How is the oxidation state of a transition metal determined from the chemical formula?

Answer: The subscript of the second ion identifies the oxidation state of the transition metal

Explanation: Apex

In a chemical formula, the oxidation state of transition metals can be determined by establishing the relationships between the electrons gained and that which is lost by an atom.

We know that for compounds to be formed, atoms would either lose, gain or share electrons between one another.

The oxidation state is usually expressed using the oxidation number and it is a formal charge assigned to an atom which is present in a molecule or ion.

To ascertain the oxidation state, we have to comply with some rules:

The algebraic sum of all oxidation numbers of an atom in a neutral compound is zero. The algebraic sum of all the oxidation numbers of all atoms in an ion containing more than one kind of atom is equal to the charge on the ion.

For example, let us find the oxidation state of Cr in Cr₂O₇²⁻

This would be: 2x + 7 (-2) = - 2

x = + 6

We see that the oxidation number of Cr, a transition metal in the given ion is + 6.