| Protons | | After Democritus's time, experiments where primarily carried out by. |
| AlkaliMetals | | Each element is composed of this particle. |
| Tellurium | | Latin name for Cu. |
| NobleGases | | Discovered a useful way to organize elements. |
| Non-metals | | Te |
| Electron | | Positively charged particles. |
| Metals | | The first chemists lived in this time. |
| Uranium | | 6 2 ion charge. |
| Thomson | | Diagonal row between metals and non-metals. |
| Neutrons | | Shiny, malleable, and ductile. |
| Halogens | | Most stable elements. |
| Alchemists | | Dull and brittle. |
| Lavoisier | | Elements are listed in order of this. |
| Cuprum | | His was the "rasin bun model". |
| Period | | Numbered 1 to 7 on the Periodic Table. |
| Uub | | Core of the atom. |
| AtomicMass | | Most reactive metals. |
| Nucleus | | First discovered subatomic particle. |
| Mendeleev | | U |
| Atom | | Each vertical column on the Periodic Table. |
| Family | | A 1770s French scientist |
| Tungsten | | Neutral particles. |
| Metalloids | | 165 neutrons |
| MassNumber | | Group 17 |
| StoneAge | | The sum of the number of protons and neutrons in an atom. |
