| A | B |
|---|
| Ionization energy | the energy required to REMOVE one electron from an atom of an element; measured in kJ/mol |
| Electronegativity | a measure of the relative tendency of an atom of an element to attract or gain electrons; the “desire” to gain electrons; electronegativity is based on a scale from 0.0 – 4.0 |
| Atomic Radius | the radius of an atom; measured in pm (picometers) |
| Ionic Radius | the radius of an ion; cations (lose electrons) decrease in radius; anions (gain electrons) increase in radius |
| Chemical Reactivity | the tendency for an atom of a given element to gain or lose electrons when interacting with an atom of another element |
| METAL | atoms tend to transfer electrons to nonmetals when they react |
| NONMETAL | atoms tend to gain or share electrons when they react |
| In the same PERIOD | it is the number of electrons that chiefly determines reactivity. The smaller the number of electrons transferred between reacting atoms, the more vigorous the reaction. |
| In the same group | elements have the same number of valence electrons and it is the atomic radius which largely determines reactivity. The larger metals lose outer shell electrons more easily and smaller nonmetals (whose attraction for electrons by the nucleus is greater) are more likely to take electrons away from other metals (or share with other nonmetals). |
| Metallic Character | metals are malleable (can be hammered into thin sheets and bent), ductile (can be drawn into wire), have luster (shine), and conduct electricity; metals tend to lose electrons; all metals have a “sea of mobile valence electrons” |
| Nonmetallic character | nonmetals are NOT malleable, ductile, do NOT have luster, and do NOT conduct electricity |
| Metalloids | have properties of both metals and nonmetals; located along the “staircase,” except for aluminum (Al) |
| Alkali metals | all elements located in Group 1 on the periodic table except hydrogen; contains the most reactive metals |
| Alkaline Earth metals | all elements located in Group 2 on the periodic table |
| Halogens | all elements located in Group 17 on the periodic table; most of the halogens have high electronegativities |
| Noble Gases | all elements located in Group 18 on the periodic table; inert (do not tend to react with atoms of other elements); have a full valence shell |
| Transition metals | the three rows of elements in the middle of the periodic table from scandium (Sc) to mercury (Hg); reactivity is based on the elements with which they are combined |
| Periodic | cyclic; repeating pattern/cycle |
| Periodic Law | elements of the periodic table are periodic functions of their atomic number |
