Question

Maximum oxidation state is shown by:

• A. $Os$
• B. $Mn$
• C. $Cr$
• D. $Co$

Answer 1

The correct option is A $Os$

The electronic configuration of osmium is $\left[Xe\right]4f^{14}5d^{6}6s^2$. Osmium shows maximum oxidation state. It is +8.
$Mn,Cr$ and $Co$ show +7, +6 and +4 oxidation states.