The periodic table is one of the most important tools in the history of chemistry. It describes the atomic properties of every known chemical element in a concise format, including the atomic number, atomic mass and relationships between the elements. Elements with similar chemical properties are arranged in columns in the periodic table.
The periodic table of the elements describes the atomic structure of all elements that are known to mankind. For instance, by looking at the periodic table, a person can find out how many electrons the element has and how much it weighs. Each element has its own separate set of such data; no two elements are the same. Thus, if someone is uncertain what matter he has, he can look at the atomic structure of the material, compare it to the information in the periodic table, and identify the material by matching it to the element on the table with the same data.
Families and Periods of the Elements
The elements in the periodic table are grouped in particular families and periods (vertical and horizontal rows). The elements in each family or period have similar or dissimilar characteristics. The table thus is a quick reference as to what elements may behave the same chemically or which may have similar weights or atomic structures.
The information contained in the periodic table (such as atomic weight and what elements are similar) lets scientists know how the elements are put together atomically and how they will behave. Once scientists understand this data, they can apply it in experiments. These experiments can be something as simple as combining hydrogen and oxygen to make water, or they can be as dramatic as making a hydrogen bomb.
Classification of the Elements
The periodic table can be used to identify the matter already discovered by mankind. However, if new matter is discovered, then the atomic structure of the new matter can be compared to the elements in the table in order to classify the new material. Scientists can use the data in the table to figure out how the new matter may behave or what elements to which the new matter may be similar through this comparison.
Scientists can use the information in the periodic table to know when elements have been acted upon in some way. For instance, if scientists know that the basic form of an element has a particular number of neutrons, then they know that something has to have happened to the element if an isotope (an atom with the same number of protons but a different number of neutrons than the base element) is discovered. They may not know exactly what caused the isotope to form, but they can know with certainty that something did occur. This gives historical perspective.