| A | B |
|---|
| Dmitri Mendeleev | russian scientist who discovered patterns when studying elements |
| periodic | happening or repeating at regular intervals |
| periodic law | a law that states that the repeating chemical and physical properties of elements change periodically with the atomic numbers of the elements |
| Henry Moseley | British scientist who deermined the number of protons in an element |
| color of the chemical symbol | indicates the physical state of the element at room temperature |
| the background color | indicates the type of element, metal, nonmetal, or metalloid |
| period | a horizontal row of elements |
| family or group | a column of elements that share chemical properties |
| semiconductors | another name for metalloids |
| Alkalai metals | group 1 on the periodic table; most reactive metals on the chart |
| Alkaline-Earth metals | group 2 on the periodic table |
| Transition metals | groups 3-12 on the periodic chart |
| Boron Group | Group 13 |
| Carbon Group | Group 14 |
| Nitrogen Group | Group 15 |
| Oxygen Group | Group 16 |
| Halogens | Group 17; very reactive nonmetals |
| Noble Gasses | Group 18; unreactive nonmetals |
