| A | B |
|---|
| Element | A substance that can't be broken down into simpler chemical substances. |
| Atom | Smallest particle of an element that has the characteristics of that element. |
| Nucleus | The center of the atom. |
| Isotopes | Atoms of the same element that have different numbers of neutrons. |
| Compound | A substance that is composed of atoms of two or more different elements that are chemically combined. |
| Covalent bond | When two atoms share electrons, such |
| Molecule | A group of atoms held toget |
| Ion | A charged particle |
