3.3: Formulas for Common Compounds

2H2O 

Using the compound above, you can name each of the parts of the compound as follows:

Coefficient - The number in front of the molecule that indicates the amount of that element. In this case it is 2 hydrogens and 2 oxygen. 

Subscript Number - The number of atoms of this element. In H2O, there are 2 hydrogen atoms and 1 oxygen atom

Subscript letters - Indicate the state of the molecule. 

l - liquid state

aq - aqueous or solvent is water

s - solid

g - gas

When naming compounds, there is a specific naming convention. Listing from left to right:

1. Metals

2. Non-metals

   • 'ide' is added to the non-metal

   • If there is more than one atom...

     • • 1 atom - mono- Mono is not used on the first element

       • 2 atoms - di-

       • 3 atoms - tri-

       • 4 atoms - tetra

       • etc.

3. If both are non-metals, the name goes left to right of the periodic table.

Polyatomic compounds - These are compounds with more than one compound. 

3. • 'ate' -  more than one compound with a high oxidation state

     • • Na2SO2 - Sodium Sulfate

   • 'ite' - more than one compound with a low oxidation state

     • • Na2SO3 - Sodium Sulfite

Naming Acids

3. • Hydro acids start with 'hydro-' and end in 'ic'

   • Oxoacids (containing oxygen) use '-ous' or the 'ic' suffix. 'Ic' is used when there is more than 1 atom of oxygen. 

     • • H2SO2 - Sulfuric  acid

       • HNO2 - Nitrous  acid

       • HNO3 - Nitric  acid

Read through Page 51, table 3.1 to see other common chemical names and their formula. 

Fill in the following chart using a periodic table, table 3.1 from page 51, and other chemistry resources.