Final answer:
The correct chemical formula for sulfur trioxide is SO3, containing one sulfur atom and three oxygen atoms, and is different from sulfur dioxide, which is SO2.
Step-by-step explanation:
The correct chemical formula for sulfur trioxide is SO3. This compound contains one sulfur atom and three oxygen atoms, adhering to the prefix 'tri-' indicating three oxygen atoms. In comparison, SO2 is sulfur dioxide, with two oxygen atoms. Chemical nomenclature provides unique names for different compounds to distinguish their unique chemical and physical properties. Sulfur trioxide and sulfur dioxide not only have different formulae but also differ significantly in their properties.
For sulfur dioxide (SO2), using formal charge considerations, the correct arrangement of atoms would be OSO, resulting in the most stable structure with the lowest formal charges. Moreover, the reaction of sulfur dioxide with oxygen producing sulfur trioxide can be expressed by the chemical equation 2SO2(g) + O2(g) > 2SO3 (g), which is an exothermic process with a ∆H° of -197.8 kJ.