1. Tonic Chord (I):
- The tonic chord is built on the first scale degree (tonic).
- It serves as the home base or point of rest in a musical composition.
- It typically represents stability and resolution.
2. Supertonic Chord (II):
- The supertonic chord is built on the second scale degree.
- It creates a sense of movement and can add tension to the music.
- It often appears as a passing chord or in transitional passages.
3. Mediant Chord (III):
- The mediant chord is built on the third scale degree.
- It provides a sense of repose or stability but with a slight shift from the tonic.
- It can function as a supporting chord or as a point of departure for further harmonic movement.
4. Subdominant Chord (IV):
- The subdominant chord is built on the fourth scale degree.
- It serves as a transitional chord that leads back to the tonic chord.
- It often creates a sense of anticipation and motion towards the tonic.
5. Dominant Chord (V):
- The dominant chord is built on the fifth scale degree.
- It's the most dissonant and unstable of the principal chords.
- It creates tension and a strong pull towards the resolution on the tonic chord.
6. Submediant Chord (VI):
- The submediant chord is built on the sixth scale degree.
- It offers a temporary sense of rest or stability before moving back towards the tonic.
- It can add depth and color to the harmonic progression.
7. Leading Tone Chord (VII):
- The leading tone chord is built on the seventh scale degree.
- It's named after the seventh scale degree, which leads to the tonic.
- It creates a strong sense of resolution and is commonly used before the tonic chord.
Understanding and using these principal chords is essential for creating meaningful harmonic structures in music composition and improvisation. They provide the foundation for various chord progressions, key changes, and overall tonal coherence in a musical piece.