How can you differentiate an element from a compound?

Asked by: Jerome de Leon

Answer

The smallest possible piece of an element is an atom. The smallest possible piece of a compound is a molecule which, in turn, is composed of any number of atoms. There are only 92 different atoms (therefore, 92 elements) that exist in nature. An unlimited number of molecules (ie. compounds) can be formed from those 92 atomic building blocks. Elements are recognized by the inability to break them down any further by chemical or physical means into simpler components. Water, for example, is a compound made up of molecules. Each of those molecules contains 2 hydrogen and 1 oxygen atom. An electric current can break down the H₂O water molecule and produced hydrogen and oxygen gas. There is no further chemical or physical way to break down hydrogen or oxygen, since they are composed of atoms. Atoms can only be broken into simpler atoms by nuclear techniques that involve splitting atomic nuclei. Hydrogen, with the simplest possible nucleus, cannot be split into any simple atoms but oxygen nuclei could be.
Answered by: Paul Walorski, B.A., Part-time Physics Instructor