F# is a sharp key. A key is either sharp, natural, or flat. Never all three or two. Only one.
There are no flats in D major, but there are 2 sharps. C sharp and F sharp.
There are no flats in Em, just an F sharp!
C major: no sharps, no flats F major: no sharps, B flat Bb (B flat) major: no sharps, B and E flat Eb major: no sharps; B, E, and A flat Ab major: no sharps; B, E, A, and D flat Db major: no sharps; B, E, A, D, and G flat Gb major/F# (F sharp) major: no sharps; B, E, A, D, G, and C flat / F, C, G, D, A, and E sharp; no flats B major: F, C, G, D, and A sharp; no flats E major: F, C, G, and D sharp; no flats A major: F, C, and G sharp; no flats D major: F and C sharp, no flats G major: F sharp, no flats
F sharp C sharp G sharp D sharp
A chromatic scale will, by definition, have sharps and/or flats.
E minor contains an F-sharp and no flats. E F# G A B C D E
D major contains an F-sharp and C-sharp.
There are no flats in b-minor. B major has two flats, both B-flat and A-flat, but b-flat minor is the relative minor of D-major, which has a sharp key signature. The sharps in b-minor are F-sharp and C-sharp.
E minor contains one sharp: F.
Just one, and that would be F sharp.
an f minor scale written with sharps instead of flats, that uses e sharp as the tonic.
There are different rules. For major keys, the rule is this (by the way, # means sharp): C major scale- 0 sharps or flats G major scale- 1 sharp - F sharp D major scale- 2 sharps - F and C sharp A major scale- 3 sharps - F, C, G sharp E major scale- 4 sharps - F, C, G, D sharp B major scale- 5 sharps - F, C, G, D, A sharp F# major scale- 6 sharps - F, C, G, D, A, E sharp C# major scale - 7 sharps - F, C, G, D, A, E, B sharp. For major keys with flats: F major scale - 1 flat - B flat B flat major scale - 2 flats - B, E flat E flat major scale - 3 flats - B, E, A flat A flat major scale - 4 flats - B, E, A, D flat D flat major scale - 5 flats - B, E, A, D, G flat G flat major scale - 6 flats - B, E, A, D, G, C flat C flat major scale - 7 flats - B, E, A, D, G, C, F flat So as you might have noticed, in increasing order of sharps it is: F, C, G, D, A, E, B. And the increasing order of flats is B, E, A, D, G, C, F. If you notice the order of sharps is the opposite of the order of flats.