In ancient times a well-known theory by the name of ‘Theory of Atomism’
was widely accepted. This theory was originally proposed by the Greeks, in
particular by a man called Democritus, who lived about 23 centuries ago.
Democritus and the people that came after him, assumed that the smallest unit
of matter was the atom. The Arabs used to believe the same. The Arabic word
dharrah most commonly meant an atom. In recent times modern science has
discovered that it is possible to split even an atom. That the atom can be split
further is a development of the 20th century. Fourteen centuries ago this
concept would have appeared unusual even to an Arab. For him the dharrah
was the limit beyond which one could not go. The following Qur’aanic verse
however, refuses to acknowledge this limit: “The Unbelievers say, ‘Never to
us will come The Hour’: say,‘Nay! But most surely, By my Lord, it will
come Upon you – by Him Who knows the unseen – From Whom is not
hidden The least little atom In the Heavens or on earth: Nor is there
anything less Than that, or greater, but Is in the Record Perspicuous.”
[Al-Qur’aan 34:3] 
This verse refers to the Omniscience of God, His knowledge of all things,
hidden or apparent. It then goes further and says that God is aware of
everything, including what is smaller or bigger than the atom. Thus the verse
clearly shows that it is possible for something smaller than the atom to exist, a
fact discovered only recently by modern science.