Silver becomes black as it can react with the hydrogen sulfide in the air that triggers a set of chemical reactions. This chemical reaction can also occur in case of exposure to specific chemicals as well and therefore a black layer is created. Moreover, silver oxidizes faster especially in places where there is a lot of light and humidity. Therefore, keeping silver ornaments safely can reduce the instances of such issues completely.
Even if your silver gets tarnished then you simply need to put these in a bowl of appropriate size and then cover these with white distilled vinegar. Also, add a bit of baking soda into the bowl.