| 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) |
| Chemical Reactivity | the tendency for an atom of a given element to gain or lose electrons when interacting with an atom of another element |
| c.) In the same PERIOD | it is the number of electrons that chiefly determines reactivity. The smaller the number of electrons transferred between reacting atoms |
| d.) 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 loose 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) |
| Nonmetallic character | nonmetals are NOT malleable |
| Metalloids | have properties of both metals and nonmetals; located along the “staircase |
| 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 |
| Periods | horizontal rows on periodic table |
| Groups | vertical columns on periodic table |
| Octet | full valence shell; 8 electrons |
| States of matter | any of the three phases in which an element can exist; solid (s) |
| Solids | have definite shape and definite volume; most elements are solids at STP |
| Liquids | take the shape of their container and have definite volume; only 2 elements exist as liquids at STP: Br |
| Gases | have no definite shape and fill their container; at STP this includes H |
| Diatomic elements | elements that can’t exist alone in nature; travel in pairs; contain 2 identical atoms (same element); “Siamese twins |
| Allotrope | 1 of 2 or more different forms of an element (nonmetal) in the same phase |
| Isoelectronic | atoms or ions that have the SAME number of ELECTRONS |
| Ex: F- | Ne |
| Families | elements with similar properties; group 1 |
