MCQ
Thalium shows different oxidation states because
- AIt is a transition element
- ✓Of inert pair effect
- COf its amphoteric character
- DOf its higher reactivity
Electronic configuration of Thallium is $[ Xe ] \,4 f ^{14} \,5 d ^{10}\, 6 s ^2 \,6 p ^1$.
$d$ and $f$ electrons of inner shells provide poor shielding, thus the attraction of the nucleus on the $s$ electrons of the outermost shell increases. This is called the inert pair effect.
Whereas, $s$ electrons provide strong shielding to $p$ electrons, thus making it easy for the $p$ electrons to be released.
Thus, although Thallium shows $+3$ and $+1$ oxidation states, $+1$ is more common.
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|
LIST $I$ (Compound / Species) |
LIST $II$ (Shape / Geometry) |
| $A$ $\mathrm{SF}_4$ | $I$ Tetrahedral |
| $B$ $\mathrm{BrF}_3$ | $II$ Pyramidal |
| $C$ $\mathrm{BrO}_3^{-}$ | $III$ See saw |
| $D$ $\mathrm{NH}_4^{+}$ | $IV$ Bent $T$-shape |
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