Periodic table

The question to ask is: with so many elements and the different electron configurations in an atom, is there a simple way to classify it all? Certainly, it is called the Periodic Table.

The periodic chart is simple and clear. Each element is defined by its atomic number (number of protons in the nucleus / number of electrons) and it increases by each row (period) and down each column (group). For now, just know that the periods are ordered according to successive filling of shells with electrons, while the groups reflect the number of electrons in the outer (valency) shell. These outer shells are important for they decide the chemical properties of the atom.

In sum, the table is useful to know how the chemical elements are organized on the basis of atomic numbers, electron configurations, and chemical properties. Using the table you can predict properties of various elements, know the relations between them, and analyze their chemical behavior.