The Periodic Table shows us all the known elements in our planet. In the Periodic Table, the elements are presented in increasing atomic number.

Every vertical column represents a Group or Family. Groups are considered the most important method of classifying the elements, because the elements have very similar properties and exhibit a clear trend in properties down the group. Under the International naming system, the groups are numbered numerically 1 through 18 from the left most column (the alkali metals) to the right most column (the noble gases).

The rows, in the periodic table, are called Periods, there are 7 periods, the first one contains only two elements, hydrogen and helium, they are filling orbital 1s. The second and third periods have 8 elements, because involve elements with orbitals s and p and follow the octet rule. Elements in period 4 start with d orbitals (d-block), and makes the periodic table more extensive, including 10 more elements than the previous periods, these elements are the Transition Elements. When elements include orbitals f (f-block) the periodic table needs 14 more spaces, they are covered for Lanthanides and Actinides.


Periodic Table Levels of Energy