A chromatic scale is a scale that includes all twelve notes of an octave. Each successive note is a half-step (semitone) up or down from the previous one. On a keyboard, the chromatic scale includes all the keys (seven white and five black) that span an octave. On the guitar fretboard, the representation is even simpler: one octave is divided into 12 frets – one for each note. See also chromatic. Compare with diatonic.

 

We can think of the 12 notes of the chromatic scale as being like 12 building blocks from which different kinds of chords and scales can be built. The 12 "blocks" are:

 

R

♭2

2

♭3

3

4

♭5

5

♭6

6

♭7

7

 

where R is the root note.

 

Now we can use this block scheme to show and compare the make-up of various kinds of chords and scales.

 

Chords and scales shown using chromatic blocks
chromatic scale	R	♭2	2	♭3	3	4	♭5	5	♭6	6	♭7	7
major chord	R				3			5
minor chord	R			♭3				5
major scale	R		2		3	4		5		6		7
major pentatonic scale	R		2		3			5		6
Mixolydian mode	R		2		3	4		5		6	♭7
Indian pentatonic	R				3	4		5			♭7
harmonic minor	R		2	♭3		4		5	♭6			7
Phrygian mode	R	♭2		♭3		4		5	♭6		♭7