In Lithium + Oxygen, why is the valence electrons for Oxygen 1s2 2s2 2p6 and not 1s2 2s2 2p4 ?

Atoms react with each other in order to achieve stable electron configurations. with all the electrons with opposite spin paired up. Oxygen requires only 2 electrons to achieve the stable noble gas structure. Each Li atom loses 1 electron and it now has the same structure as He...