Q.

Consider the following elements In, Tl, Al, Pb, Sn and Ge.

The most stable oxidation states of elements with highest and lowest first ionisation enthalpies, respectively, are           [2025]

1 +2 and +3  
2 +4 and +3  
3 +4 and +1  
4 +1 and +4  

Ans.

(2)