On the basis of the theories of Rutherford , he published his theory of electrons . He introduces the theory of electrons traveling in orbits around the nucleus of the atom in 1913 and the chemical properties of the orbit . On the basis of Rutherford 's theories , Bohr published his model of atomic structure in 1913 , introducing the theory of electrons traveling in orbits around the atom 's nucleus , the chemical properties of the element being largely determined by the number of electrons in the outer orbits .