Final answer:
The seventh note of an F-sharp dominant seventh chord is E-sharp.
Step-by-step explanation:
The seventh note of an F-sharp dominant seventh chord is the E-sharp.
A dominant seventh chord consists of four notes - the root, major third, perfect fifth, and minor seventh. In the case of an F-sharp dominant seventh chord, the notes would be F-sharp, A-sharp, C-sharp, and E-sharp. So, E-sharp is the seventh note of the F-sharp dominant seventh chord.