Explain various chemical formulas?

Chemical Formulas

A molecule can be represented in any of three ways: its chemical formula, structural formula, or Lewis diagram. A chemical formula is a type of shorthand which designates the composition of molecules. The formula contains the symbols of the constituent atoms and their ratio in the compound. If more than one atom of the same type is present, the number is indicated by a subscript following the symbol. Occasionally, atoms join covalently to form polyatomic ions, or radicals. These groups are surrounded by parentheses in the chemical formula.

Structural formulas and Lewis diagrams give information about the arrangement of atoms in the molecule. The sharing of two electrons by two atoms in a covalent bond, is represented by a line drawn between the atoms in a structural diagram, and by two dots denoting the electrons in a Lewis diagram.

 Although the chemical composition is given in the formulas, many complicated molecules can have various arrangements of the same atoms. A structural formula is required to describe these different structures, called isomers.

The chemical formula for ionic compounds is written with a superscript designating the charge on each atom or polyatomic particle as follows: