Does prayer become invalid by moving the tongue without the lips during recitation, or by the mind wandering during it? And what is the ruling on reciting the Quran while in a state of ritual impurity (janabah) before sleep?

Recitation during prayer necessitates moving the tongue and lips, except for one who is listening to his Imam, in which case it is waived for him. One whose mind wanders during prayer receives no reward for it, but is not required to repeat it. It is not permissible for a person in a state of ritual impurity (janabah) to recite the Qur'an, due to what Ahmad and the compilers of the Sunan narrated from Ali (may Allah be pleased with him) who said: "The Messenger of Allah (peace and blessings be upon him) used to teach us the Qur'an unless he was in a state of janabah." Some scholars, however, made an exception for one or two verses for seeking refuge (ta'awwudh) and the like. Accordingly, it is permissible for a person in a state of janabah to recite Ayatul Kursi and similar verses when going to sleep for protection.