| A | B |
|---|
| Atom | The smallest particle that can exist alone or in combinations. |
| Atomic Mass | The mass of an atom expressed in atomic mass units. |
| Atomic Mass Unit | Is 1/12 the mass of a C-12 atom as 1u |
| Atomic Number | The number of protons that an element has in the nucleus. |
| Atomic Structure | The general structure of particles within an atom. |
| Average Atomic Mass | The weighted average of atomic masses and their naturally occurring isotopes. |
| Avogadro’s Number | The number of particles in exactly one mole of pure substance. |
| Electrons | Negatively charged particles with no mass units. |
| Isotopes | Atoms of the same elements with different mass numbers. |
| Law of Multiple Proportions | Different compounds are composed of the same two elements; their masses can be combined and expressed as ratios of small whole numbers. |
| Mass Number | The total number of protons and neutrons in the nucleus. |
| Molar Mass | The mass in grams of one mole of pure substance. |
| Mole | The same number of particles as is the amount of a substance that contains the same number of particles as the number of atoms in exactly 12g of carbon 12. |
| Neutron | Neutral particle with one mass unit found in the nucleus. |
| Nuclear Forces | The forces inside of a nucleus that hold protons and neutrons together. |
| Nucleus | Dense, positively charged center of the atom containing protons and neutrons. |
| Nuclide | General term for the isotope of an element. |
| Protons | Positive particle with one mass unit found in the nucleus. |
