# Diatonic triads

*Module 8 · Lesson 1: Harmony in a key · BazzLow*

> Build the seven triads of a major key and know their qualities.

Before this lesson: [7.3 Diminished and augmented triads](https://bazzlow.com/en/triads-and-arpeggios/diminished-and-augmented-triads/) · [5.4 Keys and key signatures](https://bazzlow.com/en/major-scale-and-keys/keys-and-key-signatures/)

You know the scale of a key. Now we build the chords of that key, one on every note of the scale.

## Seven chords from seven notes

**Diatonic** means “using only the notes of the key”. Build a triad on each degree of the major scale by stacking 3rds with scale notes only, and you get the **seven diatonic triads**, the **diatonic chords** of the key. In C major:

*The diatonic triads of C major.*

| Degree | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Chord | C | Dm | Em | F | G | Am | B° |
| Quality | major | minor | minor | major | major | minor | diminished |

The pattern **major – minor – minor – major – major – minor – diminished** is the **same in every major key**. In G major the chords are G, Am, Bm, C, D, Em, F♯°.

*The diatonic triads of the 12 major keys.*

| Key | I | ii | iii | IV | V | vi | vii° |
| --- | --- | --- | --- | --- | --- | --- | --- |
| C | C | Dm | Em | F | G | Am | B° |
| D♭ | D♭ | E♭m | Fm | G♭ | A♭ | B♭m | C° |
| D | D | Em | F♯m | G | A | Bm | C♯° |
| E♭ | E♭ | Fm | Gm | A♭ | B♭ | Cm | D° |
| E | E | F♯m | G♯m | A | B | C♯m | D♯° |
| F | F | Gm | Am | B♭ | C | Dm | E° |
| F♯ | F♯ | G♯m | A♯m | B | C♯ | D♯m | E♯° |
| G | G | Am | Bm | C | D | Em | F♯° |
| A♭ | A♭ | B♭m | Cm | D♭ | E♭ | Fm | G° |
| A | A | Bm | C♯m | D | E | F♯m | G♯° |
| B♭ | B♭ | Cm | Dm | E♭ | F | Gm | A° |
| B | B | C♯m | D♯m | E | F♯ | G♯m | A♯° |

## The chord family

Most songs in a major key use mainly these chords, the **chord family** of the key, and most of all the three major ones (degrees 1, 4 and 5) and the three minor ones (2, 3 and 6).

Every scale note belongs to **three diatonic chords**: once as a root, once as a 3rd and once as a 5th. In C major, the note C is in C, F and Am. This is how chords are chosen under a melody (lesson 9.6).

The Key Chords tool shows the chords of every major key, with bass boxes.

## Try it

In C major, play the root, 3rd and 5th of each diatonic chord in order, from C to B°, saying its name and quality.

## New terms

- diatonic
- diatonic chord
- chord family

Page: https://bazzlow.com/en/harmony-in-a-key/diatonic-triads/