An atom is the smallest "piece" of an element that still has the properties of that element. For example, an atom of gold is the smallest piece of gold that still acts like gold ? ... When many atoms come together, atoms tend to form molecules. A molecule is a combination of two or more atoms bonded together. For example, a molecule of water (designated by the symbol H 2 O) consists of two hydrogen atoms and an oxygen atom which are in a "relationship" ? ...