The sum of oxidation state of the metals in Fe ( CO ) _ 5 , VO ^ 2...

In the complex $Fe ( CO{)}_{5}$, take the oxidation number of $Fe$ be $x$ . Carbonyl is a neutral ligand which doesn't have any charge. So the oxidation number of $Fe$ would be

$x - 0 \times 5 = 0 = 0$

Hence, the oxidation number of iron in this complex is$0$.

let oxidation state of vanadium in ${VO}^{2 +} = x$.

so, $x + ( - 2 ) = + 2 ⇒ x = + 2 + 2 = + 4$

Tungsten trioxide consists of one tungsten atom and three oxygen atoms. Tungsten is a $d -$block metal from group $6$and has an oxidation state $+ 6$in the compound.

Then, Sum of oxidation state of metals in the given compounds $= 10$