If I make an IItem interface, can items that implement that interface have custom methods/properties besides the ones declared in the interface?

I'm trying to make a simple inventory system, so I researched the topic a bit and I think I know how to start. I want to create an interface for the items, then make a list based on that interface and just select/deselect items in that list somehow, didn't quite figure that out yet. My issue is, let's say I have a Sword and an Bow, the sword could have just the basic stuff from the interface like id, name, description, damage etc but I might want the bow to explode after 3 shots or something, do I just create separate scripts for those actions or can I add them to the class that implements the interface? Thanks in advance, sorry if it doesn't really make sense, I'm learning by practice.