Checking the count of open, closed and deleted questions of the site, I found the following stat:
What we can see, is a roughly exponential growth of the site until around middle 2015. At the time, also the count of the closed/deleted questions has shown a sharp increase, until the point that the new questions surviving the review processes are stagnating.
A healthy site has life.
New questions, new users, interesting problems, interesting review cases, and so on. And, continuous expansion.
Don't expel the new users! Teach them - and continuously motivate them to improve.
Having such a nice stat of new questions is not typical for most SE sites. The typical is a slow, linear expansion. Having an exponential increase, it is not a problem source. It is a gift.
You, avid ChemSE users, should not simply expel the "fresh meat" (both in the sense of posts and users). At least, if you are interested on a successful, living, growing site, and not in a static one, working actively to avoid its own success.
Be lenient. Invest effort to fix the fixable posts. Invest effort to "fix" the "fixable users" ;-).
The ones what you can't fix (both in the sense of posts and users), it is okay to expel (closures, downvotes), but if you avoid your growth with it, you are surely on the bad track.
It is particularly so for the first posters. They don't know too much about the site, their first experiences are crucial in their future participation. Do everything what you can, to make them feeling welcomed.