Which mode has half steps between 2-3 and 6-7 and starts on the second note of the major scale (for example, white keys from D to D)?

Which mode has half steps between 2-3 and 6-7 and starts on the second note of the major scale (for example, white keys from D to D)?

• A. Dorian mode
• B. Phrygian mode
• C. Lydian mode
• D. Locrian mode

Answer: (A)

Starting on the second degree of a major scale creates the Dorian mode. Its interval pattern is whole, half, whole, whole, whole, half, whole, so the half steps occur between the 2nd–3rd and the 6th–7th notes. If you lay out the white keys from D to D, you get D–E–F–G–A–B–C–D. The steps are D–E (whole), E–F (half), F–G (whole), G–A (whole), A–B (whole), B–C (half), C–D (whole). The two half steps align exactly with the 2nd–3rd and 6th–7th positions, identifying this as the Dorian mode. Using the white keys from D to D also shows that D is the second degree of C major, confirming the mode’s relationship to the major scale. Other modes have different placements of the half steps, so they don’t match this pattern.

Starting on the second degree of a major scale creates the Dorian mode. Its interval pattern is whole, half, whole, whole, whole, half, whole, so the half steps occur between the 2nd–3rd and the 6th–7th notes. If you lay out the white keys from D to D, you get D–E–F–G–A–B–C–D. The steps are D–E (whole), E–F (half), F–G (whole), G–A (whole), A–B (whole), B–C (half), C–D (whole). The two half steps align exactly with the 2nd–3rd and 6th–7th positions, identifying this as the Dorian mode. Using the white keys from D to D also shows that D is the second degree of C major, confirming the mode’s relationship to the major scale. Other modes have different placements of the half steps, so they don’t match this pattern.