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Reading the Periodic Table:
Objectives:
1. Explain why elements in a group have similar properties.
2. Identify the four blocks of the periodic table.
Key Terms:
group family period alkali metal alkaline earth metal halogen noble gas metal nonmetal semimetal valence electron abbreviated electron configuration noble gas inner core
Web Resources:
Notes: (5-2)
The Periodic Table:
Our current periodic table lists 109 elements. It is arranged according to the periodic law:
 | Elements are arranged in order of increasing atomic number, their physical and chemical properties show a periodic pattern. |
| Elements that have similar properties are arranged in groups or families - vertical columns |
| The horizontal rows are called periods. |
(helios.augustana.edu/physics/ 301/periodic-table-fix.jpg)
| Each period contains more elements than the previous one. This has to do with the increasing energy levels (n=1, ...) of the atom. |
| period 1 - 2 elements |
| period 2 & 3 - 8 elements |
| period 4 & 5 - 18 elements |
| period 6 - 32 elements |
Labeling and Naming:
There are currently 3 numbering schemes used in chemistry for the ordering of groups.
| Roman - IA - VIIIA & IB-VIIIB |
| Arabic - 1A-2A, 3B-8B, 1B-2B, 3A-8A |
| Number - 1-18 |
Families:
| 1A - alkali metals |
| 2A - alkaline earth metals |
| 7A - halogens |
| 8A - noble gases |
| 4A - sometimes known as the Carbon group |
Exception - Hydrogen can be better placed in group 7A. Although, some books place it in both.
(web.buddyproject.org/.../web017/ images/periodic%20table.JPG)
Metals & Non-metals:
Metals include the areas shaded light blue and include the families 1A & 2A. They share many characteristics.
| luster (shine) |
| good conductors of heat and electricity |
| typically solid at room temperature |
| most are malleable and ductile |
Non-metals are shaded light red in most periodic tables and form a diagonal from C-6 to Rn-86 and include all the elements of that corner including H. They share some of these characteristics.
| do not possess luster |
| poor conductors of heat and electricity |
| neither malleable or ductile |
| many are gasses at room temperature |
| can be solid, semisolid, gas, or liquid (Br). One is the hardest material on Earth |
Semimetals or metalloids are shaded light light purple in most periodic tables form a diagonal from B-5 to At-85 and include all the elements Ge-32 and Sb-51. They share some of these characteristics.
| have some properties of metals and some of non-metals |
Electron Configuration:
As you learned earlier, the number of protons in an atom is equal to the number of electrons in the atom if it is neutral. The periodic table allows you to predict the bonding of an atom by allowing you to see the number of electrons in the valence orbital. The valence orbital is the highest, outermost orbital of the atom and is the only one involved in the bonding of the atom. Here are some hints for predicting valence electrons:
| Elements of the same group (column) have the same valence electrons or configuration |
| s-block is group 1A & 2A |
| p-block is group 3A to 8A |
| These are the representative elements or main group elements |
| d-block is group 3B to 2B (look at the periodic table above because the numbers are not sequential) |
| These are the transition metals |
| f-block is located below the main table |
| These are the inner transition metals or rare earth elements |
To save space on electron configuration notation you can use the abbreviated notation by listing the inner gas core and then the valence electrons.
| H 1S1 |
| Li [He]2s1 |
| Na [Ne]3s1 |
| K [Ar]4s1 |
| Rb [Kr]5s1 |
| Cs [Xe]6s1 |