| A | B |
|---|
| symbol | a shorthand notation for the elements on the PT |
| atomic number | the number of protons in an atom |
| atomic mass | the weighted average of the masses of all the naturally occurring isotopes of an element |
| periodic table | an organized table of all the known elements |
| families (or groups) | columns (vertical) on the periodic table |
| periods | rows (horizontal) on the periodic table |
| chemical formula | a shorthand notation for a compound or diatomic element using chemical symbols and numbers |
| similar properties | elements in the SAME GROUP will have similar properties |
| ionic bond | the force of attraction between oppositely charged ions |
| covalent bond | the force of attraction between the nuclei of atoms & the electrons shared by the atoms |
| negative ion | a particle that gains electrons |
| metals | found to the left of the zigzag line on PT; solid; good conductors; malleable; ductile; shiny |
| nonmetals | found to the right of the zigzag line on PT; not malleable; not ductile; not shiny; poor conductors |
| metalloids | found along zigzag line on PT; properties of both metals & nonmetals |
| element | a pure substance that cannot be broken down into simpler substances |
| chemical bond | a force of attraction that holds two atoms together |
| chemically stable | the element has a complete outer shell - it will not react with others |
| ion | charged particles |
| Alkali Metals | group 1; very reactive metals |
| Alkaline-earth Metals | group 2; reactive metals |
| Transition Metals | groups 3-12 |
| Halogens | group 17; very reactive nonmetals |
| Noble Gases | group 18; unreactive nonmetals - outer shell is full |
| valence electrons | the electrons in the outermost energy level of an atom |
| positive ion | a particle that loses electrons |
| metallic bond | the force of attraction between a positively charged metal ion & the electrons in a metal |
