I am currently looking through a revision sheet, however it has caught me on a question 'Explain why a potassium atom can act as a reducing agent yet a potassium ion cannot'.
I have done brief searches, however none have given the answer I'm looking for. So please, why is this?
Also, if the explanation doesn't already include it; is this only the case with Potassium, and how is this to be determined? (How is it known whether it is referring to a cation or anion?)