F# G# A# B C# D# E# F#
Yes, that's an E# in there.
A, B, C sharp, D, E, F sharp, G sharp, A
The D Major scale has two sharps, F and C. The notes in this scale are D, E F sharp, G, A, B, C sharp, D.
That would be either A major or F# minor.
E F sharp G sharp A B C sharp D sharp E
Eight: a b c-sharp d e f-sharp g-sharp a
C-sharp major is C# D# E# F# G# A# B# C#.
C#, d#, e#(f), f#, g#, a#, b#(c), c#
The mediant of any major scale is the note that is a third above the tonic (root) of the scale. In the key of F sharp major, the tonic is F sharp, so the mediant would be A sharp.
No scale has an F♯ and a D♯ alone, however the keys of E, B, F♯, C♯ major and likewise their relative minors have both the notes F♯ and D♯ as degrees in their scale.
G major, D major, E major, B major, F sharp major, F sharp minor, A sharp major, etc.
F sharp major has 6 sharps/G flat major has 6 flats. These two scales will sound totally identical when played on any instrument, the notes to this scale are: F♯/G♭, G♯/A♭, A♯/B♭, B/C♭, C♯/D♭, D♯/E♭, E♯/ F, F♯/G♭. Notes before the / are F♯ major notes and notes after the / are G♭ major notes.
A♭ major scale has the following notes (in ascending order): A♭ - B♭ - C - D♭ - E♭ - F - G - A♭