MUSC 101 Music Fundamentals - Spring 2012

Unit 15 - Triads and Scales

[Overview] [Syllabus]

Roman Numerals and Scale Degrees

Number the notes of the G Major scale as follows.

Using notes of the G major scale, build triads on every scale degree.

Roman Numeral Triad Names

The naming conventions for triads also apply to Roman Numerals.

Root

The Roman Numeral indicates the scale degree of the chord root; e.g.: I, ii, iii, IV V.

Quality

Upper and lower case indicate chord quality:

• Major is upper case, e.g.: I IV V
• Minor is lower case, e.g.: ii iii vi
• Diminished is lower case with an added º, e.g.: vii°
• Augmented is upper case with an added +, e.g.: III+

Inversion

The standard chord inversion symbols indicate the inversion:

• root position has no suffix
• first inversion is 6
• second inversion is 64

Diatonic Chords

A diatonic chord is a chord whose notes occur naturally in a given scale or key. For example, the d Minor chord is a diatonic chord in the key of C because its notes, D F A, occur in the C Major scale. The D Major chord, D F# A, is not a diatonic chord in the key of C because the F# does not occur in the scale of C Major. However, the D Major chord is a diatonic chord in the keys of D Major, G Major and A Major.

Major Scale Diatonic Triads

Even though this example is in C Major, the pattern of major, minor, and diminished chords is true for all major scales.

• Major chords appear on scale degrees I, IV, and V.
• Minor chords appear on scale degrees ii, iii, and vi.
• A diminished chord appears on scale degree vii.

Minor Scale Diatonic Triads

In minor keys, we'll call a chord diatonic if its notes belong to any one of the three minor scale types (natural, harmonic, or melodic) for that key.

Natural Minor

Even though this example is in C Natural Minor, the pattern of major, minor, and diminished chords is true for all natural minor scales.

• Minor chords appear on scale degrees i, iv, v
• Major chords appear on scale degrees III, VI, VII
• A diminished chord appears on scale degree ii

Harmonic Minor Scale Diatonic Triads

Even though this example is in C Harmonic Minor, the pattern of major, minor, diminished, and augmented chords is true for all harmonic minor scales.

• Minor chords appear on scale degrees i, iv
• Major chords appear on scale degrees V, VI
• Diminished chords appear on scale degrees ii, vii
• Augmented chords appear on scale degree III

Melodic Minor Scale Diatonic Triads

Even though this example is in C Melodic Minor, the pattern of major, minor, diminished, and augmented chords is true for all melodic minor scales.

• Minor chords appear on scale degrees i, ii, vi
• Major chords appear on scale degrees IV, V
• Diminished chords appear on scale degrees vi, vii
• Augmented chords appear on scale degree III

Diatonic Chord Summary

Here's a chart listing the diatonic chords in Major and the three forms of Minor. Although the keys of C Major and C minor are used in this chart, these relationships hold true for all major and minor keys. A flat "b" is used to indicate chords built on the third, sixth, and seventh notes of the minor scales when that chord root differs from the major scale. For example, the iii chord in C Major is E G B (e minor). The bIII chord in C Natural Minor is Eb G Bb (Eb Major).

Multiple Chord Names

This F Major chord occurs in several keys. It would have a different function and roman numeral name in each key.

The Three Primary Chords

The I, IV, and V are the three primary chords in major keys. The i, iv, and V are the three primary chords in minor keys. The major V chord is almost always used in minor keys. The I (i), IV (iv), and V chords account for over 90% of all chords used in most folk, pop, rock, and blues songs.

Scale Degrees and Chord Notes

Every chord consists of three notes. Here are the scale notes used for the I, IV, and V chords in a major scale and then an harmonic minor scale.

Every note of the scale can be harmonized with the I, IV, and V chords.

Major Scale

Harmonic Minor Scale

The V7 Chord

If you add a minor third on top of the V chord you get the V7 chord. The chord gets its name from the interval formed between the bottom and top notes of the chord in root position.

Chord Identification Using Roman Numerals

Naming Example

Question: Name this chord in the key of D Major.

1. Key (It's D Major - the directions said so)

2. Root (it's E)

3. Quality (It's minor)

4. Inversion (It's first inversion because the third is in the bass. The inversion suffix is 6.)

5. Roman Numeral for Chord Root (It's ii because the chord root is E, the second note in the D major scale)

6. Answer: ii6

Writing and Playing Example

Question: Write (or Play) a iiº64 chord in the key of G minor.

1. Key (It's g minor - the directions said so)

2. Scale Degree of Chord Root (The second note of the G minor scale is A.)

3. Quality (It's diminished 7 because of the º)

4. Inversion (It's a second inversion seventh chord because of the 64)

5. Answer:

[Overview] [Syllabus]

Revised by John Ellinger, Spring 2012.