| A | B |
|---|
| traid | a group of three elements with similar properties |
| law of octaves | the same properties appear every eighth element when the elements are listed in order of their atomic masses |
| periodic law | the properties of the elements that are a periodic function of their atomic masses |
| periodic table | a pictorial arrangement of the elements based upon their atomic numbers and electron configurations |
| transition element | an element whose highest energy electron is in a d sublevel |
| lanthanoid series | fourteen elements beginning with lanthanum in which the arrow diagram predicts the highest energy electrons to be in the 4f sublevel |
| actinoid series | fourteen elements beginning with actinium in which the arrow diagram predicts the highest energy electrons to be in the 5f sublevel |
| period | a horizontal row of the periodic table |
| group | the elements of a vertical column in the periodic table |
| octet rule | the tendency of atoms to gain or lose electrons so that they acquire eight electrons in their outer level |
| family | the elements composing a vertical column in the periodic table |
| metal | an elemnet that tends to lose electrons in chemical reactions |
| nonmetal | an element that tends to gain electrons in chemical reactions |
| metalloid | an element that has characteristics of a metal and a nonmetal |
