Periodic Table of Elements

Between the period of 1800 and 1900, there were more than half of the elements known today were already discovered.  And there were elements that are found to have similar physical and chemical properties, and these elements were grouped by some scientist according to a certain basis. The arrangement of elements according to similar physical  and chemical properties is called the Periodic Table of Elements.   

The Modern Periodic Table is already arranged according to increasing atomic number in which elements having similar physical chemical properties were grouped as one group.  Examples of these elements are lithium (Li), sodium (Na), potassium (K) are all soft and very reactive metals.  Helium (He), Neon (Ne), and Argon (Ar) are very nonreactive gases.  The Modern Periodic Table is shown below:

The Modern Periodic Table is divided into several vertical columns called group or families and horizontal rows called the periods.  Group or families are categorized as the A families (Representative elements) and the B families ( Transition elements).  The Group A elements are divided into 8 groups (group IA to group 0, previously known as the group VIIIA).  These groups have special name:  Group IA elements are called Alkali Metals, group IIA elements are Alkaline Earth Metals, group IIIA elements are called Boron Group, group IVA elements are called Carbon group, group VA elements are called Nitrogen group, group VIA elements are called the Chalcogen group,  group VIIA are called Halogen group and the group 0 elements (VIIIA) are called Noble gases.

The elements are also divided into three categories: the metals, nonmetals and metalloids or semi-metals.  Metals are found on the left corner of the periodic table.  They are known to be conductors of heat and electricity, malleable, ductile, luster, and have high melting and boiling point.  Nonmetals are located on the upper right corner of the periodic table.  They are known to be nonconductors of heat and electricity, brittle, low melting and boiling point, no luster.  Metalloids or semi-metals are elements that possess the characteristics of both metal and nonmetal, located in between metals and nonmetals.  You can locate the semi-metal elements on the periodic table presented above those elements with light blue in color.