One way to name a black key is to use a sharp symbol (#)…
Sharp means the very next note up (to the right).
For example: F# is a black key, the very next note up from F…
And here are all the black keys named using sharps…
By the way, a sharp does not have to be a black key. Two white keys can also be named using a sharp. Notice that B#, the very next note up from B, is a white key and E#, the very next note up from E, is also a white key…
Putting it all together, here are all seven possible sharps…
