COMPOUNDS AND THEIR PROPORTIONS 

All elements are represented by a chemical symbol. It is either a single capital letter, or a capital letter followed by a small letter.

Examples: Ca = calcium Cu = copper

C = carbon N = nitrogen

Combinations of symbols represent compounds. These compounds are called chemical formulas.

Example: H₂0 2 hydrogen atoms

1 oxygen atom

If no number is shown beside the symbol, a 1 is understood.

If more than 1 atom is present, a small number is shown after the atom to indicate how many atoms are in the compound.

NaHCO₃ = Sodium Hydrogen Carbonate (baking soda) 1 atom Na = Sodium

1 atom H = Hydrogen

1 atom C = Carbon

3 atoms O = Oxygen