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What are the oxidation states of potassium in K2O, K2O2, and KO2, in that order?

1. +2, +1, and +1/2
2. +1, +1, and +1
3. +1, +4, and +2
4. +1, +2, and +4

Correct answer: +1, +1, and +1

Solution

In K2O, K has an oxidation state of +1 because oxygen is -2, leading to a total of +2 from potassium to balance it. In K2O2, each potassium still has an oxidation state of +1, as the peroxide ion (O2²-) requires two potassiums to balance the -2 charge. Similarly, in KO2, potassium remains at +1 while the superoxide ion (O2⁻) accounts for the overall charge balance.

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