelectronic with_______.

Answer 1

Anion ${\mathrm{O}}^{-}$ is isoelectronic with ${\mathrm{N}}^{2-}$

• Isoelectronic species: Atoms or ions with the same number of electrons are classified as isoelectronic species.
• The number of electrons in isoelectronic species is the same but the elements are different.
• The atomic number of oxygen is 8, so it has a total of 8 electrons.
• In the anion ${\mathrm{O}}^{-}$ = 8 + 1 = 9 electrons (As anion is formed by the gain of electrons and one electron is gained as there is one negative charge)

The atomic number of nitrogen is 7, so it has a total of 7 electrons.

• In anion ${\mathrm{N}}^{2-}$ = 7 + 2 = 9 electrons.

Therefore, anion, ${\mathrm{O}}^{-}$ is isoelectronic with ${\mathrm{N}}^{2-}$