Question

What is the electron configuration of the oxide ion (

O^2 -)?
a) 1s ^2 2s^ 2 2p ^2
b) 1s ^2 2s^ 2
c) 1s ^2 2s^ 2 2P^6
d) 1s ^2 2s^ 2 2P^4

Answer 1

The electron configuration of the oxide ion (O2-) is 1s2 2s2 2p6, which fully fills the second shell and matches the noble gas neon.

Step-by-step explanation:

The electron configuration of the oxide ion (O2-) is 1s22s22p6. The oxygen atom normally has the electron configuration of 1s22s22p4, with six valence electrons. Oxygen gains two additional electrons when it forms an oxide ion, giving it a configuration similar to that of the noble gas neon. This results in a completely filled second shell, which is at a lower energy state and more stable, representing the electron configuration of the O2- ion.