Arrange the species O2, O2^+, O2^-, and O2^2- in order of increasing O-O bond length.
To arrange the species O2, O2^+, O2^-, and O2^2- in order of increasing O-O bond length, we need to consider the electronic configuration of each species.
O2: Oxygen molecule (neutral) has a double bond between two oxygen atoms. It has a sigma bond and a pi bond.
O2+: Oxygen cation has lost one electron compared to the neutral oxygen molecule. It has one less electron in the bonding orbitals, which leads to a weaker bond.
O2-: Oxygen anion has gained one electron compared to the neutral oxygen molecule. The extra electron participates in the bonding orbitals, resulting in a stronger bond.
O2^2-: Oxygen dianion has gained two electrons compared to the neutral oxygen molecule. The additional electrons further contribute to stronger electron-electron repulsion and shorter bond length.
So, the arrangement from increasing O-O bond length would be:
O2+ < O2 < O2^- < O2^2-