| A | B |
|---|
| Representative Elements | s and p block elements (groups 1,2, 13-18) |
| Transition metals | d block elements (groups 2-12) |
| Valence Electrons | electrons in the outermost energy level, electrons lost or gained, (s and p block elements) |
| anions | gain electrons, negatively charged ion |
| cation | lose electrons, positiviely charged ion |
| group | (family) vertical column on the periodic table, elements with similar properties |
| periodic law | the periodic table is grouped by increasing atomic number and chemical/physical properties |
| group numbers | tells the number of valence electrons |
| period numtbers | tells the energy levels |
| metals | located left of the zigzag |
| nonmetals | located right of the zigzag line |
| Meendeleev | arranged the periodic table by atomic mass |
| Mosely | arranged the periodic table by atomic number |
| Mosely and Meendeleev | organized the elements into groups based on similar properties |
