Broken chords

We have already learned that intervals can appear as harmonic or melodic intervals i.e. as two simultaneous or two successive notes. The case is similar for the chords. 

A block chord is a chord in which all notes sound simultaneously.

A broken chord is a chord in which all notes appear in succession.

An arpeggio is a common type of broken chord in which the notes of a chord are played rapidly, one after the other, from the bottom of the chord to the top. In a score, it is marked with a wavy vertical line in front of a chord. The next passage from Chopin’s Nocturne in C minor is a good example of arpeggiated chords. Here, we have very wide chords. In fact, they are so wide that its notes cannot be played simultaneously by any hand. However, they can be played as an arpeggio together with the sustain pedal (which sustains the duration of the played tones even when the piano keys are depressed), which creates an effect similar to playing them simultaneously.    

Figure: Arpeggiated chords in Chopin's Nocturne in C minor

An Alberti bass is a common type of the broken chord which is used as an accompaniment for the melody. It plays the notes of a chord in a characteristic sequence. It occurs quite common, for instance, in the left hand of Mozart’s piano compositions. The next figure shows eight examples of the Alberti bass in the left hand, at the beginning of Mozart’s Piano sonata in C major K. 545.

Figure: An Alberti bass in the left hand at the beginning of Mozart’s Piano sonata in C major K.545