Periodic table is a table in chemistry that is very hard for the students to understand. It consists of 18 columns and 7 rows. The elements in the periodic table are arranged in increasing order of their atomic number. As the hydrogen has atomic number of 1, it is the first element that is placed in the periodic table.
Early Periodic Table:
Periodic table was first discovered by Dmitri Mendeleev in 1869. At that time only 65 elements were arranged on basis of their atomic weight. The first periodic table realized that there are many elements that are unknown. So, the search began to search for the unknown elements that do exist.
The correct explanation of the period table was first given by Henry Moseley in 1913. According to him, elements differ on the basis of proton numbers. He then gave an idea of location of periodic tables and that it can be predicted better by their atomic numbers instead of atomic weight. So, the modern periodic table consists of 108 elements and are arranged in 18 groups. Groups are formed on the basis of elements that have same characteristics and properties. The proton number increases from left to right.
Periods in Periodic Table:
A fact about modern periodic table is that the periods aren’t of the same length. Their length varies. For example, talking about the first group of the periodic table, it contains only 2 elements and is the shortest one. Period 3 and 4 have 8 elements in them and period 5 and 6 consists of 18 elements. The groups are also designed intelligently on basis of their characteristics. For example, the 1st group elements are known as alkali metals and 2nd group elements are known as Alkaline metals. In short, the periodic table is in its finest form today.
Lot more has to come:
Scientists are busy in searching more elements. As they will search more and more elements, there will be changes in the periodic table as well. These elements, if discovered, will also give birth to many new theories and so.