| A | B |
|---|
| representative elements | highest occupied s and p sublevels are partially filled |
| transition metal | highest occupied s sublevel and a nearby d sublevel contain electrons |
| Group 2 | metals having only 2 electrons in the highest occupied energy level |
| atomic radius | one half the distance between the nuclei of two atoms of the same element when the atoms are joined |
| ionic radius | decreases for cations and anions from left to right across a period |
| electronegativity | measures the ability of an atom to attract electrons when the atom is in a compound |
| ion | an atom or group of atoms that has a positive or negative charge |
| noble gases | elements in which the highest occupied sand p sublevels are filled |
| halogens | name given to nonmetals of Group 17 |
| inner transition metals | The highest occupied s sublevel and a nearby f sublevel contain electrons |
| ionization energy | energy required to remove an electron from an atom |
| cation | positively charged ion |
| alkali metals | name given to Group l elements |
| metals | good conductors of heat and electric current |
| anion | negatively charged ion |
| nonmetals | poor conductors of heat and electric current |
| metalloids | properties similar to those of metals and nonmetals, depending upon conditions |
| modern periodic law | elements in order of increasing atomic number, show a periodic repetition of physical and chemical properties |
| Mendeleev’s periodic law | elements in order of increasing atomic mass, show a periodic repetition of physical and chemical properties |
| alkaline earth metals | name given to Group 2 elements |
| s block elements | He and the elements in Groups 1 and 2 |
| p block elements | the elements in Groups 13, 14, 15, 16, 17 and 18 excluding He |
| d block elements | the elements in Groups 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 |
| f block elements | f block elements – the elements of the Actinide and Lanthanide Series |
