In some of the reactions thallium resembles aluminium, whereas in others it resembles with group I metals. Support this statement by giving some evidences.

Thallium belongs to group 13 of the periodic table. The most common oxidation state for this group is + 3. However, heavier members of this group also display the + 1 oxidation state. This happens because of the inert pair effect. Aluminum displays the + 3 oxidation state and alkali metals display the + 1 oxidation state. Thallium displays both the oxidation states. Therefore, it resembles both aluminum and alkali metals. Thallium, like aluminum, forms compounds such as TlCl₃ and Tl₂O₃. It resembles alkali metals in compounds Tl₂O and TlCl.