Unit 21 · Intermediate

Diatonic Harmony in Major Keys

Understand why common progressions work.

Lesson
Hear and build function inside a major key
Estimated time
145 minutes
Status
Previewing
Preview available

Complete the required prior unit before this unit can be marked complete. You may still read and try every activity.

What you will learn

Harmonize a major scale as seven triads, connect inversions in several keys, classify tonic, predominant, and dominant function, distinguish four cadence types, and write four purpose-built progressions.

Why this matters: Diatonic harmony explains why chords create stability, departure, preparation, tension, and return. Function turns a memorized chord list into choices that can be heard, transposed, and revised.

Before you begin

Major-scale construction · Triad qualities and inversions · Roman numerals · Voice leading · Lead-sheet transposition

Scale degree and chord quality create function

Stacking alternating scale tones above each major-scale degree yields I, ii, iii, IV, V, vi, and vii diminished. In C: C, Dm, Em, F, G, Am, B diminished.

Tonic-family chords I, iii, and vi can provide relative stability; predominant ii and IV move away and prepare; dominant V and vii diminished contain directed tension. Context can change emphasis, so listen to the motion instead of trusting the label alone.

Progression · Key C · 4/4

Harmonize every degree in C major

Degree 1CI · 1
Degree 2Dmii · 2m
Degree 3Emiii · 3m
Degree 4FIV · 4
Degree 5GV · 5
Degree 6Amvi · 6m
Degree 7Bdimvii° · 7dim

Sing C-D-E-F-G-A-B roots before playing. Build each triad from scale-only thirds, then connect the nearest inversion instead of jumping to seven unrelated grips.

Progression · Key C · 4/4

Four cadences answer different formal questions

AuthenticG-CV-I · 5-1
PlagalF-CIV-I · 4-1
DeceptiveG-AmV-vi · 5-6m
HalfDm-Gii-V · 2m-5

Authentic and plagal cadences arrive on tonic through different preparation. Deceptive motion redirects dominant tension to vi. A half cadence stops on V and therefore sounds open.

Lead sheet · Key C · 4/4 · 72 BPM

Four Gates: Trace function before chord names

Capo: None

Statement × 2

Ctonic; settleAmtonic familyDmpredominantGhalf cadence

Answer × 2

FpredominantGdominantEmtonic substituteAmdeceptive color

Close × 1

DmprepareGtensionCauthentic arrival

Hear each section as a functional route. Revoice with compact triads, sing bass movement, then transpose the function plan to G or D.

1 · Model

Observe: major-key harmony and cadences

Observe stage for major-key harmony and cadences, with actions and success criteria stated in text.

  1. Sing the seven roots before hearing harmonized triads.
  2. Observe how quality follows scale-only thirds.
  3. Compare authentic, plagal, deceptive, and half-cadence endings.

Help you can use: Complete written model · Visible success criteria

  • Chord roots and qualities belong to the key.
  • Functional labels are supported by heard motion.
  • Cadence types and transpositions preserve their relationships.
2 · Guided attempt

Try with prompts: major-key harmony and cadences

Try with prompts stage for major-key harmony and cadences, with actions and success criteria stated in text.

  1. Build C-major triads one degree at a time.
  2. Sort them into tonic, predominant, and dominant families.
  3. Write one four-chord route from tonic through predominant and dominant.

Help you can use: Numbered steps · One-variable diagnosis

  • Chord roots and qualities belong to the key.
  • Functional labels are supported by heard motion.
  • Cadence types and transpositions preserve their relationships.
3 · Fade support

Use fewer prompts: major-key harmony and cadences

Use fewer prompts stage for major-key harmony and cadences, with actions and success criteria stated in text.

  1. Use Roman numerals without chord-name prompts.
  2. Transpose two functions to G major.
  3. Identify cadence type from its final motion before checking.

Help you can use: Check the model only after an attempt

  • Chord roots and qualities belong to the key.
  • Functional labels are supported by heard motion.
  • Cadence types and transpositions preserve their relationships.
4 · Independent attempt

Perform independently: major-key harmony and cadences

Perform independently stage for major-key harmony and cadences, with actions and success criteria stated in text.

  1. Harmonize a prompted major scale and explain each quality.
  2. Perform four progressions with distinct structural purposes.
  3. Analyze and transpose an unfamiliar diatonic progression.

Help: Complete without prompts or a model.

  • Chord roots and qualities belong to the key.
  • Functional labels are supported by heard motion.
  • Cadence types and transpositions preserve their relationships.

Reflect

Explain what the progression is doing

Write one progression for stability, one for departure, one for unresolved tension, and one for surprise. Label Roman numerals, function families, cadence, and the bass motion you hear.

Guided practice

Build the skill in manageable steps

Exercise 1

Sing, stack, verify

Derive diatonic triads before checking a chart.

  1. Write or speak the major scale.
  2. Sing each root in order.
  3. Stack scale degrees 1-3-5 above each root.
  4. Name quality and verify on guitar.
Success sounds or feels like
  • Seven roots remain in key.
  • Quality pattern is major-minor-minor-major-major-minor-diminished.
  • Inversions connect with small motion.
Make it smaller when
  • Harmonize degrees I, IV, and V.
Increase difficulty when
  • Use a key with two or more accidentals.
Exercise 2

Same phrase, four endings

Hear cadence as formal behavior.

  1. Keep the first two measures unchanged.
  2. End once with V-I, IV-I, V-vi, and ii-V.
  3. Name arrival, redirection, or openness.
  4. Choose which ending fits four different section purposes.
Success sounds or feels like
  • Every ending is performed in time.
  • Cadence names match final motion.
  • The chosen formal effect is described audibly.
Make it smaller when
  • Compare authentic and half cadences only.
Increase difficulty when
  • Transpose all endings before replaying.

Common mistakes

Match the problem to a better next try

All seven scale roots receive major chords.

Likely cause: Root membership is being confused with chord construction.

Try: Stack only notes from the key and measure each third.

Roman numerals are correct but no tension or arrival can be heard.

Likely cause: Symbols were added without singing roots or comparing endings.

Try: Sing bass motion and play only the final two chords of each cadence.

The harmonized scale is interrupted by large grip changes.

Likely cause: Root-position shapes were chosen for every degree.

Try: Use inversions that keep common tones and move each voice minimally.

Knowledge check

Explain the practice decision

1. What is the diatonic triad-quality pattern in major?
2. Which pair most often serves predominant function in a major key?
3. Which motion defines a basic deceptive cadence?

Check your work

Hear and build function inside a major key assessment

Complete every required criterion and record the requested reflection or value.

You check off guitar-playing tasks yourself. FretGarden only grades tasks where you tap, click, or choose an answer on screen.

Review plan

Return before the idea fades

Now

Sing roots and state the major-key quality pattern.

Next session

Harmonize a new major key and perform four cadences.

One week

Analyze function and cadence in an unfamiliar progression.

Long term

Use function to transpose, revise, and explain songwriting choices.

Optional extension: Keep one soprano note constant while reharmonizing it with three diatonic function families.