On oxidation, silver changes its colour to ______ and copper changes its colour to ______.

On oxidation, silver changes its colour to black and copper changes its colour to green. Silver oxidizes to form silver sulfide (Ag2S), which appears black. In moist, CO2-rich air, copper oxide further converts to green copper carbonate/hydroxide (verdigris), giving copper its characteristic green patina. Hence, on oxidation, silver turns black and copper turns green.