Is playing the Qur’an in the schoolyard while students are preoccupied with talking and not listening to it considered a sin, or is there no harm in it?

There is no harm in playing the Holy Quran in the schoolyard or elsewhere, as long as it is not done in a disrespectful manner. Listening to the Holy Quran outside of prayer is recommended, not obligatory. Whoever listens and pays attention to the Quran will be rewarded, and whoever does not pay attention to it commits no sin.