History of the Periodic Table

By Kelsey White

What is it?

The periodic table is a display of the chemical elements organised by their atomic numbers, electron configurations, and their recurring chemical properties. Elements are organised in the order of increasing atomic numbers. It is separated into two groups, metals and non-metals. The metals are made up of metalloid's, alkali metals, alkaline earth metals, transition metals and non-transition metals. Non-metals are made up of halogens, noble gases and other non-metals. They can be categorised into groups and periods. Groups are the horizontal lines, and periods are the vertical.

Who created it?

In 1789 Antonie Lavisoer published a list of 33 elements which he grouped into gases, metals and non-metals. In 1829 Johann Dobereiner observed that many of the elements could be grouped together based on their chemical properties. For example lithium, sodium and potassium are grouped together as they are all soft reactive metals.

How are elements labeled?

Elements are labeled with their atomic symbol, atomic number, mass number and the name of the element. It sometimes also shows the electron configuration or the number of valance electrons it contains in its outer shell.