The molecular structure of water contains two atoms of hydrogen and one atom of oxygen. when water reaches its boiling point and turns into water vapor, what happens to its molecular structure?

The water reaches its boiling point and turns into water vapor. This process is a physical change. The change is substance status. And the physical change will not destroy the molecular structure. So the molecular structure will not change.

Evaporation: this is when warmth from the sun causes water from oceans, lakes, streams, ice and soils to rise into the air and turn into water vapour (gas). water vapour droplets join together to make clouds! condensation: this is when water vapour in the air cools down and turns back into liquid water.