A device hitting the floor no matter what it is will cause damage to it. The question is how much. A single impact from a keyboard hitting the floor is unlikely to break it although it will cause it to be more susceptible to being noticeably damaged from another impact. Although it will likely multiple impacts for this to happen. But this is a device by device thing which depends on multiple factors including how it and where it hit the floor, what type of floor, how far did it drop, are there any material defects in the keyboard and if any where, etc.