| A | B |
|---|
| Periodic Law | The physical and chemical properties of the elements are periodic functions of their atomic numbers |
| Periodic Table | an arrangement of the elemtns in order of their atomic numbers so that elements with similar properties fall in the same column, or group |
| Lanthanides | the 14 elements with atomic numbers from 58 to 71 |
| Actinides | the 14 elements with the atomic numbers from 90 to 103 |
| Alkali metals | the elements in Group 1 of the periodic table (lithium, sodium, potassium, rubidium, cesium, and francium) |
| Alkaline earth metals | the elements in Group 2 of the periodic table (beryllium, magnesium, calcium, strontium, barium, and radium) |
| Transition elements | the d-block elements are metals with typical metallic properties |
| Main-group elements | the p-block elements, together with the s-block elements |
| Halogens | the elements in Group 17 (flourine, chlorine, bromine, iodine, and astatine) |
| Atomic radius | one-half the distance between the nuclei of identical atoms that are bonded together |
| Ion | an atom or group of bonded atoms that has a positive or negative charge |
| Ionization | Any process that results in the formation of an ion |
| Ionization energy | the energy required to remove one electron from a neutral atoms of an element |
| Electron affinity | the energy change that occurs when an electron is acquired by a neutral atom |
| Cation | a positive ion |
| Anion | a negative ion |
| Valence electrons | the electrons available to be lost, gained, or shared in the formation of chemical compounds |
| Electronegativity | a measure of the ability of an atomin a chemical compound to attract lectrons |
