The arrangement of the pitches in a piece of twelve tone music is called

Tone raw

Explanation:

A tone raw is an ordered group of twelve notes that are equally tempered pitch classes. Also, the notes doesn't repeat in the row. According to this, the answer is that The arrangement of the pitches in a piece of twelve tone music is called tone raw.

The arrangement of pitches in a piece of twelve-tone music is called a (n) A. atonality.