| A | B |
|---|
| Molecule | Two or more atoms joined together |
| Proton | Positively charged particle found in the nucleus of the atom |
| Nucleus | Center of the atom which contains the protons and neutrons |
| Atom | Smallest particle of an element |
| Electron | Particle that has a negative charge and has almost no mass |
| Neutron | Neutral particle (no charge) that are found in the nucleus of an atom |
| Atomic Mass | The number of protons plus the number of neutrons in an atom |
| Atomic Number | The number of protons and electrons in an atom |
