Final answer:
The correct formula for the oxide ion is O⁻², as oxide always carries a 2- charge to ensure electrical neutrality in compounds.
Therefore, the correct answer is: option A) O2-
Step-by-step explanation:
Oxide(2-) is a monoatomic oxygen. Binary compounds of oxygen containing the anion O(2-). The anion combines with metals to form alkaline oxides and non-metals to form acidic oxides.
Therefore, the correct formula for the oxide ion is O⁻². When forming compounds, the oxide ion typically carries a 2- charge.
For instance, in the formation of aluminum oxide, the formula Al₂O₃ is derived from balancing two aluminum ions with a charge of 3+ with three oxide ions, each having a 2- charge, to achieve electrical neutrality.
Similarly, in compounds like Fe₂O₃, there are two iron ions each with a 3+ charge and three oxide ions each with a 2- charge, ensuring the compound is electrically neutral.
Therefore, option A) is incorrect because oxide has a 2- charge, not a 1- charge. Options C), D), and E) are also incorrect because oxide ions do not carry a positive charge nor do they form in multiples greater than one such as O₃+.