[jprete]

But atoms literally get heavier as you go down the table. If the actual elements were ordered in complexity of compounds, hydrogen would be at the bottom of the table, and periodic table posters would have to come with a special “carbon” sticker to attach to the floor.

[gcanyon]

Yes, I'm agreeing that mass (or more accurately, proton count) makes sense for the elements. I'm saying it doesn't make sense for tools.