Multiple answers, Ion formed by Oxygen?
O2+
O2-
Oxide

Explanation:The formation of the oxide ion, O

2−

(g), from oxygen atom requires first an exothermic and then an

endothermic step as shown below:

O(g)+e

−

→O

−

(g);Δ

f

H

⊖

=−141kJmol

−1

O

−

(g)+e

−

→O

2−

(g);Δ

f

H

⊖

=+780kJmol

−1

Thus, process of formation of O

2−

 in gas phase is unfavourable even though O

2−

 is isoelectronic with neon. It is due to the fact that:

level 4 to level 2 : ))