Final answer:
The electron configuration of the oxide ion (O²−) is 1s²2s²2p⁶, which results from a neutral oxygen atom gaining two electrons to fill its 2p orbital, mirroring the electron configuration of neon.
Step-by-step explanation:
The electron configuration of the oxide ion (O²−) is represented by which of the following options: a) 1s²2s²2p² b) 1s²2s²2p⁴ c) 1s²2s² d) 1s²2s²2p⁶. The correct electron configuration for the oxide ion is d) 1s²2s²2p⁶. This is because an O²− ion gains two electrons compared to a neutral oxygen atom, resulting in a filled 2p orbital.
The electron configuration of a neutral oxygen atom is 1s²2s²2p⁴. When it gains two electrons to form the O²− ion, the additional electrons fill up the 2p orbital, resulting in the configuration 1s²2s²2p⁶, which is the same as that of the noble gas neon. This gives the oxide ion a full valence shell, rendering it more stable.