C7
The dominant seventh adds a flat seventh to a major chord. That tension wants to resolve, which is why it leads back to the home chord in so many songs, and why the blues is built almost entirely from 7th chords.
Root
Type
E
C
A#
E
C
Shape
The dominant seventh adds a flat seventh to a major chord. That tension wants to resolve, which is why it leads back to the home chord in so many songs, and why the blues is built almost entirely from 7th chords.