Why is that when a metal reacts with a non-metal, the reaction is always a redox reaction?
redox means -- oxidation and reduction at the same time. there is a new definition for oxidation and reduction. if an atom loses elctrons then it is oxidized and if an atom gains electrons it is reduced.
so, when a metal and a non metal react, there is an ionic bond formed, which means 1 loses electrons while the other gains them. so, since this reaction involves the exchange of electrons , so it is termed as a redox reaction