- Everything is made from atoms, including you.
- Atoms are tiny particles that are far too small to see, even with a microscope.
- We often draw atoms as circles, to make drawing diagrams simpler.
- There are over a hundred different elements.
- The atoms in a particular element are the same as each other, and they are different from the atoms of all other elements. For example, lead and gold are elements. A piece of pure gold contains only gold atoms. A piece of pure lead contains only lead atoms.
- The atoms of some elements do not join together, but instead they stay as separate atoms.
- The atoms of other elements, such as hydrogen and oxygen, join together to make molecules.
- A compound is a substance that contains atoms of two or more different elements, and these atoms are chemically joined together.
- There are very many…