This seems like a really dumb question to ask, but when I'm told that the charge on an atom (say for example, a fluorine atom) is +0.422e, does the e after the numerical value means 0.422 times the charge of an electron, 1.6 x 10-19, or is e a unit of charge? Thanks.

Hmmmm. How could it be less than the basic unit of charge e?

I am wonder in it is something like this .433e8 which is an old shorthand for .433*10^8 (coulombs).
It is not dumb, ask the teacher.
but if it is 1.6E-19, the basic unit of charge, it would be a miracle to have .422 of that to have, one could get a Nobel prize for it.