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INTRODUCTION
A periodic table is an arrangement of elements according similarities in their properties. there are about 92 naturally occurring elements and another nearly 26 additional elements that have been artificially created by scientist using scientific technology. This makes a total of about 118 elements now readily found in nature.
These elements are recognized and are all represented on the Periodic Table of Elements.Each element is represented by a one or two letter code, where the first letter is always capitalized and, if a second letter is present, it is written in lowercase. For example, the symbol for Hydrogen is H, and the symbol for carbon is C. Some of the elements have seemingly strange letter codes, such as sodium which is Na. These letter codes are derived from latin terminology. For example, the symbol for sodium (Na) is derived from the Latin word, natrium, which means sodium carbonate.
Elements in the periodic table can be broken up into different general classes based upon similarities in their properties. Going from left to right across the periodic table, the elements can be broken up into metals, metalloids, and nonmetals.
All of the known chemical elements are arranged in the format of a table. The table has been set up in such a way that the characteristics of each different element can be predicted by their position on the table.
On this periodic table, you can see that the elements on the left-hand side of the table are the metals, while the elements on the right are the non-metals (Hydrogen is the only exception to this rule and will be explained in the subsequent sections). The metalloids (also termed semi-metals) occur in a stairstep pattern between the metals and nonmetals . The table also shows the positions of the metals, nonmetals and metalloids on the periodic table
History of the periodic table
The history of periodic table dates back into 1680 when Robert Boyles along with other scientist discovered phosphorous. In 1807,atleast another 47 elements had been discovered and scientists began to see patterns in their characteristics. In 1863,John Newlands, an English Chemist divided the then discovered 56 elements into 11 groups, based on characteristics.
Later in 1871, Dmitri Mendeleev, a Russian chemist, organized all the known elements according to their atomic mass and other similar properties. From these elements and their properties, started the development of the periodic table, arranging chemical elements by atomic mass. He predicted the discovery of other elements, and left gaps in his periodic table for them.He also made some bold predictions regarding the properties of those undiscovered elements.
Later, when elements were discovered whose properties closely matched Mendeleev’s predictions, his version of the table gained favor in the scientific community. Because certain properties of the elements repeat on a regular basis throughout the table (that is, they are periodic), it became known as the periodic table.
In 1911 Rutherford and German physicist Hans Geiger discovered that electrons orbit or move round the nucleus of an atom. Three years later, he identified protons in the atomic nucleus. In 1932 James Chadwick discovered neutrons, and isotopes. This was the complete basis for the periodic table