Can you down load minecraft on a chrome book because I want one and I want to play minecraft on it?

Chromebooks use Google's Chrome OS, which is essentially a web browser. These computers are not optimized for gaming. In order to play Minecraft on a Chromebook, you would have to "root" your device to access the Linux kernel (though that defeats the purpose of a Chromebook). If you would like to do this, a number of guides are available on the internet, but please be aware that this does not ensure full compatibility with Minecraft.