That changing a single atom can have such consequences is the wonder of the chemical world.
Chemistry stands at the pivot of science.
On the one hand it deals with biology and provides explanations for the processes of life. On the other hand it mingles with physics and finds explanations for chemical phenomena in the fundamental processes and particles of the universe. Chemistry links the familiar with the fundamental. Each new atom brings something of the personality of its element to the molecule, and this conspiracy of atoms results in a molecule with properties that are richer than those of each atom alone. The test of all knowledge is experiment.