Some argue that the whole of the written Torah was given at Sinai. Others, that the whole written Torah was given along with the entire Oral Torah.
Others argue that only the Ten Commandments were given. And indeed, an early Hasidic master, Rabbi Mendel of Rymanov, argues that the revelation at Sinai consisted of only the first letter of the first word of the Ten Commandments: the aleph (the first letter of the Hebrew alphabet) of the word anochi, “I am.” Interestingly, an aleph, by itself, is silent. Gershom Scholem, a leading scholar of Jewish mysticism, comments, “with his daring statement that the actual revelation to Israel consisted only of the aleph, Rabbi Mendel transformed the revelation on Mount Sinai into a mystical revelation, pregnant with infinite meaning, but without specific meaning.”