General Electronic Configuration & Oxidation S- Group 13tates

General Configuration: $$ns^2 np^1$$

Oxidation States Order:

$$\text{Stability of } +3 \text{ State: } \text{B} > \text{Al} > \text{Ga} > \text{In} > \text{Tl}$$

$$\text{Stability of } +1 \text{ State: } \text{Tl} > \text{In} > \text{Ga} > \text{Al} > \text{B}$$

Concept: Group 13 elements exhibit +3 and +1 oxidation states. The stability of the +1 state increases down the group while $$+3$$ stability decreases due to the Inert Pair Effect (reluctance of $$ns^2$$ electrons to participate in bonding due to poor shielding by inner d and f electrons).