Alfred Werner was awarded to Nobel prize in Chemistry in 1913. He was born in Mulhouse, Alsace in1866. He entered in chemistry at the age of 18, and established the spatial relationship of atoms in molecules at the age of 24. He contributed a milestone in the theory of molecules. In 1891, he worked with Marcellin Berthelot in the College de France, in Paris. Then in 1893, he stated the theory of variable valence and defined the coordination number describing the number of atoms that can be arranged around a central nucleus. He established structural properties within the molecules that was determining to build the first models of the chemical bond. We shall see the different steps in the evolution of the theory of the chemical bondings during the 20th century. A brief survey of the state of the art in theoretical chemistry follows.