The electronic configuration of ions refers to representation of electrons in the various energy shells and subshells more collectively called as orbits of the atom.

[a] H^- ion

The electronic configuration of H atom is 1s¹. [Atomic number = 1]

∴ Electronic configuration of H^- = 1s²

[b] Na⁺ ion

The electronic configuration of Na atom is 1s² 2s² 2p⁶ 3s¹. [Atomic number = 11]

∴ Electronic configuration of Na⁺ = 1s₂ 2s² 2p⁶3s⁰ Or 1s² 2s² 2p⁶

[c] O^2- ion

The electronic configuration of 0 atom is 1s² 2s² 2p⁴. [Atomic number = 8]

∴ Electronic configuration of O^2- ion = 1s² 2s² p⁶

[d] F^- ion

The electronic configuration of F atom is 1s² 2s² 2p⁵. [Atomic number = 9]

∴ Electron configuration of F^- ion = 1s² 2s² 2p⁶