Arrange the species O2, O2^+, O2^-, and O2^2- in order of increasing O-O bond length.

O2^2-,O2^-,O2,O2^2+

To arrange the species O2, O2^+, O2^-, and O2^2- in order of increasing O-O bond length, we need to consider the nature of the bonds and the electron configuration of each species.

1. O2: Oxygen gas (O2) consists of a stable double bond between two oxygen atoms. The bond length is determined by the strength of the bond, which depends on the number of shared electrons. In O2, both oxygen atoms share two pairs of electrons (a total of four electrons), forming a double bond. So, O2 has the shortest O-O bond length.

2. O2^+: O2^+ is an oxygen molecule that is missing one electron. Losing an electron reduces the number of shared electrons, weakening the bond. Therefore, O2^+ has a longer O-O bond length compared to O2.

3. O2^-: O2^- is an oxygen molecule that has gained one extra electron. This additional electron increases the number of shared electrons, resulting in a stronger bond. As a result, O2^- has a shorter O-O bond length compared to O2^+.

4. O2^2-: O2^2- is an oxygen molecule with two extra electrons. Just like with O2^-, the additional electrons further increase the number of shared electrons, making the bond even stronger. Therefore, O2^2- has the shortest O-O bond length among the given species.

So, arranging the species in increasing O-O bond length, we have: O2^+ < O2 < O2^- < O2^2-.