- There are a total of 118 elements discovered till date. These are arrangeed systematically in the periodic table. The modern period table (Long form) has 18 vertical columns called GROUPS and 7 horizontal rows called PERIODS, the details of which will be discussed in s separate chapter. - Each element has a unique one or two letter short identity code called SYMBOL. - Most of them are derived from their Latin names, with a few from Greek, German and English names. Some elements are named after scientists, important places, planets, etc. - If more than one elements have the same starting letter, then a second letter from the name is used to distinguish that element from the rest. The first letter is capital and the second letter (if any) is small. - The following tables give the symbols of elements with their atomic numbers(Z) inside parentheses in a group-wise