There once was an atom of tin . . .

I've recently embarked on a very exciting collaboration with a classmate from MIT - to illustrate her chemistry poetry.  Just to get the ball rolling, I took a stab at one of my favorites. Here is a draft. The poem is about a tin atom trying to get into Club Atomic. The snooty bouncer explains that elements are admitted by the gram, and letting him in would exceed the tin allowance. Tin explains that this gives an unfair advantage to the lighter elements, such as the helium atoms filing in, and he finally convinces the bouncer that elements should be admitted by moles, or number of atoms, not by weight.