The Tonic Triad: Chord Of The First Degree

The tonic chord is our subject in today’s lesson.

We’ll be looking at the components that make it vital to the major and minor keys. Permit me to review the concept of key or tonality, to prepare you for today’s lesson.

Quick Review On The Concept Of Key or Tonality

In music, there’s a set of twelve notes (aka – “pitch sets”.) When these twelve notes are played, they tend to have a sense of neutrality until tonality is introduced or established.

The concept of tonality focuses on establishing a particular tone as the principal, and then creating a relationship between this principal tone (aka – “tonic”) and other tones.

A tonality (aka – “key”) can either be major or minor and this largely depends on some factors you can learn more about when you check out this post on two tonalities.

The tonic (which is the principal) and other tones in a given key can be seen in the scale of that given key – whether major or minor.

Scale Degree Or Technical Names

The natural major and minor scales have eight degrees respectively, and I trust that you’re familiar with the spellings of [these] scales in all twelve keys. For example, the C major scale:

…is spelled thus:

C D E F G A B C

…while the C minor scale:

…is spelled thus:

C D Eb F G Ab Bb C

However, beyond the spelling of the major scale, music scholars have technical names for every degree of the scale. These technical names reflect the relationship [in distance] between the tonic and other scale degrees in the key.

Here are the technical names of the seven degrees of the major scale…

Tonic

Supertonic

Mediant

Subdominant

Dominant

Submediant

Subtonic

Octave

In the key of C major…

C:

…is the tonic.

D:

…is the supertonic.

E:

…is the mediant.

F:

…is the subdominant.

G:

…is the dominant.

A:

…is the submediant.

B:

…is the subtonic.

C:

…is the octave.

In the key of C minor…

C:

…is the tonic.

D:

…is the supertonic.

Eb:

…is the mediant.

F:

…is the subdominant.

G:

…is the dominant.

Ab:

…is the submediant.

Bb:

…is the subtonic.

C:

…is the octave.

These technical names describe the relationship [in terms of position and function] between the components of the key and out of all these technical names, we’ll be exploring the tonic – the technical name of the first degree of the scale.

The Tonic

The tonic is the first degree of traditional scales – major or minor and is the most important tone in the key because it is the central tone (aka – “tonal center”) that every other scale tone is attracted to.

The tonic is the principal tone of the tonality. Its letter name influences everything about the tonality – name, scale tones and all worth naught.

The Influence Of Tonality In Name

The letter name of a given key is derived from the tonic of that key. The two scale excerpts below, sound alike and occupy the same finger key on the piano.

Excerpt #1:

Excerpt #2:

However, the principal tone (aka – “tonic”) of excerpt #1 is C# while that of excerpt #2 is Db. While the first excerpt is the C# major scale, the second excerpt is the Db major scale. Even though they sound alike, both scales mirror two key centers that  entirely different even though may be enharmonically related.

Suggested reading: Who Else Wants To Understand These Key Relationships.

C#:

…is the tonic of the key of C# major while Db:

…is the tonic of Db major.

So, the letter name of the first degree (aka – “tonic”) of a traditional scale determines the letter name of that key.

The Influence Of Tonality In Scale Tones and Spelling

The letter name of the tonic determines the spelling of the remaining scale tones and this has tremendous influence on the key.

If C#:

…is the tonic of a major key, the rest of the scale tones of the C# major scale:

…would be spelled thus:

D# E# F# G# A# B# C#

Conversely, if Db:

…is the tonic of a major key, the rest of the scale tones of the Db major scale:

…would be spelled thus:

Eb F Gb Ab Bb C Db

While G#:

…is the fifth degree (aka – “dominant”) of the key of C# major, Ab:

…is the dominant of the key of Db major.

While the key of C# major has a key signature of seven sharps, the key of Db major has a key signature of five flats.

Believe it or not, no two scales can share the same spelling. If the major keys of C# and Db differ in spelling, then irrespective of the relationship they have whatsoever, they are different.

Attention: Saying that there’s a difference between C# and Db may not mean so much to most people who play by the ear. This is because C# and Db practically sound the same. However, beyond playing by the ear, there are a variety of scholarly situations where both notes are treated differently and the issue of tonic and key is just one of them. If music scholars underscore this difference, then you should also take it seriously.

The Tonic Chord

A chord is a product of the harmonic relationship between notes that are related, whether they sound pleasant or not. Jermaine Griggs

The tonic chord is a chord that is founded on the first degree of the scale – the tonic. Let’s take a closer look at the tonic chords in the major and minor keys.

The Tonic Chord In The Major Key

In the key of C major:

…the tonic chord takes it root from C:

…which is the tonic, and then other chord tones are added in thirds…

C:

…and E:

…and G:

…to produce C-E-G:

…a major triad.

The tonic triad of the major key is the major triad.

The Tonic Chord In The Minor Key

Using the A minor scale:

…we can form the tonic chord of the key of A minor starting from A:

…(its tonic), then adding other chord tones in an interval of thirds…

A:

…and C:

…and E:

…to produce A-C-E:

…a minor triad.

The minor triad is the tonic chord of the minor key.

Submission: The tonic chord has the same quality with the key. The tonic chord of a major key has a major quality, while the tonic chord of the minor key has a minor quality.

The Vitality Of The Tonic Chord

The tonic chord is vital to tonality [or key environment] because it is built off a relationship between important tones of the key – the first, the third, and the fifth. Let’s examine the first, third, and fifth tones of the tonic chord.

The First

The first tone of the tonic triad [of the major or minor key] is the principal tone (aka – “tonic”) of that key. It is this first tone of the tonic chord that makes the tonic chord vital. Songs usually end with a chord progression to the tonic chord, whose root is the first tone in the key.

In addition to that, the first tone of the tonic chord influences the overall name of the key.

If the C major triad:

…is the tonic chord of a given key, then that key is the key of C major. Conversely, if the tonic chord of a given key is the C minor triad:

…then that key is the key of C minor.

The Third

The interval between the first and third tones of a scale, chord, or key, determines its overall quality.

The interval between the first and third tones of a given tonic chord has a lot to say about the key environment it belongs to (aka – “tonality“.) Given the chord below:

…as a tonic chord of a given key, the interval between its first and third tone would let you know if its a major or a minor key.

The first and third tones of the chord given above are D and F:

…an interval of a minor third.

Therefore the quality of the key where the triad given functions as the tonic triad is a minor key. Considering that the root of the given triad is D, we can say that the given triad is the tonic triad of the key of D minor.

The Fifth

The tone that has the strongest relationship with the tonic is the fifth tone (aka – ” the dominant”.) Every serious musician must have the fifth tone of the key at his or her fingertips.

Suggested reading: What States And Capitals Have To Do With Music.

Final Words

The tonic chord of any key [whether major or minor] consists of the first, third, and fifth tones of the key (aka – “stable tones“) and this makes them vital.

Due to this vitality, chord progressions return to the tonic triad because it resonates with the given key. This explains why most songs start and end with the tonic chord.

That would be all for today!

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Chuku Onyemachi

Head of Education at HearandPlay Music Group

Onyemachi "Onye" Chuku is a Nigerian musicologist, pianist, and author. Inspired by his role model (Jermaine Griggs) who has become his mentor, what he started off as teaching musicians in his Aba-Nigeria neighborhood in April 2005 eventually morphed into an international career that has helped hundreds of thousands of musicians all around the world. Onye lives in Dubai and is currently the Head of Education at HearandPlay Music Group and the music consultant of the Gospel Music Training Center, all in California, USA.

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