Compare the chemical stability of the highest oxidation states between the elements of the series an — d and f Block Elements Chemistry Question
Question
Compare the chemical stability of the highest oxidation states between the elements of the $3d$ series and those of the $4d/5d$ series. Which of the following statements is strictly correct regarding this periodic trend?
💡 Solution & Explanation
Unlike the $p$ -block where lower oxidation states become more stable down a group (inert pair effect), in the $d$ -block, the higher oxidation states become significantly more stable down a group. For example, $Mo(VI)$ and $W(VI)$ (Group 6, $4d$ and $5d$) form highly stable oxyanions ($MoO_4^{2-}$, $WO_4^{2-}$), whereas $Cr(VI)$ ($3d$) is a remarkably strong oxidising agent, readily reducing to $Cr^{3+}$.