Question

What is a chemical formula ? What is the rule for writing a formula correctly ?

Answer 1

A molecular chemical formula employs symbols to denote the molecule of an element or of a compound. The rule for writing chemical formula is as follow:

Firstly, write the symbols with positive charge valency first. Secondly, write the valency of each atom on the top of its symbol. Thirdly, divide the valency number by their highest common factor ignore the positive or negative radicle. Interchange the valency of the radicle. Lastly, write the interchanged valency number to the lower right of the radicle.