Periodic Table

http://www.bpc.edu/mathscience/chemistry/history_of_the_periodic_table.html

The periodic table is divided in three section due to the properties ofthe atoms in those groupsMetals – BlueNonmetals – YellowMetalloids – Red

Metals: left side of stairstep line in the Periodic Table shown above (including lanthanides and actinides) except H. The majority of the elements are metals. Metals have the following properties:

a) conduct heat and electricity

b) malleable (can be hammered into sheets and shaped -- like coins and jewelry)

c) ductile (can be drawn into wire)

d) often shiny

e) tend to lose electrons (become positively charged) in chemical reactions

Nonmetals: right side of stair-case line in the Periodic Table shown above plus hydrogen (H). This category does not include last column of inert elements or noble gases.

Semi-metals or Metalloids: The staircase-shaped line between metals and non-metals has several elements on or near it that have properties somewhere between the two categories or exhibit some of the qualities of both. For this reason they are called semi-metals or metalloids (meaning metal-like).This category includes silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), and tellurium (Te).Some chemists also include boron (B), aluminum (Al), polonium (Po), and astatine (At) in the semi-metals.

Noble gases or inert elements: --He, Ne, Ar, Kr, Xe and Rn, which are not considered metals or nonmetals.

Hydrogen: Elements in the same group tend to have similar chemical properties, but H is a nonmetal, so why is it grouped

with the alkali metals? Although H is considered a nonmetal, it often behaves

chemically like the alkali metals because of its unique electron configuration. Because of its unique electron configuration, H

can frequently be found with a +1 charge like the alkali metals and therefore it often undergoes chemical reactions that alkali

metals undergo. On the other hand, because of its unusual electron

configuration, H can often be found with a -1 charge (like the halogens).

In its pure form, hydrogen is also a diatomic molecule (H2) like the other halogens.

The halogens are nonmetals, so when H acts like the other halogens, it is behaving more like a nonmetal.

Because of this ambivalent behavior of H, some people place H in two places on the Periodic Table: in Group IA and also in Group VIIA. Other Periodic Tables place H at the top of the Periodic Table -- leaving it out of all Groups. Most Periodic

Tables, however, show H in Group IA.

Ionic charge, or oxidation number is the same for all atoms in a group because these atomseither lose electrons (becoming cations) or gain electrons (becoming anions)to have a octet configuration like a noble gas.

http://www.chemprofessor.com/ptable.htm

Valence electron number is the same for all atoms of the same group and represents the total electrons in the outer electron shell

The valence electrons of atoms take on specific orbital shapes that are associated with specific parts of the chart – this is helpful whenwriting electron configuration notation

Periods – or rows represent the different energy levels – there are 7 energy levels.

Groups or families

The elements in vertical columns of the periodic table have similar chemical properties. The sets of elements are called groups or families.

Alkali metals—the metallic elements in group 1 are called the alkali metals because they react with water to form alkaline solutions. Note that hydrogen, though it is in group 1, is not an alkali metal.

Alkaline earth metals—the elements in group 2 have properties similar to those of group 1 but are slightly less reactive, hence “earthy.”

Halogens—the elements in group 17 are known as the halogens (‘salt former’ in Greek) because they easily form negative ions (which are found in the class of compounds called salts). They also form diatomic molecules along with Nitrogen, Oxygen, and Hydrogen.

Noble or inert gases—the elements in group 18 are known as noble gases because they do not readily form compounds. The word noble, in this context, is the opposite of the word base, or easily corruptible.

Reading the Periodic Table: Carbon

To describe the information contained within each individual box we will use a specific example: carbon.

Click here for detailed information of the information: SparkNotes: The Periodic Table: Reading the PeriodicTable

                  WebElements

Periodic Table of Elements

Periodic Table on Line: