Final answer:
The seventh note of an F dominant seventh chord is E-flat.
Step-by-step explanation:
The note that is the seventh of an F dominant seventh chord is E-flat. A dominant seventh chord consists of a major triad plus a minor seventh above the root. For an F major triad, the notes are F (root), A (major third), and C (perfect fifth). To make it a dominant seventh chord, you add a minor seventh above the root, which, in this case, is E-flat. Therefore, the four notes of an F dominant seventh chord are F, A, C, and E-flat.