* Elements: The simplest pure substances, made up of only one type of atom (e.g., gold, oxygen, carbon).
* Combination: When elements combine, they form compounds. Compounds are substances made up of two or more elements chemically bonded together.
* Properties: Elements and compounds have unique properties (characteristics). For example:
* Sodium (an element) is a soft, silvery metal that reacts violently with water.
* Chlorine (an element) is a poisonous, green gas.
* Sodium Chloride (NaCl, table salt, a compound) is a white, crystalline solid that dissolves in water and tastes salty.
Key Point: The compound formed has completely different properties from the original elements. This is because the atoms of the elements are rearranged and bonded together in a new way.
