oxygen because it has only one oxidation state of -2, all the other elements in the group have multiple oxidation states.
Answer:
Kb = 7.1 x 10⁻¹³
Explanation:
Ka x Kb = Kw => Kb = 1 x 10⁻¹⁴/1.4 x 10⁻² = 7.1 x 10⁻¹³
