Metal Compounds and Mixtures

Rust

Tarnished Silverware

What happens of iron rust or when silver and copper form a blackish tarnish?  In these cases, the atoms of a metal have combined with atoms of a nonmetal.  This process is called corrosion.  Corrosion is the gradual "eating away" of a metal because it reacts chemically to form a compound that weakens it.


The most reactive metals are the quickest to corrode.  Sodium metal must be stored under oil to keep the sodium metal from reacting with oxygen within seconds.  

Most of the time, metals aren't used as their elemental form.  While still, melted, other metals and nonmetals are added to form an alloy, which is the mixture of two or more metals and nonmetals.  For example, gold is too soft  to make durable jewelry.  When mixing gold with copper, silver, nickel, or palladium, the gold gets harder.

Fun Facts:

• Pure copper is only used for wires to conduct electricity.



Copper Wire

• The use of bronze helped civilizations grow in size and power, and this time in history is called the Bronze Age.