Periodic Table

The periodic table of the chemical elements is a systematic arrangement of elements, in the form of a table, depending on their properties.

Link: http://agracadaquimica.com.br/imagens/tabela_periodica2.png Accessed  11/01/2013

For years, many people have created several models for organizing the known elements. In 1869, Mendeleev presented a classification, which is the basis of the modern periodic table, placing the elements in increasing order of their atomic masses, distributed in eight horizontal stripes (periods) and twelve vertical columns (families). Found that the properties varied periodically with increasing atomic mass.

Link: http://www.vestibulandoweb.com.br/quimica/teoria/historia-tabela-periodica-3.jpg Accessed 11/01/2013

In the modern periodic table, elements are arranged in order of increasing atomic number.

Construction of the Periodic Table

The elements are placed in horizontal bands (periods) and vertical bands (groups or families).

In a group, the elements have similar properties and, in a period, the properties are different.

In the table there are seven periods. The groups are numbered 0 through 8. With the exception of groups 0 and 8, each group is divided into two subgroups, A and B. The group is named 8 8B and consists of three vertical strips.

Nowadays, each column is called a group. There is therefore 18 groups numbered 1 through 18.

Family 1A: Alkali Metals. Ex: Li, Na, K, Rb, Cs, Fr
Family 2A: Alkaline Earth Metals
Family 3A (13): Family Boro
Family 4A (14): Family Carbon
Family 5A (15): Nitrogen Family
Family 6A (16): Chalcogens
Family 7A (17): Halogens
Family 8A (18): Noble Gases

Family B (3-12): Transition Metal

Link: http://andromeda.rutgers.edu/~huskey/images/periodic_table_color1_1024x768_w.png Accessed 11/02/2013

The table can be divided into three groups: Metals, Nonmetals and Metalloids.

Features Metals (represented by the pink color in the table above):

• Gloss metallic

• Conduct electrical current and heat

• Malleable

• Used in coins and jewelry

Features Nonmetais(represented by the green color in the table above):

• Do not display brightness

• No power conductors

• Shatter (Solid State)

• Production of gunpowder and tires

Features Metalloids(represented by the brown collor in the table above):

• Gloss metallic

• Small electrical conductivity

• Shatter

Sources: http://www.infoescola.com/quimica/tabela-periodica/

http://pt.wikipedia.org/wiki/Tabela_peri%C3%B3dica