Which scale uses only half steps with twelve notes per octave?

• A. Chromatic Scale
• B. Whole Tone Scale
• C. Major Scale
• D. Minor Scale

Answer: (A)

This question centers on the idea of scales built purely from half steps, using all 12 notes within an octave. A half step, or semitone, is the smallest standard interval in Western tuning, moving from one pitch to the very next one. The chromatic scale does exactly that at every step, so every move is a semitone. Because you go through all the distinct pitch classes in an octave, you end up with 12 notes per octave before returning to the starting pitch.

In contrast, scales like the major and minor use a mix of whole steps and half steps and contain only seven distinct notes per octave. The whole-tone scale uses only whole steps and has six notes per octave. So the scale that uses only half steps and yields 12 notes per octave is the chromatic scale.