The very short answer is “Yes”…however, I would want to add several guiding principles. Here are a few that come to mind:
Remember: Young children are like sponges, taking in information. They do not have the same emotional connotations that we associate with hell and judgment. However, they do experience punishment and pain in their lives. Mommy and Daddy make rules and give commands. They set parameters for acceptable behavior and implement certain consequences for wrong behavior.
I think the bigger issue in the preschool years is this: We should be striving to lay a solid foundation for the truth about hell. How can we do this?
Now apply this to the fall: God created Adam and Eve and made a beautiful garden for them to live in. God is good and loving and gave them all sorts of wonderful foods to enjoy—lots and lots and lots of delicious food! But God said there was one and only one tree that they couldn’t eat the fruit from. God knows best. He gave them that command for their own good so that they would be happy. They should obey God. But do you know what Adam and Eve did?...
Children can easily relate to being helpless in various situations and needing to rely on someone else. We can use this to help them understand their need to depend completely on Jesus to fix their biggest problem. Therefore, while we need to be intentional in communicating the truth about hell to them in the most serious terms, we must always earnestly and gladly point to the incredible free and priceless gift held out to them—Jesus the Savior!
You also might be interested in this short video, in which John Piper answers the question: Should first graders be taught about the wrath of God?