Question

boron forms no compounds in unipositive state but thallium in unipositive state is quite stable.Explain

Answer 1

because elements like B C N O are only stable in their highest oxidation state

Answer 2

Answer: This happens due to inert pair effect.

Explanation:

Boron and thallium are the elements which belong to the same group that is Group 13. The common oxidation state for this group is +3.

Inert pair effect is the tendency of the two paired up electrons that are present in the outermost s-orbital to remain unshared while bonding.

Boron belongs to the period 2 and Thallium belongs to Period 6. The inert pair is more prominent in while going down in the group as as the period increases, therefore thallium has more inert pair effect than boron. So, the two s-electrons in thallium remain unbonded and the oxidation state of +1 also appears.

Hence, in thallium, uni-positive state is stable than the same state in boron.