Dr.Trout the brilliant,but rather erratic chemist is preparing for his Amazing American Chemistry Extravaganza. He's spent so much time preparing for it,that he's forgotten to feed the lab mice.
They've started chomping through the nearest sheet of papers. That's unfortunate,as it happens to be the list of elements he must take with him.Perhaps you can help him work out which ones he needs-there are three missing.
Samples I must take