Groups+and+Periods

=Groups and Periods=

The periodic table is a tabular display of all the elements. They are divided into three types of elements- nonmetals, metalloids, and metals. It organizes the elements primarily by atomic number, but there are also other organizational methods such as groups and periods. Groups, or families, are the columns of the periodic table. They signify the amount of valence electrons __only__ for non-metals and the "island of certainty" (Aluminmum, zinc, silver, and cadmium). Some important groups are the noble gases (group 18), that do not react with any elements, the alkali metals (group 1), which are the most reactive, and the alkali earth metals (group 2). Periods are the horizontal rows in the table and there are seven groups. They show outermost electron shell.

The periodic table above shows all the different elements. The groups run vertically and the periods run horizontally.

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[|Helpful periodic table]