In the previous module, we talked about mixtures. What about substances that are not mixtures? These are pure substances. The simplest pure substance is an element.

Elements are substances that cannot be broken down into other substances by chemical changes. That is, if you take an element, no chemical change of the substance can give you other substances that make up the element.
If we take some Hydrogen and Oxygen and let them mix, they form water. Is water an element?
  • Yes, because it is made of other elements
  • No, because it is made of other elements