Improvisation on dominant chords is maybe the first to be learn by improvising musicians. Dominant chords are frequently embellished by all kinds of extensions so any musician must be familiar to the modes he/she would play on them.
• The blues scale may be played on chords that include the 9th and the 11th and on the 7#9 chord.
• The most popular mode on 7,9,(11, 13) is the mixolydian mode . For instance, on a C9 chord you may play C mixolydian (the 5th mode of the F major scale).