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 molecule is no longer attracted as much to the other molecules due to the hydrogen bonds. As you boil the water (add energy) the kinetic energy of the water molecule increases which eventually becomes stronger than the multiple hydrogen bonds that was keeping the water molecules together. So essentially the water molecule "escapes" and and is able to go to the gas state. I hope that answers your question