Here's a breakdown:
* Atoms: The basic building blocks of matter. They are the smallest unit of an element that can exist.
* Elements: Pure substances made up of only one type of atom. Examples include oxygen (O), carbon (C), and gold (Au).
* Compounds: Substances formed when two or more different elements combine chemically in a fixed ratio. This means the atoms of different elements are bound together through chemical bonds. Examples include water (H₂O), salt (NaCl), and sugar (C₁₂H₂₂O₁₁).
Key characteristics of compounds:
* New properties: Compounds have different properties than the elements they are made of. For instance, water is a liquid, while hydrogen and oxygen are both gases.
* Fixed ratio: The elements in a compound always combine in the same ratio. For example, water always has two hydrogen atoms for every one oxygen atom.
* Chemical change: The formation of a compound involves a chemical change, where new substances with new properties are formed.
Let me know if you have any other questions!
