system
Given the following post, respond as if you're commenting on Reddit:
human
Is there a limit to how many atoms there can be in a molecule?
gpt
Depending on your definition of molecule, it's pretty clear there's no limit in a practical sense. Crystals are essentially giant molecules, if by that we mean continuous blocks of atoms connected by sharing electrons. (Blocks of metal could also count.)

There's no fundamental difference between that and what we typically think of as a molecule, but the term molecule is pragmatically reserved for items that aren't arbitrary in size. (Although we do talk about DNA molecules, which can be sized arbitrarily.)