piano scale
B Mixolydian
B1C♯2D♯3E4F♯5G♯6A♭7
Major with a flattened seventh: the scale that fits a dominant seventh chord without altering it.
Written out
Every accidental is written in, rather than left to a key signature, so the letters can be read one at a time.
The step pattern
BWC♯WD♯HEWF♯WG♯HAWB
What is true of it
B Mixolydian is B, C♯, D♯, E, F♯, G♯ and A, and back to B.
Its steps are W – W – H – W – W – H – W, where W is a whole step and H a half.
On the same tonic, B major differs from it by exactly one note.
Chords made only of these notes
C♯mminorC♯m7minor seventhD♯dimdiminishedD♯m7♭5half-diminished seventhEmajorEmaj7major seventhF♯mminorF♯m7minor seventh
Found by testing every chord in the catalogue against these 7 sounds, not chosen.