| A | B |
|---|
| valence electrons | electrons in outermost energy level of an atom; determines how it will react to other substances |
| alkali metals | most active metal; their atoms have 2 valence electrons |
| alkaline-earth metals | element from group 2 of period table; very active metal bit are less reactive than alkali metals |
| halogens | from group 17; very reactive metal; has 7 valence electrons |
| noble gases | from group 18; unreative metal; 8 valence electrons |
| alkaline earth metals | Group 2; very reactive metal; less reactive than alkali metals; 2 valence electrons |
| transition metals | metals in Groups 3-12; less reactive alkaline-earth metals |
| atoms are made up of | protons, electorns, neutrons |
| energy levels | regions around the nucleus |
| lanthanides | Ce, Pr, Nd, Pm, Sm, Eu, Gd,Tb,Dy, Ho,... |
| actinides | Th, Pa, U, Np, Pu,Am, Cm,... |
| row of elements | period |
| column of elements | group or family |
| number in parenthesis | mass number (most stable element) |
| zigzag line | reminds you where the metals, nonmetals,and metalloids are |
| chemical symbol | indicates physical state at room temperature |
| background color | indicates type of element (Carbon or nonmetal) |
| number in parenthesis | mass number (most stable form) |
