Answer:
B. [He] 2s²2p4
Explanation:
The noble gas notation for oxygen is derived from its electron configuration. Oxygen's standard electron configuration is 1s²2s²2p⁴. To obtain the noble gas notation, we reference the nearest noble gas with a lower atomic number, which in this case is helium (He), and then continue from there to describe the remaining electrons. So, the noble gas notation for oxygen becomes [He] 2s²2p⁴.
If oxygen were to gain two electrons to form the oxide anion (O²⁻), it would then have a full octet matching the electron configuration of neon (Ne), which is a noble gas. The resulting electron configuration for O²⁻ would then be [Ne] 3s²3p⁶, reflecting the stable electron arrangement of a noble gas.
