Tense, bluesy, and commanding. Wants to resolve to the tonic.
The G Dominant 7th chord (G7) is built on the root note G with component pitches G, B, D, F. Formula: [0 - 4 - 7 - 10 semitones]. Category: Dominant 7th (4 tones). Primary genres: Blues, Jazz, Rock and Roll, Funk.
Notes in this chord: G - B - D - F
Use as the V chord to create a strong pull back to your I chord.