| A | B |
| ATOMS | SMALLEST UNIT OF MATTER WITH PROPERTIES OF SINGLE ELEMENT |
| ELEMENT | PURE SUBSTANCE OF ONE TYPE OF ATOM |
| SUBATOMIC PARTICLES | PARTICFLES THAT MAKEUP AN ATOM |
| PROTONS | POSITIVE ATOMIC PARTICLE FOUND IN THE NUCLEUS |
| NEUTRONS | NEUTRALLY CHARGED PARTICLE FOUND IN THE NUCLEUS |
| ELECTRONS | NEGATIVE ATOMIC PARTICLES FOUND SURROUNDING THE NUCLEUS |
| ATOMS | smallest constituent unit of ordinary matter that has the properties of a chemical element. |
| ELEMENT | PURE SUBSTANCE OF ONE KIND OF ATOM |
| NUCLEUS | center of an atom; made up of protons and neutrons |
| PERIODIC LAW | properties of elements tend to repeat in a regular pattern when elements are arranged in order of increasing atomic number |
| METALS | grouped on left side of periodic table; elements are shiny and conduct heat and electricity |
| NONMETALS | elements that are poor conductors of heat and electricity; grouped on the right side of periodic table |
| METALLOIDS | elements that have properties of metals and nonmetals |
| ELECTRON CLOUD | current theory or model of the atom where electrons move three dimensionally within a given area |
| ATOMIC MASS | weighted average mass of element's isotopes |
| MENDELEEV | father of periodic table: determined the relationship of elements to organize them into a table |
| MOSLEY | determined the atomic number NOT atomic weight determined order of elements in the periodic table |
| QUARK | tiny particles that make up protons & neutrons |
| FLAVORS OF QUARKS | up, down, strange, charm, bottom, and top |
| HADRONS | composite particles made of quarks |