Sulfur dioxide reacts with oxygen to form?

The Reaction of Oxygen with Sulfur Dioxide to make Sulfur Trioxide.

Sulfur dioxide is made by reacting sulfur with oxygen.

Sulfur dioxide can be made to react with more oxygen
to make sulfur trioxide.
This is another example of oxidation.

The reaction is reversible (shown by the  arrow).
The forward reaction (from left to right) is exothermic.

This is the balanced chemical equation for the reaction of
sulfur dioxide with oxygen.

sulfur dioxide  +  oxygen    sulfur trioxide.
2SO2(g)        +    O2(g)             2SO3(g)

The industrial conditions for the chemical reaction are
1) The Temperature is 450 °C.
2) The Pressure is between 1 and 2 atmospheres.
3) A Vanadium(V) oxide (V2O5) catalyst is used.

"the periodic table is arranged in order of atomic number."