JAMB Chemistry 2012 Paper

Concept:Zinc is not a typical transition metal, but it shares some properties with them, especially the ability to form complex ions.Explanation:Zinc has a full $\mathrm{3d^{10}}$ configuration, so it does not show variable oxidation states or form coloured ions.However, like transition metals, zinc can form complex ions such as $\left[\mathrm{Zn(NH_3)_4}\right]^{2+}$ and $\left[\mathrm{Zn(CN)_4}\right]^{2-}$.Therefore, the common characteristic is the ability to form complex ions.Answer:B. form complex ions