| A | B |
|---|
| Dmitri Mendeleev | Russian chemist, discovered a pattern to the elements |
| periodic | describes something that occurs or repeats at regular intervals |
| periodic law | states that the repeating chemical and physical properties of elements change periodically with the atomic numbers of the elements |
| Mendeleev saw the elements were arranged in order by | increasing atomic mass |
| period | in chemistry, a horizontal row of elements in the periodic table |
| group | a verticle column of elements in the periodic table; elements in a group share chemical properties |
| Elements are classified as? | metals, non metals, and metalloids |
| atomic number | found on the periodic square of an element at the top, represents the number of protons in an element |
| atomic mass | found at the bottom of the periodic square for the element, total weight of protons and neutrons |
| chemical symbol | a one or two letter symbol that represents an element |
| Noble Gases` | elements that don't react readily with other elements |
| metalloids | elements having properties of metals and nonmetals |
| Hydrogen | the most abundant element in the universe |
