Direct reaction of sodium metal with O2(g) leads to sodium peroxide, Na2O2, which contains a peroxide complex anion and is diamagnetic.
Direct reaction of potassium metal with O2(g) leads to potassium superoxide, KO2, which contains a superoxide comlex anion, and is paramagnetic.
Both complex anions contain 2 O atoms.
a. What is the charge on the peroxide ion? What is the charge on the superoxide ion? (2)
b. Use qualitative molecular orbital theory to explain why Na2O2 is diamagnetic and KO2 is paramagnetic (use the appropriate diagram from the notes. Use MO to explain the nature of the oxygen-oxygen bond in the complex anions). What is the oxygen-oxygen bond order in each case?