| A | B |
|---|
| average atomic mass | average mass of the mixture of an element's isotopes |
| periodic table | arrangement of elements in repeating changes of properties |
| group | vertical columns of the periodic table |
| dot diagram | uses the symbol of the element and dots to represent electrons in the outer energy level |
| periods | horizontal rows of the periodic table |
| metals | to the left of the stairstep; exist as solids at room temperature; good conductors |
| nonmetals | to the right of the stairstep; most are gases or brittle solids; not good conductors |
| metalloids | along the stairstep; have properties of metals and nonmetals |
