Chemical Nomenclature

In clinical settings, "Sodium Chloride" and "Sodium Chlorite" are two very different substances. Precise naming is vital for patient safety.

1. Transition Metals (The Roman Numeral Rule)

Because metals like Iron (Fe) or Copper (Cu) can have different charges, we specify the charge in the name:

  • FeCl2: Iron (II) chloride (Uses Fe2+)
  • FeCl3: Iron (III) chloride (Uses Fe3+)

2. Molecular Compounds (Greek Prefixes)

For nonmetal compounds, use prefixes to show the number of atoms:

Formula Prefixes Used Name
SO2 di = 2 Sulfur dioxide
N2O5 di = 2, penta = 5 Dinitrogen pentoxide

di = 2
tri = 3
tetra = 4
penta = 5
hexa = 6

3. Clinical Acids to Memorize

These acids are frequently encountered in respiratory therapy and metabolic studies:

  • HCl (aq): Hydrochloric acid (Stomach acid)
  • H2CO3: Carbonic acid (Formed by CO2 in the blood)
  • HNO3: Nitric acid
  • H2SO4: Sulfuric acid

Hydrates

Some salts can be hydrated, meaning that they have one or more water molecules as part of their crystal structure.

For example, CuSO4∙5H2O is the salt copper (II) sulfate with 5 water molecules attached in the crystal.

The Greek prefix for the number 5 is ‘penta’, so this would be a pentahydrate … copper (II) sulfate pentahydrate.