Copper

In our everyday world, we see and use "elements" in many ways. Advertisements talk about, "Iron is needed for your blood" or people refer to a  "Silicon Valley," but few people think of iron or silicon as elements.  Unfortunately, not all references to elements are scientifically accurate. For instance, lead in a pencil is not the element lead, but the mineral graphite which is composed of the element carbon. A five-cent nickel in American currency only has a small percentage of the metal nickel in it. The “calcium” they refer to in advertisements (needed for strong bones in milk) is not the element calcium, but a compound (mainly calcium phosphate). The calcium ion (Ca²⁺) is what is needed for the bones to incorporate into its structure.  Elemental calcium is a silver white metal and is very reactive with water.

Elements have unique physical and chemical properties.  A physical property would include characteristics like color or density, a chemical property would include reactions at the atomic level like its crystal structure or atomic structure.   An atom only has a composition made of one substance.  A single atom is unstable and usually forms a partnership or bonds with itself or other elements.  This is called a molecule, which is the stable form that allows us to observe elements in nature.   The individual boxes on the Periodic Table of the Elements, helps describe some of the physical and chemical properties of an individual element.  If you look at the Hydrogen box (Key)above,  you can find the chemical properties such as Atomic Number,  Atomic Weight (or what we will refer to as Atomic  Mass),  Crystal Structure,  and  Valence-shell configuration.   Density, Boiling Point, and Melting Point define some of its physical properties.