| A | B |
|---|
| Alkali Metal | An element in the first group or family with a valence number of 1. |
| Alkaline Earth Metal | An element in the second group or family with a valence number of 2. |
| Group | A vertical column on the periodic table which is sometimes referred to as a family. |
| Period | A horizontal row on the periodic table. |
| Periodic Table | A chart of the elements arranged into rows and columns according to their chemical and physical properties. |
| Halogen | An element in group 17 on the periodic table with an electron valence number of 7. |
| Metal | The dominate element type on the periodic table with properties of high luster, malleability, and being a good conductor of electricity and/or heat. |
| Metalloid | The elements running along the periodic steps that have the characteristics of metals and nonmetals. |
| Nobel Gas | An element in group 18 of the periodic table which are chemically inert (chemically nonreactive). |
| Nonmetal | A classification of elements on the periodic table that has no metallic characteristics. |
| Semiconductor | A substance that conducts electricity at high temperatures but not at low temperatures. |
| Transition Element | An element in groups 3-12 consisting of all metals with irregular valence electron numbers. |
| Rows | A horizontal line of cells in a table. |
| Families | Another word for groups, columns of elements on the periodic table |
| atomic mass | The average mass of all the isotopes of an element found in the elemental box |
| elemental box | a box on the periodic table of elements usually containing the element name, symbol, atomic number and mass |
| amu | Atomic Mass Unit; used to indicate mass on an atomic scale. "Mass" of the atom |
| valence electrons | Electrons on the outermost energy level of an atom, determines its reactivity, determines which family the element resides in. |
| column | A vertical (up and down) stack of cells in a table or worksheet. |
| atomic number | the number of protons in the nucleus of an atom |
