<span>The Periodic
table of elements is divided in 18 columns, which is called a group or a
family. A group of elements share the same physical or chemical
characteristics. Elements that are more metallic than others are in group or
column 1 also called Alkali Metals. Alkali metals are considered to be very
reactive and can explode if it comes in contact with water. Hydrogen has been
considered to have the characteristics of both Alkali metal and Halogens. </span>
