Before dealing with the topic of the Atom in Quran versus Bible versus Sciences, it is mandatory to give some statistical hints.
The total words in the Bible are 788,280 while total words in the Quran are 77,473. It follows that, the Bible is more than 10 times the Quran word-wise. In other words, the Bible has the potential of more than 10 times than the Quran to exhibit its topics.

Back to the Atom and atomic weight, they are never mentioned in the Bible and mentioned six times in the Quran.

The Atom and Atomic Weight in the Bible:

When we search the Bible; we discover that 1) No results would be found for atom, 2) No results would be found for atomic weight and
3) No results would be found for subatomic weight.
It follows that, the Bible does not mention the "Atom" or the "Atomic Weight" or the "Sub-Atomic Weight"
On the other hand, the Quran is the first written work to mention all the words: "atom", "atomic weight", and "what is less than atomic weight" in one book.

The Atom and Atomic Weight in the Quran:

The existence of particles smaller than the Atom:
In ancient times, a well-known theory named 'Theory of Atomism' was widely acknowledged. This theory was originally anticipated by Democritus, the Greek about 23 centuries ago. Democritus and the scholars who came after him, postulated that the smallest unit of matter was the atom.
The Arabs used to believe the same. The Arabic word "zarrah" most commonly meant an atom.
In recent times, modern science has discovered that it is likely to split even an atom. That the atom can be split further is a development of the 20th century. Fourteen centuries ago this notion would have appeared unusual even to both the Greeks and the Arabs. For both the Atom and "zarrah" was the limit beyond which one could not go.

Nevertheless, the Noble Quran refuses to accept this limit:

In Surah 34:3

"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 (all) is recorded in a clear and profound book".

This verse replied the Unbelievers who denied the "Hour" (the Day of Judgment in the afterlife). The verse refers to the Omniscience of Allah, His knowledge of all things, hidden or apparent. It then goes further and says that Allah 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

The subatomic weight in the Noble Quran:

In Surah 10:61
"In whatever business thou mayest be, and whatever portion thou mayest be reciting from the Qur'an,- and whatever deed ye (mankind) may be doing,- We are witnesses thereof when ye are deeply engrossed therein. Nor is hidden from thy Lord (so much as) And not the weight of an atom on the earth or in heaven the sky escapeth your Lord , nor what is less than that or greater than that , but it is recorded ( written ) in a clear profound record (Book) ".

In Surah 34:22
"Say(O Muhammad): " Call upon those whom ye assert (set up) besides Allah: they have no power - not the weight of an atom - in the heavens or on earth; no (sort of) share have they therein, nor is any of them a helper to Allah."

This is the Quranic teachings that give us a productive scientific hint about the subatomic weight, Furthermore; the Quran gives us an advice to use this scientific hint in our life. How small the atom is? If we know that every work we are doing even if it is smaller than an atom will be recorded and we will see it in the afterlife and either get rewarded or punished for it, then tell me how would be the style the mankind's life if we believe in these Quranic teachings.

If we read this verse in Surah 99:6
"On that Day will men proceed in companies sorted out, to be shown the Deeds that they had done"

This verse determines the final outcome for each of us.

In Surah 99:7
"Then shall anyone who has done an atom's weight of good, see it!"

In Surah 99:8
"And anyone who has done an atom's weight of evil, shall see it."

In conclusion, the Quran is the first book On Earth which mentions these three topics; 1) The Atom, 2) The Atomic weight and 3) The subatomic weight.
No book before the Quran mentioned these three topics together.
The thing is, Quran is not a scientific book, but it uses these three topics for the faith and religious purposes in order to emphasize three very important issues; 1) That Allah know everything's whatever it is, even if it is too smaller than the subatomic weight,
2) Our work even if it is too smaller than the subatomic weight is recorded and we will see it in the afterlife and 3)In the afterlife, the reward or punishment for our work even if it is too smaller than the subatomic weight will be the most fair.

Good rewards and the forever-paradise for the good work. "Whoever does an atom's weight of good will see it."
Bad punishments and the forever fire for the bad work.
"And whoever does an atom's weight of evil will see it."

Not only that, but Allah is the most generous; Allah will double the reward for the good deed.

In Surah 4:40
"Allah is never unjust in the weight of an atom: if there is any good (done) He doubleth it, and giveth from His own presence a great reward."

It follows that whoever does an atom's weight of good will see it and get rewarded double time for it.

Back to our main issue; one may ask this: Is the Quran quoted from the Bible? And which book precedes the sciences? The book which mentioned the atom , the atomic weight and the subatomic weight 6 times or the book which does not mention at all neither the atom or the atomic weight or the subatomic weight?