Radio wave is an electromagnetic wave ; what is an electromagnetic wave?? An electromagnetic wave are waves that does not require material medium for their propagation... So radio wave can move through a vacuum because it's an electromagnetic radiation...
Sound wave is a mechanical wave ; what is a mechanical wave?? Waves that require material medium for their propagation.. Other examples include :water wave,
Light wave is also an electromagnetic wave(radiation) it does not require a material medium for its propagation it defines every other electromagnetic wave other example including... ; gamma ray, X-ray, ultraviolet ray, visible light, infrared Ray, radio wave(which I discussed first)
Sound wave can not move through a vacuum because it requires a material medium.. You can talk to someone and the person hears you because the air particles serves as the material medium....
