Symbol may be defined as the abbreviation used for the name of an element. The symbol of an element are generally either the first letter or the first two letters of the name of element or the first and the third letters of the name of the element.

For example, the symbol of some elements are the first letter of the name of that element such as Hydrogen- H, Oxygen- O.

Some symbols are derived from the first two letters of the names of the element such as Calcium- Ca, Aluminum- Al.

Some symbol derived from the first and the third letter of the names of the elements such as Arsenic-As

Symbol of many elements are taken from their English name, while symbol of many elements are taken from their Greek or Latin names such as the latin name of sodium is Natrium, hence the symbol is Na.