Are we rewarded for dhikr in the mind only without uttering a single word?

Are we rewarded for dhikr in the mind of the type of saying 1000 times estagfirullah, la ilahe ilallah, Alhamdulilah, ja mukal libel kulubi thebit kalbi ala dinik in the mind only without uttering a single sound or word? In other word you say them only in the mind without moving the lips. And Does Allah accept and reward an invocation or supplication of the type: Allah please give me good understanding of quran and sunnah, Allah please give me strong iman, Allah please give me good health and solve my problems, if it is done in the mind only without moving the lips, without uttering any word or sound?