🎶 C Major and D Minor Chord Structures Explained

🧠 Starting with the Basics: The Scale

We begin with the C major scale, which consists of the following notes:

C – D – E – F – G – A – B – C

Each note is assigned a number based on its position:

• C = I (1st degree)
• D = II (2nd)
• E = III (3rd)
• F = IV (4th)
• G = V (5th)
• A = VI (6th)
• B = VII (7th)

This numbering helps us understand chord construction more easily.

🎵 Building Triads: The 1–3–5 Rule

To form a basic chord (called a triad), we use the 1st, 3rd, and 5th notes of a scale. For example:

• From C: C – E – G → This is the C major chord, often written as C, Cmaj, CM, or CΔ.
• From D: D – F – A → This is the D minor chord, written as Dm, Dmin, D–, or Db3.

Each chord has a distinct sound based on the intervals between its notes. The major chord has a brighter, more open sound, while the minor chord feels more somber or introspective.

🎼 Other Chords in the C Major Scale

Here’s how other chords are formed using the same 1–3–5 formula:

• E – G – B → E minor
• F – A – C → F major
• G – B – D → G major
• A – C – E → A minor
• B – D – F → B diminished (notated as B-b5)

📚 Summary Table of Chords in C Major

Scale Degree	Mode	Root Note	Chord Notes	Chord Name
I	Ionian	C	C – E – G	C major (CΔ)
II	Dorian	D	D – F – A	D minor (D–)
III	Phrygian	E	E – G – B	E minor (E–)
IV	Lydian	F	F – A – C	F major (FΔ)
V	Mixolydian	G	G – B – D	G major (GΔ)
VI	Aeolian	A	A – C – E	A minor (A–)
VII	Locrian	B	B – D – F	B diminished

🔍 Major vs. Minor: What’s the Difference?

To understand why D minor is minor and not major, we look at the intervals:

• D major: D – F♯ – A → The third is F♯
• D minor: D – F – A → The third is F

The difference lies in the third note. A major chord has a major third (4 semitones above the root), while a minor chord has a minor third (3 semitones above the root). So, D minor has a “flattened” third compared to D major.

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