Nobody knows where there going to go. That's up to God.
Heaven is a free gift from God.
You can't get there by earning your way in.
You just have to figure out how to become capable of living in God's presence for eternity.
Hint: That doesn't mean that atheists who wind up there will necessarily find themselves surprised when they get there. Some of them will just react by saying "Oh, of course, now it all makes sense."