Checkmate for us atheists :(

[Zone]

Explain this, Christians:

If satan was an archangel who sinned and was sent to earth as punishment. Yet there is supposedly no sin in heaven.

Because people who sin in heaven are cast out of it like Satan and Adam and Eve were? Your question seems to answer itself really.

Also, why aren't there talking snakes?

Satan in disguise. In Gnosticism the snake was Jesus because they put it in reverse or something.