| A | B |
|---|
| Atom | The smallest particle into which can be divided and strill can be the same substance |
| Theory | A unifying explanation for a broad range of hypotheses and observations that have been supported by testing. |
| Electrons | The negatively charged particles found in all atoms. |
| Model | A representation of an object or system. |
| Nucleus | The tiny, extremely dense, positively charged region in the center of an atom. |
| Electron Clouds | The regions inside an atom where electrons are likely to be found. |
| Protrons | The positively charged particles of the nucleus. |
| Atomic Mass Unit | The SI unit used to express the masses of particles in atoms. |
| Neutrons | The particles of the nucleus that have no charge. |
| Atomic Number | The number of protons in the nucleus of an atom. |
| Isotopes | Atoms that have the same number of protons but have different numbers of neutrons. |
| Mass Number | The sum of the protons and neutrons in an atom. |
| Atomic Mass | The weighted average of the masses of all the naturally occuring isotopes of an element. |
