Basic chemistry help for students and teachers


Interactive Chemistry Worksheets for Students


Periodic table

Naming compounds

Basic formula

Simple compounds

Ionic compounds 1

Ionic compounds 2

Chemical suffixes

Old chemical names

Hydrocarbons - Alkanes

Alkanes, alkenes & alkynes

Alkanols to alkanoic acids


Common compounds

Common formula quiz

Acids, bases and salts

Covalent compounds

Printable worksheets


What is the difference between a chemical symbol and a chemical formula? What are the different types of chemical formula?

Chemical symbols and formula

Chemical symbols from the Periodic Table are used for the individual elements. eg. H for hydrogen, O for oxygen and N for nitrogen.

These chemical symbols are used to construct the chemical formula of

  1. molecular elements. eg. oxygen O2,  ozone O3 and sulfur S8
  2. chemical compounds. eg. water H2O, carbon dioxide CO2 and ammonia NH3



Types of chemical formula

There are many different types of chemical formula. The formula may be empirical, molecular, condensed structural or complete structural formula.

The molecular formula tells us the number and the type of atoms in a chemical element. The molecular chemical formula for glucose is C6H12O6, sucrose is C12H22O11 and octane is C8H18

The empirical formula is the simplest whole number ratio of the elements in a compound. For example, the molecular formula of hydrogen peroxide is H2O2 its empirical formula is HO. Likewise the molecular formula for octane is C8H18 and its empirical formula is C4H9.

The structural formula tells us atoms are arranged in a molecule. This formula may complete or condensed. See octane as an example.