Redox Reactions

Redox reactions involve the transfer of one or more electrons to or from the transition metal ion.

A good example is the gradual reduction of manganate (VII) ions, MnO₄^-.

MnO₄^- > MnO₄^2- > MnO₂ > Mn²⁺

The manganese is successively reduced from oxidation state 7 to 6,4,2.

You should know the colours for all of these and the many other reduction sequences.

Sometimes it is easier to show what is being oxidised and reduced by writing half equations.

E.g Ca +Cl₂ > CaCl₂

This can be written as: Ca > Ca²⁺ + 2e^- and Cl₂ + 2^e- > 2Cl^-

Remember only one element loses or gains electrons.

The equations must balance for atoms and charge.