13th group elements show +1 and +3 oxidation states. 14th group elements show +2 and +4 oxidation states. Incorrect order about the stability of their oxidation states is

Thallium due to inert pair effect is more stable in “+1” state;

Tl and Pb show inert pair effect. They are stable in their lower oxidation state;

Other than Tl and Pb remaining elements are stable in their group number oxidation state ;