Expanding The Chords In A Key

In my last article we looked at what basic chords are contained in a key. Now let’s expand upon these basic triads and make the chords slightly more interesting.

As we learnt, a chord is made up of every other note of the scale, so what happens if we add the next note in that sequence.

In the case of the C Major Scale our notes are:-

1^st        2^nd       3^rd        4^th        5^th        6^th        7th

C          D          E          F          G         A          B

Starting on the C note, our chord would be made up of C, E, G and B. This gives us the chord C Major 7^th. If we start on the note D, the chord consists of D, F, A, C, this is a D minor 7^th.

If we repeat this of every note we can summarise it as follows:-

Scale Degree   Starting Note   Notes in Chord            Chord Name     Chord Type

1^st                    C                     C E G B                            Cmaj7                Major 7th

2^nd                   D                     D F A C                            Dm7                  Minor 7th

3^rd                    E                      E G B D                           Em7                   Minor 7th

4^th                    F                      F A C E                           Fmaj7                 Major 7th

5^th                    G                     G B D F                          G7                      Dominant 7th

6^th                    A                     A C E G                           Am7                   Minor 7th

7^th                    B                     B D F A                           Bm7b5               m7b5

 We now have a bigger palette of chords we can use. We can mix and match, you can use majors and minors and throw in the odd extended chord here or there, you don’t have to stick to one ‘type’.

It can now get quite complicated with the terminology people use to refer to the chords. Often Roman Numerals are used. You will probably heard of a I-IV-V progression!

Roman Numeral         Chord              Chord Type      Extended Chord          Chord Spelling

I                                   C                      Major                Major 7^th                     1 3 5 7

II                                  Dm                  Minor                Minor 7^th                     1 b3 5 b7

III                                 Em                   Minor                Minor 7^th                    1 b3 5 b7

IV                                 F                      Major                Major 7^th                     1 3 5 7

V                                  G                     Major                 7^th                               1 3 5 b7

VI                                 Am                  Minor                Minor 7^th                     1 b3 5 b7

VII                                Bdim               Diminished        m7b5                          1 b3 b5 b7

In the key of C, the I-IV-V progression would be the chords C-F-G.

So now if someone says this is a VI-II-V-I progression you know what chords to play and can work them out in any key.

There are some variations in the Roman Numeral terminology when written down, for example a II chord maybe written as IIm, ii, or iim. This signifies that it is a II chord and that is minor. Although this should be known anyway, and I personally think it can overcomplicate things, but it’s all personal choice, so just be aware.