THE PERIODIC TABLE OF THE ELEMENTS

The following links is an interactive periodic table. Enjoy it!!  
http://www.lenntech.es/periodica/tabla-periodica.htm

I would like to share with the whole group, a teaching tool that the teachers of chemistry we use constantly in class: THE PERIODIC TABLE OF THE ELEMENTS.

The periodic table of the elements classified, organizes, and distributes the various chemical elements, according to their properties and characteristics; its primary function is to establish a specific order by grouping elements. The table is often attributed to Dmitri Mendeleev who ordered the elements based on the manual variation of the chemical properties, while Julius Lothar Meyer, working separately, carried out a management from the physical properties of the atoms. The current form is a modified version of the Mendeleyev; was designed by Alfred Werner.

In the vertical columns of the periodic table they are known as groups. All the items that belong to a group have the same atomic valence, and therefore have similar characteristics or properties among themselves.

The horizontal rows of the periodic table are called periods. Contrary to such as in the case of the groups of the periodic table, the elements that make up the same row have different properties but masses similar: all the elements of a period have the same number of orbitals. Following this rule, each element is positioned according to its electronic configuration.

Today there are many types of regular tables with different designs, some are the following:

• I would be very good to consider the question, why this type of regular tables are not used in our classes?