SB 3.11.1

maitreya uvāca
caramaḥ sad-viśeṣāṇām
 aneko ’saṁyutaḥ sadā
paramāṇuḥ sa vijñeyo
 nṛṇām aikya-bhramo yataḥ
maitreyaḥ uvāca — Maitreya said; caramaḥ — ultimate; sat — effect; viśeṣāṇām — symptoms; anekaḥ — innumerable; asaṁyutaḥ — unmixed; sadā — always; parama-aṇuḥ — atoms; saḥ — that; vijñeyaḥ — should be understood; nṛṇām — of men; aikya — oneness; bhramaḥ — mistaken; yataḥ — from which.
The material manifestation’s ultimate particle, which is indivisible and not formed into a body, is called the atom. It exists always as an invisible identity, even after the dissolution of all forms. The material body is but a combination of such atoms, but it is misunderstood by the common man.

The atomic description of the Śrīmad-Bhāgavatam is almost the same as the modern science of atomism, and this is further described in the Paramāṇu-vāda of Kaṇāda. In modern science also, the atom is accepted as the ultimate indivisible particle of which the universe is composed. Śrīmad-Bhāgavatam is the full text of all descriptions of knowledge, including the theory of atomism. The atom is the minute subtle form of eternal time.