What is the chromatic scale composed of?

The chromatic scale is composed exclusively of semitones, which are the smallest intervals in Western music. Each note in the chromatic scale is a half step away from the next, resulting in a sequence that includes all twelve pitches available within an octave. This scale can ascend or descend, and it is often used in various musical contexts to create tension, color, and movement within a composition. Because it incorporates every pitch without skipping any, it serves as a fundamental building block for both melody and harmony.

In contrast, the other choices are based on concepts that do not align with the definition of a chromatic scale. Whole tones consist of intervals larger than semitones and would form a different scale, while notes in a single key refer to scales like the major or minor scales, which include whole and half steps in specific patterns rather than solely semitones. Lastly, fifths and octaves describe harmonic relationships rather than the linear progression of tones in a chromatic scale.