Matter is anything that has mass and takes up space. All matter is made up of atoms.

Everything is a galaxy is matter.

An atom is the smallest unit of a chemical element. If an atom is broken up smaller, it is no longer an element.

A ladybug is small—though nowhere near as small as an atom.

Each element is made up of one type of atom. There are 120 chemical elements in total.

Rocks are made of different elements.

When two or more atoms are joined together, this creates a molecule. A molecule can be made of different atoms, or the same.

Molecules are too small to see with the naked eye; you have to use a microscope.

A compound is formed when two or more DIFFERENT atoms are joined together. All compounds are also molecules, though not all molecules are compounds.

All of those leaves are different, like the elements in a compound.

The Periodic Table of Elements

The subscript is the small number on the right side of the element. This shows how many of that element is being used.